Influence of Mach Number and End Wall Cooling on Secondary Flows in a Straight Nozzle Cascade

This paper describes the results of an experimental study of the effect of Mach number and end wall cooling on the secondary flow in a straight nozzle cascade with an aspect ratio of h/c = 0.83. The tests were performed for the outlet Mach numbers M₂ = 0.1, 0.6 and 0.8. The cooling tests are done for one specific cooling configuration consisting of three double rows of injection holes positioned at the leading edge, inside the blade passage and in the throat. The flow was injected into the direction of the free stream direction. The tests are carried out for two cooling mass flow ratios: m˙/m˙_tot = 0.02 and 0.045. The corresponding injection to main flow pressure ratios are: 1.0, 1.16 for M₂ = 0.6 and 1.0, 1.26 for M₂ = 0.8. The flow surveys are made with three-directional pressure probes.