STUDY OF SLOPED TRENCH CASING TREATMENT ON PERFORMANCE AND STABILITY OF A TRANSONIC AXIAL COMPRESSOR

摘要

This paper presents a numerical investigation of effects of sloped trench casing treatment over the rotor tip on the aerodynamic performance and stability of a transonic axial compressor rotor (NASA Rotor 37). The axially cutting tip of blade is the marked characteristic of the casing treatment which is differ with casing treatments without adjustment of the blade tip. The numerical method has been verified by experimental results in the case of the smooth casing with the tip clearance of 0.356 mm at the design wheel speed (17188.7 rpm). The simulation results are well consistent with the measurement results. The experiment results of NASA Rotor 37 cite from NASA Lewis Research Center. The simulation results show a performance improvement of the compressor on the sloped trench casing. The flow fields of the smooth and sloped trench casings were compared, and results show the sloped trench geometry provides a barrier to minimize the forward flow from the tip clearance vortex. In addition, the sloped trench allows the forward facing step at the aft end to be replaced by an aerodynamically smooth transition to guide the flow from the recess into the mainstream. These results show a performance improvement of the compressor.