1.Flow of Fluids

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

FLOW OF FLUIDS Review Questions 1.

A fluid is one which (a) cannot remain at rest under the action of shear force (b) continuously expands till it fills any container (c) is incompressible (d) permanently resists distortion

2.

In an incompressible fluid density (a) is greatly affected by moderate changes in pressure (b) is greatly affected only by moderate changes in temperature (c) remains unaffected with moderate change in temperature and pressure (d) is sensible to changes in both temperature and pressure

3.

Potential flow is the flow of (a) compressible fluids with shear (b) compressible fluids with no shear (c) incompressible fluids with shear (d) incompressible fluids with no shear

4.

Potential flow is characterized by (a) irrotational and frictionless flow (b) irrotational and frictional flow (c) one in which dissipation of mechanical energy into heat occurs (d) the formation of eddies within the stream

5.

Newton’s law of viscosity relates (a) shear stress and velocity (b) velocity gradient and pressure intensity (c) shear stress and rate of angular deformation in a fluid (d) pressure gradient and rate of angular deformation

6.

Dimension of viscosity is (a) ML-1T-1 (c) MLT-1T

(b) MLT-1 (d) MLT

7.

Poise is converted into stoke by (a) multiplying with density (gm/c.c.) (b) dividing with density (gm/c.c.) (c) multiplying with specific gravity (d) dividing with specific gravity

8.

Dimension of kinematic viscosity is (a) ML-2 (b) L2T-1 2 (c) L T (d) L2T2

9.

With increase in the temperature viscosity of a liquid (a) increase (b) decreases (c) remains constant (d) first decreases and then increases

10. For water, when the pressure increases the viscosity (a) also increases (b) decreases (c) remains constant (d) first decreases and then increases

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

11. The pressure intensity is the same in all direction at a point in a fluid (a) only when the fluid is frictionless (b) only when the fluid is at rest having zero velocity (c) when there is no motion of one fluid layer relative to an adjacent layer (d) regardless of the motion of one fluid layer relative to an adjacent layer 12. Choose the set of pressure intensities that are equivalent (a) 4.33 psi, 10 ft. of water, 8.83 inches of Hg. (b) 4.33 psi, 10 ft. of water, 20.7 inches of Hg. (c) 10 psi, 19.7 ft. of water, 23.3 inches of Hg. (d) 10 psi, 19.7 ft of water, 5.3 inches of Hg. 13. For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the (a) square of the radial distance (b) radial distance linearly (c) averse of the radial distance (d) elevation along vertical direction 14. The center of pressure is (a) always below the centroid of the area (b) always above the centroid of the area (c) a point on the line of action of the resultant force (d) at the centroid of the submerge area 15. A rectangular surface 3’x4’, has the lower 3 edge horizontal and 6’ below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force in one side of the surface is :(y = specific weight of water) (a) 39.6y (b) 48y (c) 49.2y (d) 58y 16. Fill up the blanks A stream tube is that which has ……… cross-section entirely bounded by stream lines. (a) a circular (b) any convenient (c) a small (d) a large 17. Mass velocity is the independent of temperature and pressure when the flow is (a) unsteady through uncharged cross-section (b) steady through changing cross-section (c) steady and the cross-section is unchanged (d) unsteady ant the cross-section is changed 18. In turbulent flow (a) the fluid particles move in an orderly manner (b) momentum transfer is on molecular scale only (c) shear stress is caused more effectively by cohesion than momentum transfer (d) shear stresses are generally larger than in a similar laminar flow 19. Turbulant flow generally occurs for cases involving (a) highly viscous fluid (b) very narrow passages (c) very slow motion (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

20. An ideal fluid is (a) frictionless and incompressible

(b) one which obeys Newton’s law of viscosity (c) highly viscous (d) none of the above

21. Steady flow occurs when (a) conditions change steadily with time (b) conditions are the same at the adjacent points at any instant (c) conditions do not change with time at any point (d) rate of change of velocity is constant 22. Which of the following must be followed by the flow of fluid (real or ideal)? (i) Newton’s law of viscosity (ii) Newton’s second law of motion (iii) the continuity equation (iv) velocity of boundary must be zero relative to boundary (v) fluid cannot penetrate a boundary (a) I, II, III (c) I, II, V

(b) II, III, V (d) II, III, V

23. Discharge (ft3/sec) from a 24 inch pipe of water at 10 ft/sec will be (a) 7.65 (b) 32.36 (c) 48.22 (d) 125.6 24. The unit velocity head is (a) ft-lb/sec (c) ft-lbf/lb.m

(b) ft-lb/ft3 (d) ft-lb.f/sec

25. Bernoulli’s equation describes (a) mechanical energy balance in potential flow (b) kinetic energy balance in laminar flow (c) mechanical energy balance in turbulent flow (d) mechanical energy balance in boundary layer 26. The kinetic energy correction factor for velocity distribution of laminar flow is (a) 0.5 (b) 1.66 (c) 1 (d) 2 27. The momentum correction factor for the velocity distribution of laminar flow is (a) 1.3 (b) 1.66 (c) 2.5 (d) none of these 28.

The loss due to sudden expansion is (a) V12 – V22 (b) (V1 – V2)3 2gc

(c) V1 – V2

2gC (d) none of these

2gc 29. The loss due to sudden contraction is proportional to (a) velocity (b) velocity head (c) turbulence (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

30. The value of critical Reynolds number for pipe flow is (a) 1300 (b) 10,000 (c) 100,000 (d) none of these 31. Reynolds number flow of water at room temperature through 2 cm diameter pipe at average velocity of 5 cm/sec is around (a) 2000 (b) 10 (c) 100 (d) 1000

32. Shear stress in a fluid flowing in a round pipe (a) varies parabolically across the cross-section (b) remains constant over the cross-section (c) is zero at the center and varies linearly with the radius (d) is zero at the wall and increase linearly to the center 33. Discharge in laminar flow through a pipe varies (a) as the square of the radius (b) inversely as the pressure drop (c) inversely as the velocity (d) as the square of the diameter 34. Boundary layer separation is caused by (a) reduction of pressure below vapor pressure (b) reduction of pressure gradient to zero (c) an adverse pressure gradient (d) reduction of boundary layer thickness to zero 35. The friction factor for turbulent flow in a hydraulically smooth pipe (a) depends only on Reynolds number (b) does not depend on Reynolds number (c) depends on the roughness (d) none of these 36. For a given Reynolds number, in hydraulically smooth pipe, further smoothing (a) brings about no further reduction of friction factor (b) increases the friction factor (c) decreases the friction factor (d) none of these 37. Hydraulic radius is the ratio of (a) wetted perimeter to flow area (b) flow area to wetted perimeter (c) flow area to square of wetted perimeter (d) square root of flow area to wetted perimeter 38. Hydraulic radius of 6” x 12” c/s is (a) 2” (c) 1.5”

