Effect of Inlet Distortion on the Performance of an Axial Cascade

Abstract-- A cascade is defined as an infinite row of equidis-tant similarly aerofoil bodies. The cascade is used to divert a flow stream with a minimal loss. The flow over an axial cascade pre-sents a complicated intra blade fluid dynamic interaction that causes the flow to behave differently than the flow over a single aerofoil blade. A cascade tunnel in which different shapes of cas-cades could be tested for performance evaluation has been build. An axial flat plate cascade of 70 mm chord, 215 mm span and 0.55 pitch chord ratio has been tested in this tunnel for evaluat-ing its aerodynamic performance. The distortion in the flow ahead of the cascade row was artificially created by using dis-torters of the outer size same as the cross section of the cascade tunnel and were fixed with the help of air tight flanged connec-tions at a location which was four chords ahead of the cascade. The distorters were made from honey comb sheets and were formed into cutouts of four shapes. The present study aims to investigate the effect of inlet flow distortion on the performance of an axial two dimensional cascade. The results depict that the Reynolds number, incidence and blade angle of the cascade con-trol the aerodynamic performance of the axial cascade. Further the experimental values of lift coefficient are less than that ob-tained using theory and the drag coefficients are more than the theoretical values. The aerodynamic parameters of the cascade, deflection, deviation, loss coefficients etc, have been found to depend on both the Reynolds number and the type of distortion. Index Term-- Distortion, performance, cascade, deflection, deviation, drag, lift, coefficient