59821 - Analysis and Design of Radial Blowers for the Pressure Ratio Range 1.2 -1.8 

Radial compressor design in the range of pressure ratio 2.0 - 4.0 have a well-established guideline for most common gases, and it is possible to determine optimum compressor geometry for various applications as characterized by specific speed or flow coefficient. Specific speed can be correlated to various combinations of inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, blade exit back-sweep, and inlet-tip absolute tangential velocity for solid body pre-whirl. For Radial Compressor in the pressure ratio range of 1.2 - 1.8, also known as Blowers, there is no organized and systematic optimum design data. Blowers, among many others uses, are widely used in HVAC and provide air for ventilation and industrial process requirements. Blowers are a very important group of turbomachinery. This paper will provide analysis and design data for blowers in the Pressure Ratio range 1.2 -1.8. The data provided, using specific speed will be correlated with reasonable accuracy to possible achievable maximum efficiencies with a good operational range. Furthermore plots of impeller exit flow angle, inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, head coefficient, and blade exit back-sweep will be provided over a range of specific speeds for various tip speeds to permit rapid selection of optimum blower size and shape for a variety of applications. The design procedure will follow a method that will allow efficient blade passage sizing. When the blower inlet and outlet velocities, diameters, blade widths, and blade angles are determined and fixed; after applying the energy, momentum, and continuity balance analysis, the blade passage and profile will be sized to influence the proper pressure and velocity distribution throughout the blower impeller.  Generally, the passage will be designed to accommodate optimum prescribed diffusion rate.