Experimental and Numerical Investigation of Rotating Stall Phenomenon in Centrifugal Blower at Different Blade Number of the Impeller

Abstract

Experimental and numerical investigations to study the effect number of blade on the rotating stall phenomenon and pressure fluctuations in centrifugal blower. The experimental test rig which concludes a centrifugal blower, pressure sensors and measurement instrumentations are design and constructed for the present work. A data acquisition system (hardware) and its software have been designed and manufactured to transfer the signal from pressure sensor to the computer and then analysis with time and frequency domain.The experimental study has been carried out by measuring the static pressure variation and pressure fluctuation for three cases of impeller which they different in number of blades (5, 9, 10) and outlet blade angle. Measuring of static values has been completed at various points prepared on the front-wall of the volute casing along one path for three cases of impeller. This path is angular path around the impeller.The experimental results demonstrate that the pressure fluctuations for various mass flow rates are a non-periodical nature and the pressure fluctuations amplitude increase as the mass flow rate decrease. The results indicate that the impeller with nine number of blades demonstrate high pressure fluctuation comparison with other case.Numerical simulation has been carried out on present centrifugal blower to analyze both flow field and pressure fluctuations by using FLUENT 14 package. The numerical simulation has been completed by solving the continuity and momentum equations with moving reference frame technique inside the blower.

Keywords

• rotating stall
• centrifugal blower
• impeller