(b) 0.5” (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

39. Reynolds number is the ratio of (a) viscous forces to gravity forces (b) inertial forces to viscous forces (c) viscous forces to inertial forces (d) inertial forces to gravity forces 40. Mach. number is the ratio of the speed of the (a) fluid of that of the light (b) light to that of the fluid (c) fluid to that of thesound (d) sound to that of the fluid 41. Power loss in an orifice meter is (a) less than that in a venturi meter (b) same as that in a venturi meter (c) more than that in a venturi meter (d) data insufficient, cannot be predicted 42. The velocity profile for turbulent flow through a closed conduit is (a) logarithmic (b) parabolic (c) hyperbolic (d) linear 43. For laminar flow through a closed conduit (a) Vmax = 2 Vav (b) Vmax = Vav (c) Vmax = 1.5 Vav (d) Vav = 2 Vmax 44. f = 16/NRe is valid for (a) turbulent flow (b) laminar flow through an open channel (c) steady flow (d) none of these 45. Isotropic turbulence occurs (a) where there is no velocity gradient (b) at higher temperatures (c) only in newtonion fluid (d) none of these 46. Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement. (a) f1 = f2 (b) f1 < f2 (c) f1 > f2 (d) data not sufficient to relate f1 and f2

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

47. Bernoulli’s equation for steady frictionless, continuous flow states that (a) total pressure at all sections is same (b) total energy at all section is same (c) velocity head at all section is same (d) none of these 48. Drag is defined as the force exerted by the (a) fluid on the solid in a direction opposite to flow (b) the fluid on the solid in the direction of flow (c) the solid on the fluid (d) none of these 49. Drag co-efficient for flow past immersed body is the ratio of (a) shear stress to the product of velocity head density (b) shear force to the product of velocity head and density (c) average drag per unit projected area to the product of velocity head and density (d) none of these 50. Stoke’s law is valid when the particle Reynolds number is (a) < 1 (b) > 1 (c) < 5 (d) none of these 51. Drag co-efficient CD (a) CD = 16 Re.p (c) CD = 18.4 Re.p

is given by (in Stoke’s law range) (b) CD = 24 Re.p (d) CD = 0.079 Re.p

52. At low Reynolds number (a) viscous forces are unimportant (b) viscous forces control (c) viscous forces control and inertial forces are unimportant (d) gravity forces control 53. At high Reynolds number (a) inertial forces control and viscous forces are unimportant (b) viscous forces predominate (c) inertial forces are unimportant and viscous forces control (d) none of these 54. For flow of fluid through packed bed, the superficial velocity is (a) less than the average velocity through channels (b) more than the average velocity through channels (c) dependent on the pressure drop across the bed (d) same as the average velocity through channels 55. Pressure drop in a packed bed for laminar flow is given by (a) Kozeny-Carman equation (b) Blake-Plummer equation (c) Leva’s equation (d) none of these 56. Pressure drop in a packed bed for turbulent flow is given by (a) Kozeny-Carman equation (b) Blake-Plummer equation (c) Leva’s equation (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

57. Force acting on a particle settling in fluid are (a) gravitational and bouyant forces (b) centrifugal and drag forces (c) gravitational or centrifugal, bouyant and drag forces (d) external, drag and viscous forces 58. Terminal velocity is (a) a constant velocity with no acceleration (b) a fluctuating velocity (c) attained after moving one-haft of total distance (d) none of these 59. In hindered settling, particles are (a) placed farther from wall (b) not affected by other particles and the wall (c) near each other (d) none of these 60. Drag co-efficient in hindered settling is (a) lesser than in free settling (b) equal to that in free settling (c) not necessarily greater than in free settling (d) greater than free settling 61. For the free settling of a spherical particle through a fluid, the slope of CD – log NRe, plot is (a) 1 (b) –1 (c) 0.5 (d) –0.5

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

62. In continuous fluidization (a) solids are completely entrained (b) the pressure drop less than that for batch fluidisation (c) there is no entrainment of solids (d) velocity of the fluid is very small 63. Pressure drop in fluidized bed reactor is (a) less than that in a similar packed bed reactor (b) more than that in a similar packed bed reactor (c) same as that in a similar packed bed reactor (d) none of these 64. Slugging in a fluidized bed can be avoided by (a) using tall narrow vessel (b) using deep bed solids (c) the proper choice of particle size and by using shallow beds of solids (d) using very large particles 65. Minimum porosity for fluidization is (a) that corresponding to static bed (b) that corresponding to completely fluidized bed (c) the porosity of the bed when true fluidization begins (d) less than that of the static bed 66. In a fluidized bed reactor (a) temperature gradients are very high (b) temperature is more or less uniform (c) hot spot formed (d) segregation of the solids occurs 67. Lower BWG means (a) lower thickness tube (b) lower cross-section of tube (c) outer diameter of tube (d) inner diameter of tube 68. Cavitation occurs in a centrifugal pump when (a) the suction pressure < vapour pressure of the liquid at that temperature (b) the suction pressure > vapour pressure of the liquid at that temperature (c) the suction pressure = vapour pressure (d) the suction pressure = developed head 69. Cavitation can be prevented by (a) suitably designing the pump (b) maintaining the suction head sufficiently greater than the vapour pressure (c) maintaining suction head = developed head (d) maintaining suction head lower than the vapour pressure 70. Priming needed in a (a) reciprocating pump (c) centrifugal pump

(b) gear pump (d) diaphragm pump

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

71. The maximum depth from which a centrifugal pump can draw water (a) dependent on the speed N of the pump (b) dependent on the power of the pump (c) 34 feet (d) 150 feet 72. Boiler feed pump is usually a (a) reciprocating pump (c) multisatge centrifugal pump 73. Plunger pumps are used for (a) higher pressure (c) viscous mass

(b) gear pump (d) diaphragm pump (b) slurries (d) none of these

74. Molten soap mass is transported by a (a) diaphragm pump (b) reciprocating pump (c) gear pump (d) centrifugal pump 75. To handle smaller quantity of fluid at high discharge pressure use (a) reciprocating pump (b) centrifugal pump (c) volute pump (d) rotary vacuum pump

76. The head developed by a centrifugal pump is largely determined by the (a) power of the pump (b) nature of the liquid being pumped (c) angle of the vanes and the speed of the tip of the impeller (d) vapour pressure of the liquid 77. The maximum head that can be developed with a single impeller is (a) 25 ft. (b) 1000 ft. (c) 250 – 300 ft. (d) 1000 ft. 78. A fluid jet discharging from a 2” diameter orifice has a diameter of 1.75” at its vena-contracta. The co-efficient of contraction is (a) 1.3 (b) 0.766 (c) 0.87 (d) none of these 79. The discharge through a V-notch weir varies as (a) H3/2 (b) H1/2 5/2 (c) H (d) none of these 80. The discharge through a rectangular weir varies as (a) H1/2 (b) H3/2 2/5 (c) H (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

