Vortex Generator Jet Flow Control in Highly Loaded Compressors

A flow control method for minimizing losses in a highly loaded compressor blade was analyzed. Passive and active flow control experiments with vortex generator jets were conducted on a seven blade linear compressor cascade to demonstrate the potential application of passive flow control on a highly loaded blade. Passive flow control vortex generator jets use the pressure distribution generated by air flow over the blade profile to drive jets from the pressure side to the suction side. Active flow control was analyzed by pressuring the blade plenum with an auxiliary compressor unit. Active flow control decreased profile losses by approximately 37 % while passive flow control had negligible impact on the profile loss of a highly loaded blade. Passive flow control was able to achieve a jet velocity ratio, jet velocity to upstream velocity, of 0.525. The success of active flow control with a velocity ratio of 0.9 suggests there is potential for passive flow control to be effective. The research presented in this thesis is motivated by the potential savings in the applications of passive flow control in gas turbine axial compressors by increasing the aerodynamic load of each stage. Increased stage loading that is properly controlled can reduce the number of stages required to achieve the desired pressure compression ratio