EFFECT OF LOCALIZED BLADE ROUGHNESS WITH DIFFERENT VELOCITIES IN AN AXIAL FLOW COMPRESSOR CASCADE

Abstract

A computational study has been conducted for different inlet velocities in linear axial flow Compressor Cascade focusing mainly on analysis of the effect of Localized blade roughness with different velocities on the aerodynamic performance of the Cascade. Measurement of pressure loss was carried out for various values of velocities with different Localized roughness on the blades of Cascade because the roughness on the blade surfaces can never be same. Except this the effect of different inlet velocities on pressure losses are also analyzed. The Gambit 2.4.6® was used for creating geometry and computational fluid dynamics (CFD) commercial software FLUENT 6.2.16 was used to solve the governing equations. Initially, both surfaces of the blades of the cascade are kept as smooth and total pressure loss is analyzed for the different velocities like 250m/s, 300m/s and 350m/s. Then Suction surfaces and Pressure surfaces are kept as smooth separately for the inlet velocities 250m/s, 300m/s and 350m/s and Percentage profile losses are found. Then Suction and Pressure surfaces are divided into three equal parts and different roughnesses are given on the surfaces and % Profile losses are found for different inlet velocities as 250m/s, 300m/s, and 350m/s. It is observed that for the smooth and rough blades Profile loss reduced with the increase of inlet velocity but this reduction in Profile losses is very less. But with the Localized roughness the Profile loss changes considerably. It is observed that Profile loss in case of Smooth blades for the inlet velocity from 250 m/s to 300 m/s is reduced by 7.02 %. For the wholly rough, only suction surface rough and only pressure surface rough Profile loss for the same inlet velocity increase is reduced by about 6.98 %. In case of localized roughness profile loss reduced by about 3.6 %.