81. Propellers are (a) axial flow mixers (b) low speed impeller (c) used for mixing liquids of high viscosity (d) radial flow mixers 82. Turbine impeller (a) produces only radial current (b) produces only tangential current (c) is effective over wide range of viscosities (d) does not produce tangential current 83. With increase in pump speed, its NPSH requirement (a) decreases (b) increases (c) remains unaltered (d) can either increase or decrease, depends on other factors 84. One dimensional flow implies (a) Flow in the straight line (b) steady uniform flow (c) unsteady uniform flow (d) a flow which does not account changes in transverse direction 85. In case of centrifugal fan or blower, the gas capacity varies as (a) spect speed (b) (speed) (c) (speed)3 (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

86. The continuity equation (a) relates mass flow rate along a stream tube (b) relates work and energy (c) stipulates that Newton’s second law of motion must be satisfied at every point in the fluid (d) none of these

87. For a specific centrifugal air blower operating at constant speed and capacity the power requirement and pressure vary (a) directly as squares of gas density (b) directly as gas density (c) directly as square root of density (d) inversely as gas density 88. Foot valves are provided in the suction line of a centrifugal pump to (a) avoid priming every time we start the pump (b) remove the contaminant present in the liquid (c) minimize the fluctuation in dischrarge (d) control the liquid discharge 89. Differential manometer measures

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

(a) atmospheric pressure (b) sub-atmospheric pressure (c) pressure difference between two points (d) none of these 90. Velocity distribution for flow between the fixed parallel plates (a) varies parabolically across the section (b) is constant over the entire cross section (c) is zero at the plates and increases linearly to the midplane (d) none of these 91. While starting a centrifugal pump, its delivery valve should be kept (a) opened (b) closed (c) either opened or closed; it does not make any difference (d) either opened or closed; depending on the fluid viscosity 92. Path followed by water jet issuing from the bottom of a water tank will be a (a) parabola (vertex being at the opening) (b) hyperbolic (c) horizontal straight line (d) zig-zag path (which is geometrically undefined) 93. A centrifugal pump loses prime after starting. The reason of this trouble may be (a) incomplete priming (b) too high a suction lift (c) low available NPSH and air leaks in the suction pipe (d) all ‘a’, ‘b’, and ‘c’ 94. Capacity of a rotary gear pump can be varied by (a) changing the speed of rotation (b) bleeding air into suction (c) bypassing liquid from the suction or discharge line (d) all ‘a’, ‘b’, and ‘c’ 95. For liquid flow through a packed bed, the superficial velocity as compared to average velocity through the channel in the bed is (a) more (b) less (c) equal (d) independent of porosity 96. Reciprocating pumps compared to centrifugal pumps (a) deliver liquid at uniform pressure (b) can handle slurries more efficiently (c) are not subject to air binding (d) can be operated with delivery valve closed

97. A tube is specified by its (a) thickness only (c) thickness and outer diameter both

(b) outer diameter (d) inner diameter

98. For pipes that must be broken at intervals for maintenance, the connector used should be a (a) union (b) tee (c) reduce’s (d) elbow 99. If more than two branches of pipes are to be connected at the same point, then use (a) elbow (b) union (c) tee (d) none of these

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

100. The most economical valve for use with large diameter pipes is (a) butterfly valve (b) globe valve (c) needle valve (d) none of these 101. Which of the following factors does not contribute to the pressure drop in a pipeline? (a) velocity of liquid (b) size of pipe (c) length of pipe and number of bends (d) none of these 102. Which of the following can be used to create a flow of gas where no significant compression is required? (a) reciprocating compressor (b) blower (c) axial flow compressor (d) centrifugal compressor 103. Erosion and pits formation on the impeller of a centrifugal pump may be due to (a) cavitation (b) low speed of impeller (e) its operation with delivery valve closed for considerable time after starting the pump (f) off centering of pump with motor 104. Which of the following valves will incur maximum pressure drop for the same discharge of water? (a) globe valve (b) gate valve (c) needle valve (d) butterfly valve 105. While starting on axial flow pump, its delivery valve should be kept (a) open (b) closed (c) either open or closed (d) none of these 106. Identification of pipelines carrying different liquids and gases is done by (a) diameter of the pipe (b) color of the pipe (c) the altitude of at which pipe is located (d) none of these 107. A centrifugal pump has the following specifications: Power – 4 H.P.; Speed – 800 rpm Head – 8 meters; Flow – 1000 liters/minutes If its speed is halved , then the new head will be (a) 2 m (c) 8 m

(b) 4 m (d) 5.5 m

108. In question No. 107, the power consumed now will be (a) 0.5 H.P. (b) 2 H.P. (c) 4 H.P. (d) 1 H.P. 109. In question No. 107, the new discharge will be (a) 500 liters/min. (b) 200 liter/min (c) 1000 liter/min (d) 750 liter/min

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

110. Interstage coolers are provided in a multistage compressor to (a) save power in compressing a given volume to a given pressure (b) cool the delivered air (c) achieve the exact delivery (d) none of these 111. Surge tanks are provided in high pressure water pipelines to (a) store a definite quantity of water all the time (b) reduce water hammer (c) facilities easy dismantling of pipeline for cleaning and maintenance (d) none of these 112. Pipes having diameter 14 inches or more are designated by their (a) outside diameter (b) inside diameter (c) schedule number (d) none of these 113. Disc compensators are provided in large diameter gas carrying pipelines to (a) keep the pipe in proper orientation (b) make the pipe joint leak-proof (c) account for contraction/ expansion of pipe due to temperature changes of the surroundings (d) account for pressure variation inside the pipelines 114. Nominal Pipe Size (NPS) of a pipe less than 12 inches in diameter indicates its (a) inner diameter (b) outer diameter (c) thickness (d) neither inner or outer 115. The most important factor which determines the maximum height to which water can be lifted by a pump at standard temperature (62F) is (a) barometric pressure (b) speed of the impeller (c) diameter of the impeller (d) both ‘b’ and ‘c’ 116. Bear pump (a) is a positive displacement pump (b) is a centrifugal pump (c) is a non-positive displacement pump (d) can be started with delivery valve closed 117. When the water is warm, the height to which it can be lifted by a pump (a) decreases due to reduced velocity (b) decreases due to reduced vapor pressure (c) increases due to increased vapor pressure (d) decreases due to increased frictional resistance 118. Multistage centrifugal pumps are generally used for (a) high head (b) low head but high discharged (c) highly viscous liquid (d) slurries of high solid concentration

