International Journal of
Engineering Science and Futuristic Technology A Peer-reviewed journal ISSN : 2454-1125 IJESFT 01 (2015) 001-009
Comparison of backward curved impeller with backward inclined Airofoil of Centrifugal fan S P Dayal * Department of Mechanical Engineering, Government Polytechnic, Vadnagar, Gujarat, India
ABSTRACT:
The main objective of this paper is to show Comparison of backward curved impeller with backward inclined Airofoil of Centrifugal fan. The best efficiency points at different speeds were obtained. The produced static pressure and air volume at best efficiency points were recorded. Results were plotted as fan characteristic curve and conclusion has been made.
© 2015 A D Publication. All rights reserved
Keywords: 1.
Centrifugal fan ,backward curved impeller , backward inclined airofoil
Introduction
Now a day in every textile spinning application waste evacuation is being done by continuous waste removal process. The waste which is generated in preceding machines is being collected and guided through the duct system to the filtering unit. The filtering unit comprises of different types of fan. i.e. Waste handling fan, Dust handling fan, Clean air/Main fan etc. Filter unit is heart of the textile mill as the breakdown in Filter unit leads to shutdown of the complete spinning line results into huge losses in production hours. The Main Fan is the heart of the Filtering unit. The function of the Main fan is to create required suction pressure at given waste volume to each machine. The losses because of the ducting lengths, bends, surface roughness etc needs to be considered while project planning. So the input for this project is to design the complete main centrifugal fan which can handle -2000 Pa static pressure at 30000 m³/Hr air volume with optimum power consumption According to their blade shapes, centrifugal fans can be subdivided into the following six categories: AF (airfoil), BC(backward-curved). BI (backward inclined), RT(radial tip),FC(forward curved) and RB(radial blade). These six commonly used blade shapes. Each of them has its own advantages and disadvantages. Accordingly each is well suited for certain applications. Many fans, however, are built for low cost and have maximum efficiencies below those shown, and occasionally – as we will see- even higher efficiencies are obtained with BI and RT blades. The highest efficiencies can be obtained with airfoil blades, the lowest with radial blades. There are six types of centrifugal fan wheel in common use according to the types of blades. Centrifugal fan with AF blades has the best mechanical efficiency and the lowest noise level (For comparable tip speed) of all centrifugal fans. Cast aluminium AF blades are often used in small sizes and for testing development work. Centrifugal fan with BC blades are having single thickness otherwise are similar to AF blades with respect to construction and performances. They have slightly lower efficiencies but can handle contaminated air streams because the single-thickness steel blades can be made of heavier material than can be used for hollow airfoil blades. Centrifugal fans with BI blades are economical in production, but they are somewhat lower in structural strength and efficiency. Centrifugal fan wheels also can be used without scroll housing, in such applications as unhoused plug fans, multistage units and roof ventilators. Centrifugal fans with RT blades are curved, with good flow conditions at the leading edge. These RT wheels *
Corresponding author e-mail: swatidayal@rediffmail.com
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