Axial flow fan testing rig

Ahsanullah University Of Science & Technology

Department of MPE

Design and Construction of Axial Flow Fan Testing Rig

Participants Shahib Abrar [11.02.08.034]

Sadia Islam [11.02.08.038] Rakib Hossain [11.02.08.047]

S.M. Asif [11.02.08.056]

Contents:IntroductionLiterature ReviewDesign & ConstructionExperimentResult & DiscussionFuture recommendationConclusion

Introduction

Fan :Imparts small pressure rise to flowing incompressible gas.

Fan Components: 1. Impeller 2.Blades 3.Housing 4.Inlet 5.Outlet 6.Stationary Vanes. Figure: Different Parts of fan

Introduction(Cont.)

Fan Types: Mainly 2 types-

1. Propeller or axial flow fan Propeller fan Fig: Axial Fan mechanism

Tube axial fan

Vane axial fan

Inline centrifugal fan

Introduction (Cont.)Figure: Different Types of Axial fan

Propeller Fan Vane axial fan

Tube axial fan Inline centrifugal fan

Fan types: 2. Centrifugal Fan or Radial Fan

Forward Curved Vane

Backward Curved Vane

Backward Inclined

Radial Tip

Airfoil BladeFig: Propeller fan mechanism

Introduction (Cont.)

Introduction(Cont.)

Figure: Different Types of Propeller Fan

Forward curved vane Backward curved vane Backward inclined

Radial tip Airfoil blade

Objective:

1.Design & construction

2.Testing performance for-

Outside and inside duct fan position

Tip Clearance Various RPM

Literature Review

Year Author Journal/ Article Observation1999 Mark Stevens Fan

PerformanceRated performance is found when flow at inlet is fully developed, symmetrical and free from swirl.

1942 E. Barton Bell Test of A Single Stage Axial Flow Fan

Different blade angles put different effects of flowrate, pressure and efficiency.

1997 F. Kameier and W. Neise

Experimental Study of Tip clearance Looses And Noise in Axial Turbomechanics And Their Reduction.

Reduction in tip clearance will increase the fan performance and reduce the noise.

Literature Review (Cont)

Year Author Journal/ Article Observation

2010 Akturk and Camci

Axial Flow Fan Tip Leakage Flow Control Using Tip Platform Extensions

Reduced tip clearance is related with flow interaction and is essential for improving the energy of the ducted fan system.

2003 R.S. Amano Experimental testing and CFD Simulation of Axial Flow Fan

The maximum pressure occurs close to the tip the blade and the dynamic pressure is found near to hub.

2009 Ahmed F. Abdel and Mostafa Mohammed Ibrahim

Investigation of The Influence of Different Tip Clearance of Compressor Rotor by Computational Analysis.

Blade with zero tip clearance have high pressure ratio and efficiency, increasing tip clearance reduce pressure ratio and efficiency.

“Literature Review(cont)

Joint AMCA 210/ASHRAE 51 Project Committee (1999) Laboratory Method of Testing Fans for Aerodynamic Performance Rating. Arlington Heights, USA: Air Movement and Control Association International, Inc.

The Basics of Axial Flow Fans (2000). Hudson Product Corporation.

Design & construction:

Two sectors- 1. Fan selection 2. Duct design

Design description- As we had to change or design for several times for description purpose we divided it into three stages:

1. Initial Design 2.Modified Design 3.Final Design

Design & Construction (Cont.)

1.Initial Design: Fan Selection: 3 criteria has been considered-

1.Blade to blade diameter2.Built in pressure3. Air flow rate

Selected fan: Figure: Initially selected fan blade

Model :F(T)AC4-40 Flow rate= 65 m3/s Velocity: 26.21 m/s

Design & Construction( Cont.)

Duct: Total length= 11 feet 3 inch Test section width & height= 8 inch

Problems in this design: Insufficient air flow and pressure in test section.

Reason: Large Amount of backflow.

Problem Explanation: Backflow is related with two terms- 1. Blade width 2. Blade angle

Design & Construction( Cont.)Modified design: 2 major changes-

Increase in duct length by 2 feet at duct entry-- Air will enter in the duct more uniformly

Fan blade change ( 4 blade)--Used less angle blade

Problems in this design: Still there is not enough pressure and velocity in test section.

Reason: Still there was a backflow.


◎

Figure: Fan blade used in modified design

Problem Explanation: Changed Blade angle was not uniform.


Final Design: No change in duct Pedestal Fan used

Figure: Finally used fan Blade


Observations after fan change: Tolerable Backflow Enough pressure and velocity at the test section.


