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.
Design & Construction( Cont.)
◎
Figure: Fan blade used in modified design
Problem Explanation: Changed Blade angle was not uniform.
Design & Construction( Cont.)
Final Design: No change in duct Pedestal Fan used
Figure: Finally used fan Blade
Design & Construction( Cont.)
Observations after fan change: Tolerable Backflow Enough pressure and velocity at the test section.
Design & Construction( Cont.)
◎Schematic view of Final Design:
Design & Construction( Cont.)
◎Complete View Of final design:
Design & Construction( Cont.)Fan Blade comparison:
Design & Construction( Cont.)
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
Design & Construction( Cont.)
Figure : Total Duct setup
Design & Construction( Cont.)
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.
Design & Construction( Cont.)
Figure: Fan stand
Design & Construction( Cont.)
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
Taking data for pressure and velocity
Changing fan position
Taking data for pressure and velocity
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
Result and discussion (Cont.)
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
Result and discussion (Cont.)
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
Result and discussion (Cont.)
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 (%
)
Result and discussion (Cont.)
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