UNDERSTANDING OF CENTRIFUGAL FAN & BLOWER DESIGN

FEA MODEL OF CENTRIFUGAL FAN IMPELLER

The centrifugal fan is one of the most widely used fans. Centrifugal fans are by far the most prevalent type of fan used in the HVAC industry today. They are usually cheaper than axial fans and simpler in construction. In automotive industries, fans are used for cooling internal combustion engines. It is used in transporting gas or materials and in ventilation system for buildings. They are also used commonly in central heating/cooling systems. They are also well-suited for industrial processes and air pollution control systems.

Centrifugal fans of various descriptions constitute one of several types of turbomachinery, which are used to transfer energy to a flowing fluid. Centrifugal fans are similar in many respects to both centrifugal pumps and
centrifugal compressors. Of course, pumps handle liquids and so can easily be distinguished from fans. But, since fans and compressors both handle gases, their differences are not very distinct. Machines with very low pressure rises are always identified as fans, and those with very high pressure rises as compressors. For intermediate pressure rises, either description can be applied. Even test codes and standards often fail to make a distinction. The flow through centrifugal machines is chiefly radial in the region of energy transfer and is easily distinguished from the flow in axial-flow machines. Axial-flow fans are discussed in the next chapter, but many of the principles of energy transfer given in this chapter are applicable to axial-flow as well as centrifugal fans.