Computational Studies on the Flow Aspects Through the Nozzle in Case of a Counter Rotating Gas Turbine Stage

Gas turbines are prominently used these days in both power generation and transportation in view of faster depletion of conventional fuels. Flow in a turbine stage is complex and in case of counter rotation turbine, it is still high. This work involves computationally investigating the flow aspect in case of inlet guide vane, i.e. nozzle. Turbine stage components, nozzle and the two rotors are modelled and meshed. Validation is done with experiments done earlier. Transient planes are taken at nearly six locations of the nozzle blade passage. Total pressure and velocity in stationery frame, entropy, turbulent kinetic energy and secondary velocity contours are drawn to have proper understanding of the flow through nozzle. Flow impingement is good at the leading edge of the nozzle and there is development of tip and hub side boundary layer losses after the mid-chord segment. Overall pressure change is less as expected and absolute velocity component is increasing in the nozzle. Secondary velocity contours are drawn to observe any flow separation or circulation, which is not present in the nozzle passage. Thus, flow in nozzle is thoroughly captured, which is found as different from cascade flows as predicted in earlier researchers through experiments.