Experimental and numerical investigation on the shock wave structure alterations and available energy loss variations with a grooved nozzle vane

A passive shock wave control method, using a grooved surface instead of the original smooth surface of a gas turbine nozzle vane to alter a single shock wave into a multiple shock wave structure, is investigated in this paper, so as to gain insight into the flow characteristics of a multiple shock wave system and its variations with various grooved surface geometry parameters. With the combination of numerical and experimental approaches, the shock wave structure and the flow behavior in a linear turbine nozzle channel with different grooved surface configurations were compared and analyzed in details. The numerical and experimental results indicate that the multiple shock wave structure induced by the grooved surface is beneficial for mitigating the intensity of the shock wave, reducing the potential excitation force of the shock wave and decreasing the shock wave loss as well. It was also found that the benefits are related to the geometry of the grooved surface, such as groove width, depth, and number. However, the presence of the grooved surface inevitably causes more viscous boundary layer loss and wake loss, which maybe a bottleneck for general engineering application of such a passive shock wave mitigation method.