Centrifugal_Blower_Test_rig.pdf

Foreword Welcome to value-conscious company. We are proud of the advanced engineering and quality construction of each equipment we manufacture. This manual explains the working of equipment. Please read it thoroughly and have all the occupants follow the instructions carefully. Doing so will help you enjoy many years of safe and trouble free operation. When it comes to service remember that K.C. Engineers knows your equipment best and is interested in your complete satisfaction. We will provide the quality maintenance and any other assistance you may require. All the information and specifications in this manual are current at the time of printing. However, Because of K.C. Engineers policy of continual product improvement we reserve the right to make changes at any time without notice. Please note that this manual explains all about the equipment including options. Therefore you may find some explanations for options not installed on your equipment. You must follow the instructions and maintenance instructions given in the manual carefully to avoid possible injury or damage. Proper maintenance will help ensure maximum performance, greater reliability and longer life for the product.

K.C. Engineers

Centrifugal Blower Test Rig

Contents

1.

Objective

……………………………………

1

2.

Aim

……………………………………

1

3.

Introduction

……………………………………

1

4.

Theory

……………………………………

1

5.

Description

……………………………………

1

6.

Utilities Required

……………………………………

2

7.

Experimental Procedure

……………………………………

2

8.

Observation & Calculation

……………………………………

3

9.

Nomenclature

……………………………………

4

10.

Precautions & Maintenance Instructions ……………………………………

5

11

Troubleshooting

……………………………………

5

12.

References

……………………………………

5

Centrifugal Blower Test Rig

CENTRIFUGAL BLOWER TEST RIG (D.C)

1.

OBJECTIVE: To study the effect of forward, backward and radial curved vanes.

2.

AIM: To find out the discharge, head & overall efficiency of the Centrifugal blower. To plot the graphs
Efficiency vs. Discharge
Head vs. Discharge

3.

INTRODUCTION: Blowers are used in furnaces, cupolas, mine and air-conditioning plants etc. There can be three different types of impellers namely Radial Curved Vane, Forward Curve Vane, and Backward Curve Vane.

4.

THEORY: Blowers are used to discharge higher volume of air at low pressure. They consist of impeller and spiral casing. They are used in furnaces, cupolas, mine and airconditioning plants etc. There can be three different types of impellers namely Radial Curved Vane, Forward Curve Vane, and Backward Curve Vane. Impellers may be made of sheets and can be casted. Motor rotates the impeller and impeller sucks the air through the center and delivers the air through its periphery. Velocity, discharge and head depend upon the outlet, inlet angles and peripheral speed.

5.

DESCRIPTION: Blower consists of a motor, impeller and its body. Three impellers i.e. forward curved, backward curved and radial curved vane is provided with the set-up. These are interchangeable and any one of then can be fixed on the motor shaft. To find out the outlet velocity, the Pitot tube is provided. Differential manometer is fixed to find out the difference of pressure of Pitot tube at Blower outlet. Energy meter is provided to find out the input power to blower. For changing the discharge and head, valve is provided at outlet of the air. IDENTIFICATION OF IMPELLERS:

 Backward curved impellers are identified by Black color.

Centrifugal Blower Test Rig

1

 Radial curved impellers are identified by Red color.  Forward curved impellers are identified by Yellow color.

6.

UTILITIES REQUIRED: Electricity Supply: Single Phase, 220 V AC, 50 Hz, 5-15 amp socket with earth connection. Bench Area Required: 2.5 m x 0 .5 m

7.

EXPERIMENTAL PROCEDURE: STARTING PROCEDURE:

1. Clean the apparatus and make it free from Dust. 2. Fill manometer fluid in manometer Tube i.e. water. 3. Fix the Impeller on the blower desired one (Radial, Backward or Forward Curve Vane). 4. Ensure that all On/Off Switches given on the Panel are at OFF position. Now switch ON the Main Power Supply. 5. Switch ON the Blower. 6. Fix the RPM of motor with the help of DC Drive and read the RPM of motor with the help of RPM Indicator provided on the Panel. 7. Control the flow of air with the help of control valve provided in the discharge pipe. 8. Measure the pressure difference, static head & dynamic head with the help of manometer. 9. Record the power consumption by means of energy meter, provided in panel using Stop Watch. 10. Repeat the same experiment for constant RPM but change the flow of air with the help of control valve and then for different RPM. 11. When experiment on first particular Impeller is over, fix other desired Impeller on Blower and start experiment. CLOSING PROCEDURE:

1. When experiment is over, adjust DC Drive knob at ZERO. 2. Switch OFF the Blower. 3. Switch OFF Power Supply to Panel.

Centrifugal Blower Test Rig

2

8.

OBSERVATION & CALCULATION: DATA: g

=

9.81 m/s2

ρa

=

1.21 kg/m3

ρw

=

1000 kg/m3

Cv

=

0.98

ηmotor =

0.8

D

0.069 m.

=

OBSERVATION TABLE: N,

Opening

RPM

h11,

h12,

h21,

h22,

R1 ,

R2 ,

cm

cm

cm

cm

cm

cm

p

tP, sec

Full open ¾ Open ½ Open ¼ Open

CALCULATIONS: Ei =

p 3600 , kW × t P EMC

E S = Ei × η m , kW

= --------------- kW = --------------- kW

h1 =

h11 − h12 ,m 100

= --------------- m

h2 =

h21 − h22 ,m 100

= --------------- m

R=

R1 − R2 ,m 100

= --------------- m

 ρ H = (h1 + h2 ) w − 1 , m of air   ρa

= --------------- m of air

V = C v 2 gh , m/sec

= --------------- m/sec

Centrifugal Blower Test Rig

3

 ρ h = R w − 1 , m of air   ρa

= --------------- m

Q = V × A , m3/sec

= --------------- m3/sec

Eo =

9.

ρa × g × H × Q 1000

, kW

= --------------- kW

ηB =

Eo × 100 % ES

= --------------- %

ηo =

Eo × 100 % Ei

= --------------- %

NOMENCLATURE: A

=

Area of cross section of pipe, m2.

Cv

=

Co-efficient of Pitot tube.

D

=

Diameter of pipe, m.

Ei

=

Power input, kW.

Eo

=

Power output, kW.

ES

=

Shaft power, kW.

EMC

=

Energy Meter Constant, Pulses/kW hr.

g

=

Acceleration due to gravity, m/sec2.

H

=

Total Head, m of air.

h1

=

Static Head, m.

h2

=

Dynamic Head, m

N

=

Speed of Blower, RPM.

P

=

Pulses of energy meter

Q

=

Discharge, m3/sec.

R1, R2

=

Differential Pressure Manometer reading, cm.

tP

=

Time taken by P, sec.

V

=

Velocity of Air, m/sec.

ρa

=

Density of Air, kg/m3.

ρw

=

Density of Water, kg/m3.

ηm

=

Efficiency of motor %.

ηB

=

Efficiency of blower %.

ηo

=

Overall efficiency %.

h11 & h12

=

Low Pressure Manometer Reading, cm.

Centrifugal Blower Test Rig

4

h21 & h22

=

High pressure Manometer Reading, cm.

10. PRECAUTIONS & MAINTENANCE INSTRUCTIONS: 1. Always keep apparatus free from dust.

11. TROUBLESHOOTING: 1. If blower is not blowing the air, revolution of the motor may be reverse. Change the electric connection of motor to change the revolutions. 2. If panel is not showing input, check the main supply.

12. REFERENCES: 1.

Streeter, Wylie, Bedford, “Fluid Mechanics”, 9th ed., McGraw Hill., NY, 2007, Page 522-527.

Centrifugal Blower Test Rig

5