◎Schematic view of Final Design:


◎Complete View Of final design:

Design & Construction( Cont.)Fan Blade comparison:


Apparatus: 1. Duct: Length 13 feet 3 inch Steel Sheet thickness 1.2 mm

Three segments of the duct-

I. Inlet portion- round ,22 inch diameter, 3feet long.II. Converging portion- 3feet 4 inch longIII. Rectangular portion ( Test section)- Around 7 feet long.

2. Duct stand: Height-3 feet, length-10 feet 3 inch.

3.Ring


Figure : Total Duct setup


4. Pedestal Fan-Blade- 18 Inch diameter

5.Fan Stand:2 portions- 1. Vertical portion 2. L-shape portion

Vertical portion Can vary height , Range 3feet to 4 feet.

L-shape portion contains Horizontal section- 3feet long, helps to enter fan in duct.

Plays important role in fan alignment.


Figure: Fan stand


6.Regulator: Vary RPM (1440, 1410, 1395,1380 RPM)

7.Gasket: 4 set 0.5 inch of thickness 6 inch width

8. Pressure Flow meter : Static pressure , dynamic pressure , velocity is measured

9.Tachometer

10. Multimeter

Experiment

Several experiments have been done can be classified in to three cases

•Fan position: Outside the duct

Case one

•Fan position: Inside the duct

Case two

•Fan position: Inside the with variable tip clearance

Case three

Experiment (Cont.)

Figure: Various fan position point during experiment

Experiment (Cont.)

Steps of experiment procedure for case one and case two

Measuring voltage

current of fan

Taking data for pressure and velocity

Changing RPM

Measuring voltage

current of fan


Changing fan position


Fan alignment

Experiment (Cont.)

Steps of experiment procedure for case three

Fan alignment

Taking data for velocity and pressure

Varying tip clearance

Taking data for velocity and pressure

Experiment (Cont.)

Observations:

Velocity and pressure profile for all three cases.

Variation of average flow rate and velocity for different fan position for case one and

case two.

Variation of average flow rate for different RPM for all three cases.

Variation of friction factor for different RPM of fan for case two.

Variation of flow rate for different tip clearance for case three.

Variation of efficiency for different RPM for case all three cases.

Result and discussion

Observation of velocity profile for case one ( fan position 6 inch outside the

duct)

Figure: velocity profile for case one

Result and discussion (Cont.)

Observation of pressure profile for case two (fan position: 3 feet inside the

duct)

Figure : Pressure profile for case one

0 5 10 15 20 250

0.10.20.30.40.50.60.70.8

Pressure profile

P at 0.675

P at 0.7814

P at 0.887

P at 1

Pressure. Pa

Hei

ght


Observation of flow rate for different fan position inside the duct

Figure: Flow rate Vs Fan position

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.40.12

0.14

0.16

0.18

Flowrate Vs Fan position

Q for 1440

Fan position

Flow

rate

Result and discussion(Cont.)

Observation of flow rate for different RPM ( Fan position : inside the duct)

Figure : Flow rate Vs RPM

1370 1380 1390 1400 1410 1420 1430 1440 14500.11

0.12

0.13

0.14

0.15

0.16

0.17

Flowrate Vs RPM

Q at 0.675

Q at 0.7814

Q at 0.887

Q at 1

RPM

Flow

Rat

e


Observation of friction factor for different RPM ( fan position: inside the duct)

Figure : Friction factor Vs RPM

1370 1380 1390 1400 1410 1420 1430 1440 14500

0.01

0.02

0.03

0.04

0.05

Friction factor Vs RPM

For 18 inch inside...

RPM

Fric

tion

Fact

or


Observation of efficiency for different RPM ( for case three)

Figure: Efficiency Vs RPM

1370 1380 1390 1400 1410 1420 1430 1440 14500

2

4

6

8

10

Efficiency vs RPM

Efficiency

RPM

Effi

cien

cy (%

)


Observation of flow rate for different tip clearance (fan position: two

feet inside the duct)

Figure : Flow rate Vs Tip clearance

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.60.13

0.15

0.17

0.19

0.21

0.23

0.25

Flowrate Vs Tip clearance

RPM 1380RPM 1395RPM 1410RPM 1440

Tip Clearance, Inch

Flow

rate

,m³/s

Future Recommendation ◎

► Material selection ► Alignment of fan ► Fan selection ► Flow straighter

Conclusion

The test rig is mainly constructed for Laboratory purpose of Ahsanullah University of Science and Technology.

We are grateful and thankful to have the supervision under honorable Dr. Dewan Hasan Ahmed.

THANK YOU

Axial flow fan testing rig

Engineering

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