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

119. Centrifugal pump can’t be used to pump (a) molten sodium (used as a coolant in Fast Breeder Reactor) (b) moderately vegetable oil used in soap industry (c) thick molten soap at 80C (d) none of the above 120. Volute type of casing is provided in a centrifugal pump to (a) convert velocity head to pressure head (b) convert pressure head to velocity head (c) reduce the discharge fluctuation (d) increase the discharge 121. A pump operating under specific conditions delivers insufficient quantity of liquid. This may be set right by (a) decreasing the size of the inlet pipe (b) increasing the size of the inlet pipe (c) lowering the pump position (d) both ‘b’ and ‘c’ 122. Delivery of insufficient quantity of liquid by a pump may be caused by (a) air leak in the inlet (b) low rpm (c) too high a lift (d) all ‘a’, ‘b’ and ‘c’ 123. Actual lift of pump always less than the theoretical lift and is limited by (a) specific gravity and temperature of the liquid (b) leakage and pressure decreasing at higher elevations (c) frictional resistance through pipes, fittings and passages (d) all ‘a’, ‘b’ and ‘c’ 124. Fill up the blank Nominal size of the discharge pipe of a pump is usually ……… the nominal size of the inlet pipe (a) smaller than (b) larger than (c) same as (d) twice 125. Horsepower requirement for given pump capacity depends upon the (a) specific gravity of the liquid (b) suction lift (c) discharge head (d) all ‘a’, ‘b’ and ‘c’ 126. What is the enthalphy of steam at 150 psia and 400 OF? a) 1195.2 btu/lbm b) 1220 btu/lbm c) 1250 btu/lbm d) 1275 btu/lbm 127. Which of the following is not true? a) A pump will operate safely if its NPSH is greater than zero. b) Fans and blowers are used to transport gases. c) Pumps and blowers increase the mechanical energy of the fluid. d) The power loss due to friction in a venture meter is greater than in an orifice meter. 128. A pump delivers 40 gpm of water with a total head of 40 ft. The efficiency of the pump is 65%. What is its BHP? a) 0.62 b) 0.70 c) 2.00 d) 5.50 129. A fluid flowing at a rate of 25 m3 per hour in a 60-mm inside diameter pipe has an average velocity in m/s equals to a) 5.9 b) 2.5

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

c) 1.5 d) 0.6 130. The absolute pressure exerted by water 2 m below the surface of a swimming pool is a) 20 kPa b) 120 kPa c) 200 kPa d) 400 kPa 131. Turbulent flow generally occurs for cases involving a) Very viscous fluid b) Very narrow passages or capillary tubes c) Very slow motions d) None of the above 132. A rectangular duct 4 m x 1.5 m in cross-section carries conditioned air. Its equivalent diameter is a) 1.50 m b) 2.18 m c) 2.18 ft d) 2.75 m 133. When the ID of the pipe through which fluid flows is doubled, the pressure loss due to friction per unit length of pipe and for the same volumetric flow rate is changed by approximately a factor of a) 1/8 b) 1/16 c) 1/32 d) 1/64 134. When two centrifugal pumps are connected in series, the discharge changes by factor of a) ½ b) 1 c) 2 d) 4 135. When two reciprocating pumps are connected in parallel, the volumetric capacity of the system changes by a factor of a) ½ b) 1 c) 2 d) 4 136. The pressure drop in a pipeline changes by a factor of a) ½ b) 1 c) 2 d) 4 137. Machines which need electricity to run are a) Generators b) Engines c) Turbines d) Motors 138. Cavitation occurs in a centrifugal pump when a) The discharge pressure becomes too high b) The discharge valve is closed c) Suction is lost d) The suction pressure is too high 139. Oil with viscosity of 30 cP and a density of 60 lbm/ft 3 flows through a ½-inch inside diameter pipe. Determine the velocity in ft/s below which flow will be laminar. a) 87.20 b) 0.63

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

c) 13.10 d) 16.90

140. Water at 60 OF is flowing through a 3-inch inside diameter smooth horizontal pipe. If the Reynolds number is 353,000, calculate the ratio of maximum velocity to average velocity a) 1.89 b) 1.05 c) 1.22 d) 1.72 141. The pressure after the pump in a 6-inch inside diameter smooth pipe conducting water is 20 psia. The water is discharged at an open tank 100 ft from the pump. Calculate the rate of discharge of water in ft3/s. a) 21.0 b) 58.3 c) 0.6 d) 3.58 142. A water storage tank supplies water into a factory. Water is supplied to the tank through a booster pump installed in the water line. The theoretical pump horsepower required is 3.25 hp. What is the monthly operating cost of the pump, if electric power cost on the average is P3.73/kWh. The pump is 65% efficient and operates for 12 hours a day. a) P3300 b) P7000 c) P5000 d) None of the above 143. When the impeller speed of an ideal centrifugal pump is doubled, the volumetric flow rate of the discharge is increased by a factor of a) ½ b) 1.0 c) 2.0 d) 22 144. The differential height between two points where a fluid has to be transferred is the a) Potential head b) Pressure head c) Velocity head d) Dynamic head 145. The bursting pressure of a pipe is directly proportional to its a) Schedule number b) Inside diameter c) Outside diameter d) Length 146. A device for measuring differential pressure is a a) Potentiometer b) Ammeter c) Galvanometer d) Manometer 147. The dimensionless number that characterizes the flow of fluids in a conduit is a) Nusselt number b) Peclet number c) Grashoff number d) Reynolds number

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

148. When a fluid flows through a reducer in a piping system the velocity at the outlet end is ---- the velocity at the inlet a) Less than b) More than c) The same as d) One-half 149. At a given flow rate through an orifice meter the differential pressure across the orifice will increase when. a) The orifice flow area is decreased b) The density of the flowing fluid is decreased c) The orifice flow area is increased d) The thickness of the orifice is decreased 150. The prime mover of a jet pump is a a) Motor b) Fluid momentum c) Turbine d) Engine 151. The weight rate of flow of a fluid stream per unit of cross section perpendicular to the direction of flow is the a) Mean linear velocity b) Acoustic velocity c) Velocity head d) Mean mass velocity of the stream 152. In a reciprocating pump, the ratio of the quantity of liquid actually pumped to that which corresponds to the piston displacement is called a) Hydraulic efficiency b) Mechanical efficiency c) Volumetric efficiency d) Suction lift 153. The schedule number of the pipe is an indicator of the pipe’s a) Outside diameter b) Thickness c) Length per section d) Material of construction 154. The higher the BWG rating of a tube is, the lower is the a) Strength b) Area of flow c) Length of a tube section d) Grade of metal used 155. The inside surface of a pipe has no effect on the friction factor when the flow is a) Turbulent b) Streamline c) Passing through a pump d) By gravity 156. When the movement of a gas vapour is effected at a low pressure say, u to 0.1 kg/cm 2, the equipment used is a a) Compressor b) Blower c) Jet d) Fan 157. Four-inch Sch. 40 steel pipes are to be used to transport high-pressure steam. The pipe joints are to be butt-welded. The safe working fiber stress for butt-welded pipes is 457.1 kg/cm 2. Calculate the maximum steam pressure, in kg/cm2 the pipes can handle. a) 38.2 b) 18.3

