An experimental investigation of secondary flow in a low aspect ratio impulse cascade at different inlet flow angles

The paper describes the effect of incidence angle on the three-dimensional flow in a linear large scale impulse cascade. The blade chord length in the experiment was 500 mm. The results are presented for a blade aspect ratio of 0.8 and incidence angles of -14.4 degrees, -0.6 degrees and +8.6, The details of the 3D flow were examined at five planes within the blade passage and at one plane behind the trailing edge. The 3D flow field has been obtained by traversing a 4 mm spherical fivehole probe. The flow details are presented in terms of loss coefficient, axial vorticity, secondary velocity and flow angles. The mass averaged results are presented in terms of spanwise distribution of loss coefficient, secondary flow angle deviation and growth of the loss through the cascade. The test results includes static pressure measurements over the whole blade surface. These show the 3D flow development on the blade under various incidence angles.