Numerical Analysis of the Effects of Rotor Tip Injection on Axial Compressor Aerodynamics and Performance

摘要

Detailed numerical investigations have been conducted in regard to the effects of rotating tip clearance injection on aerodynamics and performance of a single stage axial compressor. The axial compressor stage was designed for the implementation of an internal convective rotor cooling system with tip injection. The correlations between the blockage generation as well as the performance parameters and the injection geometry design have been clarified for a variation of the injection mass flow rate. The simulations have been performed utilizing a 3D-Reynolds Averaged Navier-Stokes Solver and high-resolution hexahedron meshes. Multiple injection mass flow rates were simulated to reveal the correlations for the performance quantities. For smaller injection mass flow rates the isentropic efficiency decreases almost linear, further increase of injection mass flow rate leads to an exponential decrease of the isentropic efficiency. These two identified regimes are separated by a transition point. By a detailed aerodynamic analysis the main geometric parameters influencing the location of the transition point have been identified. Based on these findings geometrical modifications of the injection geometry were found, which result in a significant gain in injection mass flow rate at comparable compressor performance.