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

c) 10.8 d) 150.0

158. The resistance of a layer of fluid to flow over the next layer is measure by a) Viscosity b) Friction factor c) Surface tension d) Momentum 159. Water at 80 OF flows at 10 ft per second through a 6-inch Sch. 40 steel pipe with length of 1000 ft. The Reynolds number is a) 334,000 b) 500,000 c) 255,000 d) 30,000 160. Air is flowing at constant mass rate through a horizontally arranged pipe heater and heated from 70 oF. The pressure is normal at the inlet and the outlet pressure dropped by 1 inch H 2O. The average air velocity at the inlet is 20 ft/s. Assuming that Cp = 0.24 and perfect gas, the net heat input is a) 240 btu/min b) 240 btu c) 240 btu/lbs d) 24 btu/lbs 161. Natural gas at 70 OF is flowing at a steady mass rate through a steel pipe with an inside diameter of 12 inches. Absolute pressure drops from 30 to 15 atm in 400 miles of horizontal pipe. M = 17, µ = 0.01 cP. The volumetric flow rate per hour at 70 OF and normal barometric pressure is a) 8600 ft3 b) 520,000 ft3 c) 8600 m3 d) 23000 ft3 162. Calculate the radius of the capillary tube in mm, such that it is a flow of a viscous fluid. Kinematic viscosity = 0.000043 m2/s Length of tube = 50.2 cm Mass flow rate = 0.003 kg/s Density of the fluid = 955 kg/m3 Pressure drop = 4.77 atm a) b) c) d)

0.32 0.45 0.75 0.18

163. In a high pressure piping system where joints are regularly broken for maintenance, ------ joints are used a) Welded b) Threaded c) Flanged d) Ball and spigot 164. A mechanical vacuum pump that can be used for a final vacuum pressure of 1 mmHg is a) Two-stage reciprocating dry vacuum pump b) Water sealed rotary vacuum pump c) Rotary oil sealed vacuum pump d) Multistage centrifugal pump 165. Air is to be delivered at a rate of 200 cfm and a pressure of 10 kPa. The approximate equipment to use is

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

a) b) c) d)

Fan Blower Compressor Centrifugal pump

166. An axial flow pump operating at a speed of 880 rpm can supply water at a rate of 3000 gpm. The maximum head that this pump can deliver in ft of water is a) 36 b) 63 c) 20 d) None of the above 167. The power requirement of a fan in kW in order to supply air at a rate of 500 m 3/hr at a total discharge pressure of 0.5 psia is ---------- kW. a) 1 b) 0.46 c) 0.85 d) 1.4 168.

Specify the tupe of open impeller pump to use if the capacity is 400 gpm at a head of 200 ft of water --------. a) 3 x 2 x 8.5E b) 4 x 3 x 8.5E c) 4 x 3 x 6.0E d) 3 x 2 x 13.0E

169.

What will be the rated capacity in gpm of a 4-1/2-inch impeller centrifugal pump operating at a speed of 3450 rpm capable of generating a head of 40 ft of water? a) 134 b) 95 c) 248 d) 320

170.

What type of pump would you recommend if the capacity is 5000 gpm at a head of 15 ft of water? a) Gear pump b) Axial flow pump c) Centrifugal pump d) Screw pump

171. What is the entrance length in a 2-inch Sch. 40 pipe if the Reynolds Number is 1800? a) 10 ft b) 8 ft c) 17 ft d) 25 ft 172. If the speed of a centrifugal pump is doubled, the energy requirement becomes approximately ----- times the original energy requirement. a) 2 b) 4 c) 8 d) 10 173. A cylindrical tank 1 ft in diameter discharges through a nozzle connected to the base. Find the time needed for the water level in the tank to drop from 4 ft to 2 ft above the nozzle. The diameter of the nozzle is 1 inch and its discharge coefficient may be taken as unity. a) 42 s b) 21 s c) 30 s d) 15 s

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

174. A pitot tube with a U-tube water manometer is attached to a horizontal oil pipe of 4 in inside diameter. If the manometer reading is 15 in, determine the volumetric flow rate, in gpm, of oil in the pipe. The pitot opening is placed at the center of the pipe. The oil has a specific gravity of 0.84 and a viscosity of 0.0336 lb/ft-sec. a) 77 b) 55 c) 32 d) 94 175.

A sharp differential a) b) c) d)

edged orifice is to be fabricated to measure water flowing at a rate not to exceed 1,200 ft 3/hr, with a head of 10 ft. What orifice diameter in inches is required if D2/D1 is made 1/5? 1 1.5 2 2.5

176. A piping system is conveying 10 ft 3/s of ethanol. At a particular cross section of the system, section 1, the pipe diameter is 12 in, the pressure is 18 lb/in2 and the elevation is 140 ft. At another cross section further downstream, sectioin 2, the pipe diameter is 8 in and the elevation is 106 ft. If there is a head loss of 9 ft between these sections due to pipe friction, what is the pressure at section 2? a) 23 psia b) 35 psia c) 48 psia d) 98 psia 177. An oil has a specific gravity of 0.8000 and a viscosity of 200 SSU (Saybolt Seconds Universal) at 60 OF. Determine the API gravity and Be gravity of this oil at 70 OF. a) 40O API, 25O Be b) 25.4O API, 65O Be c) 15.4O API, 85O Be d) 45.4O API, 45O Be 178. What is the kinematic viscosity in centistokes from #177? a) 24.002 Cst. b) 14.122 Cst. c) 44.225 Cst. d) 74.037 Cst. 179. What is the absolute viscosity in centipoises from #177? a) 100.00 cP b) 970.08 cP c) 11.48 cP d) 35.38 cP 180. Fuel oil at 300 OF and having a specific gravity of 0.850 is pumped through a 30,000 ft long 24-in pipe at the rate of 500 gpm. What is the pressure loss if the viscosity of the oil is cP? a) 1.17 psia b) 5.00 psia c) 10.90 psia d) 15.77 psia

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

181. The figure shows a complex-series pipeline made up of four lengths of different size pipe. Determine the equivalent length of this pipe if each size of pipe has the same friction factor. 1000’

16”

a) b) c) d)

3000’

2000’

12”

8”

10’

4”

2,000 ft 4,040 ft 2,740 ft 6,740 ft

182. A 1000 gpm of water is flowing through a 10-in inside diameter cast-iron water main pipe. The velocity of water flowing is a) 900.1 ft/min b) 344.8 ft/min c) 245.8 ft/min d) 504.9 ft/min 183. What is the hydraulic radius of this pipe when it is full of water from #182? a) 2.0 in b) 0.5 in c) 2.5 in d) 5.1 in 184. The hydraulic radius of the pipe when the water depth is 8 inches using #182. a) 10.0 in b) 91.5 in c) 1.05 in d) 3.04 in 185. Determine the friction-head loss in 25 ft of clean 10-in new tar-dipped cast-iron pipe when 2000 gpm of cold water is flowing. What is the friction-head loss 20 years later? a) 10 ft b) 55 ft c) 102.8 ft d) 250 ft 186. What is the equivalent steam-carrying capacity of a 24-in-inside-diameter pipe in terms of a 10-in inside diameter pipe? a) 15 pipes b) 5.5 pipes c) 9.7 pipes d) 30 pipes 187. Based from #186, what is the equivalent water-carrying capacity of a 23-in inside diameter pipe in terms of a 13.25 in inside diameter pipe? a) 1.5 pipes b) 3.97 pipes c) 5.6 pipes d) 9 pipes

