DDES study on a pressure-side cutback cooling turbine blade with a whisker lip and a whisker trailing edge

Abstract

In this study, the whisker structure of a harbor seal is applied to the lip and the trailing edge of a turbine cooling blade with a pressure-side cutback. Four cases are studied in this article, including a prototype, a whisker trailing edge, a PP (The lip’s peak and the trailing edge’s peak are designed at the same blade height) case, and a PV (The lip’s peak and the trailing edge’s valley are designed at the same blade height) case. The DDES method is used to simulate the flow and thermal mixing process in the cascade. The coolant mass flow ratios ($c_m$) of 0.5% and 1% at an outlet Mach number of 0.9 are simulated. The PP case can achieve the best aerodynamic performance, which reduces the thermodynamic energy loss coefficient of the prototype by 0.98% and 0.99% at $c_m$ = 0.5% and $c_m$ = 1%, respectively. The PP case and the PV case increase the lowest spanwise average adiabatic film cooling effectiveness on the cutback surface from 0.5 to 0.7 at $c_m$ = 0.5%. The film cooling effectiveness of the PP case and the PV case can remain close to 1 over the entire cutback surface at $c_m$ = 1%. The PP case transforms the trailing edge shedding vortices on the pressure side into hairpin vortices. The whisker lip suppresses the lip vortex and alters the closed separation bubble on the cutback surface, causing the coolant to converge toward Section 1. The convergence of coolant is more helpful for the PP case to control the pressure side shedding vortex, resulting in a lower thermodynamic energy loss.

Keywords:

• Film cooling
• turbine blade
• vortex shedding
• whisker structure

Declaration of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Additional information

Funding

The authors acknowledge financial support from the Natural Major Science and Technology Project of China (No. 2017-I-0005-0006) and the Outstanding Youth Science Foundation of Heilongjiang Province of China (No. YQ2020E016).