Numerical Investigation on Flow Field Characteristics of Linear Cascade with Spontaneous Tip Injection

The flow field of a linear cascade with single-hole spontaneous tip injection (STI) was obtained by numerically solving relevant three-dimensional Reynolds-averaged N-S equations (RANS), after which the flow interaction between tip injection flow and tip leakage flow (TLF) was analyzed, while the characteristics of both tip leakage and blade load distribution were compared under conditions with and without tip injection, and the influence of relative endwall movement on tip leakage flow with STI was discussed. Results show that the fan-shaped low velocity zone downstream the jet orifice occupies part of the leakage flow passage, which produces a suppression effect on the tip leakage flow and influences the blade load distribution in the meanwhile. Compared with the case without STI, when the Reynolds number is 5.764×105, the relative leakage ratio will reduce by 5.42% and the load of single blade will increase by 1.41%, under the condition with STI.