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

188. Dry air at 80 OF and 150 psia flows at the rate of 500 ft 3/min through a 4-in sch. 40 pipe from the discharge of an air compressor. What is the flow rate in pounds per hour? a) 22,620 lbs/hr b) 2,000 lbs/hr c) 1,550 lbs/hr d) 30,000 lbs/hr 189. The air velocity in feet per second from #188? a) 25 ft/s b) 35.8 ft/s c) 95.7 ft/s d) 205 ft/s 190. What is the Reynolds’ number of the air from #188? a) 3,560,000 b) 5,000,000 c) 25,000 d) 3,560 191. Determine the pressure loss if the total equivalent length of the pipe is 500 ft from #188. a) 121 kPa b) 100 kPa c) 90 kPa d) 50 kPa 192. Using the Weymouth formula, determine the flow rate in a 10-mile long 4-in sch. 40 gas pipeline when the inlet pressure is 200 psig, the outlet pressure is 20 psig, the gas has a specific gravity of 0.80, a temperature of 60 OF and the atmospheric pressure is 14.7 psia. a) 5.9 kg/s b) 10.9 kg/s c) 15.7 kg/s d) 30 kg/s 193. Is the acoustic velocity limits the flow based on #192? a) Yes b) No c) Maybe d) I don’t know 194. What is the friction loss in 800 ft of 6-in sch. 40 pipe when 0.025 m 3/s of sulphate paper stock is flowing? The consistency of the sulphate stock is 6%. a) 59 m b) 89 m c) 126 m d) 146 m 195. Determine the pressure loss in 510 ft of 4-in flanged steel pipe containing two 90 O elbows and four 45O bends. The sch. 40 piping conveys 1.64 kg/s of 40-psig- 350 OF superheated steam. a) 150 kPa b) 15.0 kPa c) 279.9 kPa d) 27.9 kPa 196. How much condensate is formed when 2000 lbs of solid material with a specific heat of 1.0 is processed in 15 min at 240 OF by 25-psig steam from an initial temperature of 60 OF in an insulated steel retort? a) 750 kg b) 862.2 kg c) 1,000 kg d) 1,150 kg

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

197. The trap capacity is in #196 wherein the steam is directly heats solid materials, as in autoclaves, retorts and sterilizers a) 3,465 kg/hr b) 5,427 kg/hr c) 2,412 kg/hr d) 678 kg/hr 198. How much condensate forms in the jacket of a kettle when 500 gal of water is heated in 30 min from 72 to 212 OF with 50-psig steam? a) 214 lbs/hr b) 152 lbs/hr c) 15.0 lbs/hr d) 21.4 lbs/hr 199. The trap capacity is in #198 wherein the steam is indirectly heats a liquid heated a metallic surface, as in heat exchangers and kettles where the quantity of liquid heated is known and unknown. a) 65.0 lbs/hr b) 178 lbs/hr c) 650 lbs/hr d) 1,540 lbs/hr 200. How much condensate is formed in a chamber dryer when 1000 lbs of cereal is dried to 750 lbs by 10-psig steam? The initial temperature of the cereal is 60 OF and the final temperature equals that of the steam. a) 40.3 lbs/hr b) 148.9 lbs/hr c) 443.5 lbs/hr d) 689.15 lbs/hr 201. The trap capacity is in #200 wherein the steam is indirectly heats a solid through a metallic surface, as in dryers using cylinders or chambers and platen presses. a) 1,774 lbs/hr b) 1,000 lbs/hr c) 550 lbs/hr d) 89 lbs/hr 202. How much condensate is formed in a unit heater using 10-psig steam if the entering-air temperature is 30 OF and the leaving-air temperature is 130 OF? Air flow is 10,000 ft3/min. a) 41 lbs/hr b) 89 lbs/hr c) 890 lbs/hr d) 1,220 lbs/hr 203. The trap capacity is in #202 wherein the steam is indirectly heats air through metallic surfaces, as in unit heaters, pipe coils and radiators. a) 3,700 lbs/hr b) 2,500 lbs/hr c) 2,000 lbs/hr d) 478 lbs/hr 204. Steam is metered with an orifice meter in a 10-in boiler lead having an internal diameter of d p = 9.760 in. The upstream pressure tap is 1D ahead of the orifice, and the downstream tap is 0.5D past the orifice. Steam pressure at the orifice inlet pp = 250 psig; temperature is 640 OF. A differential gage fitted across the orifice has a maximum range of 12 in of water. Determine the maximum rate of steam flow that can be measured with a steel orifice plate having a diameter of do = 5.855 in at 70 OF. a) 10.75 lbs/s b) 15.75 lbs/s c) 25.75 lbs/s d) 69.05 lbs/s

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

205. Determine the Reynold’s Number for the actual flow rate from #204. a) 1,000 b) 5,897,111 c) 1,750,000 d) 17,500 206. What is the steam flow rate when the observed differential pressure is 40 in of water from #204? a) 2,879 lbs/hr b) 4,178 lbs/hr c) 15,000 lbs/hr d) 32,940 lbs/hr 207. Select a single-seat spring-loaded diaphragm-actuated pressure-reducing valve to deliver 350 lbs/hr of steam at 50 psig when the initial pressure is 225 psig. Also select an intergral pilot-controlled piston-operated single-seat pressure-regulating valve to deliver 30,000 lbs/hr of steam at 40 psig with an initial pressure of 225 psig saturated. What size pipe must be used on the downstream side of the valve to produce a velocity of 10,000 ft/min? a) 17 in b) 5 in c) 26 in d) 8 in 208. How large should the pressure-regulating valve be if the steam entering the valve is at 225 psig and 600 OF from #207? a) 3 in b) 5 in c) 10 in d) 15 in 209. What size pressure-reducing valve should be used to deliver 1200 gph of water at 40 psia if the inlet pressure is 140 psia from #207? a) 0.50 inch b) 1 inch c) 1.50 inches d) 2 inches 210. A centrifugal pump designed for an 1800-rpm operation and a head of 200 ft has a capacity of 3000 gpm with a power input of 175 hp. What effect will a speed reduction to 1200-rpm have on the head, capacity and power input of the pump? a) 8.9 ft; 200 gpm; 5.8 bhp b) 800.1 ft; 2,189 gpm; 51.8 bhp c) 88.9 ft; 2,000,000 gpm; 510.87 bhp d) 88.9 ft; 2,000 gpm; 51.8 bhp 211. What will be the change in these variables if the impeller diameter is reduced from 12 to 10 in while the speed is held constant at 1800 rpm from #210? a) 18.8 ft; 2,500 gpm; 10.2 bhp b) 138.8 ft; 2,500 gpm; 101.2 bhp c) 178.5 ft; 2,500 gpm; 1,001.8 bhp d) 98.8 ft; 2,500 gpm; 781.87 bhp 212. A test-model pump delivers, at its best efficiency point, 500 gpm at a 350 ft head with a required net positive suction head (NPSH) of 10 ft and a power input of 55 hp at 3500 rpm, when using a 10.5-in diameter impeller. Determine the NPSH of the model at 1750 rpm. a) 1.5 ft b) 5.5 ft c) 2.5 ft d) 7.9 ft

