osbourne reynold

ABSTRACT

Aims of this experiment is to observe the characteristic of the flow of fluid in pipe, which may be laminar, transition or turbulent pipe flow by measuring the Reynolds number and the  behavior of the flow.

In order to determine that the flow is laminar, transitional, or turbulent, the value of  ‘Reynolds number’ ( Re)  Re) has to be determined. Laminar and turbulent flow are most common in  Re is flow regimes or in liquid flow measurement operations but there is also transitional flow. If  Re high (>4000), inertial forces dominate viscous forces and the flow is turbulent; if  Re if  Re number is low < 2300), viscous forces dominate and the flow is laminar. Other than that, the dye injections that were supposed to be use in the experiment can clearly show the behavior of the flow, but it cannot be used as the apparatus are running out of dye.

The experiment involves running the Osborne Reynolds equipment with different volume flow rates of water. In this experiment we fix the volume, which is 4×10-3 m3. Time is taken when the volume reached the fix volume. At the same time the characteristics of the flow are observed whether it is laminar, transition and turbulent flow. From the data collected, calculation is made to estimate the range for laminar, transition and turbulent flow. In proving that the Reynolds number is dimensionless, the calculation is made by using the units only and using the appropriate formula. It is proved that the Reynolds number is dimensionless.

APPARATUS 1. The F1-10 Hydraulics bench allow to measure flow by timed volume collection. (Figure A)

Figure A: F1-10 Hydraulic Bench [1]

2.

The F1-20 Reynolds’ Apparatus (Figure B)

Figure B: The F1-20 Reynolds’ Apparatus [2] 3. A stopwatch to allow us to determine the flow rate of water.

PROCEDURES 1. The Reynolds apparatus has been position on the fixed, vibration-free surface (not the hydraulic bench) and the base had been ensure horizontal. This apparatus has been set up  by the technician before experiment start. 2. The pump started. System is allowed to fill with water by slightly open the apparatus flow control valve, then the bench valve opened. 3. The bench control valve was adjusted to produce a low overflow rate to avoid the water  level reaches the overflow tube. 4. The initial height of water level in head tank is set to be 15.5 cm. This height is just for  reference level for the next procedure. 5. The flow increased by opening the apparatus flow control valve. Flow of the water let to stabilize then level of water level in head tank recorded. 6. The collection of 4 liters of water in the volumetric tank is timed and recorded by closing the ball valve which acts as a stopper to prevent the tank outflow. 7. The ball valve is re-opened after taking the measurements. 8. The experiment is repeated for another 3 varies height of water level.

CALCULATIONS

 Flow Rate Q ,t 

Qt =

V

=

t

Volume Collected Time for Collection

1 m3 = 1000 L 4 L = 0.004 m3

Qt =

0.004m3 66s

= 6.0606 × 10-5 m3/s

Velocity,

v

= Flow Rate Area of Pipe

Area of Pipe = 7.854 × 10-5 m2

v

= 6.0606 × 10-5 m3/s 7.854 × 10-5 m2

= 0.7717 m/s

 Reynolds number,

Reynolds Number, Re = velocity × diameter  Viscosity

At 25 ºC the kinematic viscosity of water is = 0 .893 x 10-6 m2/s

Diameter = 0.01 m

Re = 0.7717 m/s s x 0.01m 0.893 x 10-6 m2/s

= 8641.6573

All data are repeatedly calculated for every time taken,

Laminar Flow: Re