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

213. What is the capacity of a full-scale prototype pump with a 20-in impeller operating at 1170 rpm from #212? a) 200 gpm b) 500 gpm c) 1,158 gpm d) 2,487 gpm 214. What are the specific speeds and suction speed of the test-model and prototype pumps from #212? a) 95; 15,900 b) 1,065; 173,900 c) 5,789; 13,900 d) 965; 13,900 215. What is the upper limit of specific speed and capacity of a 1750rpm single-stage double-suction centrifugal pump having a shaft that passes through the impeller eye if it handles clear water4 at 85 OF at sea level at a total head of 280 ft with a 10 ft suction lift? The maximum pump velocity is --------. a) 689 gpm b) 6,040 gpm c) 1,478 gpm d) 4,741 gpm 216. Based from #215, what is the efficiency of the pump and its approximate impeller shape? a) 15% b) 25% c) 50% d) 87% 217. A single-suction centrifugal pump is driven by a 60-Hz ac motor. The pump delivers 10,000 gpm of water at a 100-ft head. The available net positive suction head is 32 ft of water. What is the best operating speed for this pump if the pump operates at its best efficiency point? a) 123 rpm b) 1,597 rpm c) 147.69 rpm d) 1,750 rpm 218. Based from #217, what type of pump is to be used? a) Volute or diffuser b) Turbine c) Mixed-flow d) Axial-flow 219. Compute the total head on each pump if the elevations and the pump discharges a maximum of 2000 gpm of water through 8-inch sch.40 pipe. A swing check valve is used on the pump suction line and a gate valve on the discharge line. a) 15 ft b) 55 ft c) 85 ft d) 147 ft 220. The total piping friction losses is ---- from #219. a) 5 ft b) 2.25 ft c) 14.53 ft d) 12 ft 221. What hp is required to drive the pump from #219? a) 64.1 hp b) 6.4 hp c) 3.25 hp d) 107.89 hp

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

222. These are the types of centrifugal pumps EXCEPT. a) Volute & diffuser b) Regenerative & vertical – turbines c) Mixed & axial flows d) Gear 223. These are the types of rotary pumps EXCEPT. a) Screw & lobe b) Direct - acting c) Cam – and – piston & shuttle - block d) Gear & vane 224. These are the types of reciprocating pumps EXCEPT. a) Direct – acting & diaphragm b) Rotary – piston c) Power (including crank – and - flywheel) d) Cam – and – piston & shuttle – block 225. The following are the characteristics of centrifugal pumps EXCEPT. a) The discharge flow is stead in which has usual maximum suction lift b) The liquids handled are clean, clear; dirty & abrasive when the liquids are with high solids contents c) The discharge pressure range is from low to high d) The usual capacity range is from small to largest available e) All of the above 226. The capacity is ------- if it is affected by the increased head. a) Decreasing b) Increasing c) The same d) No effect with increasing power input 227. The following are the characteristics of rotary pumps EXCEPT. a) The discharge flow is steady in which has usual maximum suction lift b) The liquids handled are viscous & non-abrasive when the liquids are with high solids contents c) The discharge pressure range is only medium d) The usual capacity range is from small to medium e) All of the above 228.

The capacity is ------- if it is affected by the increased head. a) Decreasing b) Increasing c) The same d) No effect with increasing power input

229. The following are the characteristics of reciprocating pumps EXCEPT. a) The discharge flow is pulsating in which has usual maximum suction lift b) The liquids handled are clean & clear c) The discharge pressure range is from low to highest produced d) The usual capacity range is relatively small e) All of the above 230. The capacity is ------- if it is affected by the increased head. a) Decreasing b) Increasing c) The same d) No effect with increasing power input

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

231. What is the maximum capacity of a double-suction condensate pump operating at 1750 rpm if it handles 100 OF water from a hot well in a condenser having an absolute pressure of 2.0 in Hg if the pump centreline is 10 ft below the hot-well liquid level and the friction-head loss in the suction piping and fitting is 5 ft of water? a) 278 gpm b) 508 gpm c) 1,789 gpm d) 659.52 gpm 232. A centrifugal pump handles 220 OF water and has a shutoff head (with closed discharged valve) of 3200 ft. At shutoff head, the pump efficiency is 17% and the input brake hp is 210. What is the minimum safe flow through this pump to prevent overheating at shutoff? a) 30 gpm b) 12 gpm c) 5.69 gpm d) 48 gpm 233. Determine the minimum safe flow if the NPSH is 18.8 ft of water and the liquid specific gravity is 0.995. If the pump contains 500 lbs of water, determine the rate of the temperature rise at shutoff from #232. a) 15.9 gpm b) 62.9 gpm c) 54.29 gpm d) 5.24 gpm 234. If the pump contains 500 lbs of water, determine the rate of the temperature rise at shutoff from #232. a) 10.8 OF/min b) 17.8 OF/min c) 27.9 OF/min d) 37.8 OF/min 235. Select a centrifugal pump to deliver 750 gpm of 1000-SSU oil at a total head of 100 ft. The oil has a specific gravity of 0.90 at the pumping temperature. The water head is -----. a) 19 ft water b) 10.9 ft water c) 1,090 ft water d) 109 ft water 236. The power input to the pump when handling viscous liquids is ------ from #235. a) 33.1 hp b) 3.31 hp c) 331.84 hp d) 789.41 hp 237.

A direct-acting steam-driven reciprocating pump delivers 100 gpm of 70 OF water when operating at 50 strokes/min. How much 2000-SSU crude oil will this pump deliver? a) 50 gpm b) 7 gpm c) 18 gpm d) 80 gpm

238. How much 125 OF water will this pump deliver from #237? a) 15 gpm b) 36 gpm c) 75 gpm d) 108 gpm

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

239. A rotary pump handles 8000-SSU liquid containing 5% concentrated gas and 10% dissolved gas at a 20-inHg pump inlet vacuum. The pump is rated at 1000 gpm when handling gas-free liquids at viscosities less than 600 SSU. What is the output of this pump without slip? a) 4.44 gpm b) 444 gpm c) 44.4 gpm d) 879 gpm 240. Based from #239, what is the output of this pump with 10% slip? a) 399.6 gpm b) 99.6 gpm c) 39.7 gpm d) 3,987 gpm 241. A laboratory vacuum system has a volume of 500 ft 3. Leakage into the system is expected at the rate of 0.00035 ft3/min. What is the backing pump speed, i.e. displacement, should an oil-sealed vacuum pump serving this system have if the pump blocking pressure is 0.150 mmHg and the desired operating pressure is 0.00025 mmHg? a) 1 ft3/min b) 2.5 ft3/min c) 4 ft3/min d) 8 ft3/min 242. What should the speed of the diffusion pump be from #241? a) 133 ft3/min b) 13.3 ft3/min c) 1,897 ft3/min d) 1,330 ft3/min 243.

What pump size is needed for the connecting pipe of the backing pump if it has a displacement or pumping speed of 388 ft3/min at 0.150 mmHg and a length of 15 ft from #241? a) 1 inch b) 2.5 inches c) 5 inches d) 8 inches

244. Gasoline with a density of 50 lb/ft3 is to be siphoned from a tank. The friction loss in the line is F = 0.8 ft-lbf/lbm. Estimate how long it will take to siphon 5 gal, neglecting the change in liquid level in the gasoline tank during this process and assuming that point 1 (at the liquid surface in the gas tank) and point 2 (in the tube just prior to the exit) are at 1 atm? a) 3.12 min b) 2.50 min c) 1.05 min d) 0.25 min 245. Saturated steam at 1 atm is discharged from a turbine at a rate of 1000 kg/hr. Superheated steam at 300 OC and 1 atm is needed as a feed to a heat exchanger. To produce it, the turbine discharge stream is mixed with superheated steam available from a second source at 400 OC and 1 atm. The mixing unit operates adiabatically. Calculate the amount of steam at 300 OC produced. a) 1,012 m3/hr b) 987 m3/hr c) 123.47 m3/hr d) 6,064 m3/hr 246. The required volumetric flow rate of the 400 OC steam is --- from #245. a) 2,956 kg/hr b) 295.6 kg/hr c) 29.5 kg/hr d) 9.5 kg/hr

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

247. A tank holds 100 gals of a water-salt solution in which 4 lbs of salt is dissolved. Water runs into the tank at the rate of 5 gpm and salt solution overflows at the same rate. If the mixing in the tank is adequate to keep the concentration of the salt in the tank uniform at all times, how much salt is in the tank at the end of 50 min? Assume that the density of the salt solution is essentially the same as that of water. a) 0.50 lbs b) 0.33 lbs c) 0.78 lbs d) 1.05 lbs 248. A well-mixed batch reactor wrapped in an electrical heating mantle is charged with a liquid reaction mixture. The reactants must be heated from an initial temperature of 25 OC to 250 OC before the reaction can take place at a measurable rate. Use the data below to determine the time required for this heating to take place. a) 5.78 min b) 53.7 min c) 153.79 min d) 1.58 min 249. Water, density = 1000 kg/m3, flows from a large vessel through a sharp-edged entrance into a pipe at a velocity in the pipe of 2 m/s. The flow is turbulent. Estimate the pressure drop from the vessel into the pipe. a) 100 Pa b) 6,000 Pa c) 1,783 Pa d) 3,456 Pa 250. It is desired to calculate the liquid level in the vessel required to produce a discharge velocity of 2 m/s. The fluid is water at 20 OC with density = 1000 kg/m3 and viscosity = 0.001 Pa.s, and the butterfly valve is at Ø = 10O. The pipe is 2-in sch. 40 with an inner diameter of 0.0525 m. The pipe roughness is 0.046 mm.

1 Z

V2 = 2 m/s

1m 2

90O horizonrL bend a) b) c) d)

0.73 m 1.73 m 6.38 m 10.58 m

251. The Reynolds number is --- from #250. a) 1.05 x 109 b) 1.05 x 1010 c) 1.05 x 104 d) 1.05 x 105 252. The required volumetric flow rate of the 400 OC steam is --- from #245. a) 789 kg/hr b) 526 kg/hr c) 16.32 kg/hr d) 2,956 kg/hr

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

253. Air at þO = 1.5 x 105 and temperature TO = 293 K discharges through a frictionless nozzle to atmospheric pressure. Compute the discharge mass flux at the exit. a) 33.7 kg/m2-s b) 337 kg/m2-s c) 3.37 kg/m2-s d) 1.289 kg/m2-s 254. The exit temperature is --- from #253. a) -11.5 OC b) -1.5 OC c) 25 K d) 472 K 255. The Mach number is --- from #253. a) 1.70 b) 2.98 c) 0.773 d) 0.548 256. The exit velocity is --- from #253. a) 200 m/s b) 20.98 m/s c) 63.98 m/s d) 250 m/s 257. Calculate the discharge rate of air to the atmosphere from a reservoir at 10 6 Pa gauge and 20 OC through 10 m of straight 2-in sch. 40 steel pipe and 3 standard radius, flanged 90 O elbows. Assume 0.5 velocity heads lost for the elbows. a) 1.7 kg/s b) 69.7 kg/s c) 15.8 kg/s d) 2.7 kg/s 258. The pressure ratio is --- from #257. a) 7.89 b) 0.092 c) 1.50 d) 0.25 259. A 3-in sch. 40 is to be used as a distributor for a flow of 0.10 m 3/s of water. The pipe is 0.7 m long and is to have 10 holes of uniform diameter and spacing along the length of the pipe. The distributor pipe is submerged. Calculate the required hole size to limit maldistribution to 5%. a) 5.69 cm b) 15.40 cm c) 1.76 cm d) 89.1 cm 260. The pressure drop across the holes is --- from #259. a) 22,100 Pa b) 2,200 Pa c) 158 Pa d) 15.8 Pa 261. Compute the wave speed rise for instantaneous valve closing with an initial velocity of 2 m/s, in a 4-in sch. 40 steel pipe with elastic modulus 207 x 109 Pa. The liquid is water with ß = 2.2 x 109 Pa. a) 1,365 m/s b) 136.89 m/s c) 1.365 m/s d) 1,782 m/s

DAY 2: CHEMICAL ENGINEERING - FLOW OF FLUIDS Prepared By: Engr. Maureen Jazul Ramos @Feb-1-2007

262. The maximum pressure rise is --- from #261. a) 2.73 X 109 Pa b) 2.73 X 106 Pa c) 2.73 X 107 Pa d) 2.73 X 1015 Pa 263. Based on #261, repeat for a plastic pipe of the same dimensions with E = 1.4 x 109 Pa. The wave speed is ---. a) 456 m/s b) 853 m/s c) 28.2 m/s d) 282 m/s 264. Suppose a selected pump requires a minimum NPSH of 16 ft when pumping cold water. What will be the NPSH limitation to pump propane at 55 OF with a vapour pressure of 100 psi? a) 1 ft b) 5.6 ft c) 18 ft d) 8 ft