自循环机匣周向偏置对轴流压气机非定常流场的影响

NASA Rotor 35 is taken as the research object, three kinds of self-recirculating casings with different circumferential offset degrees (positive 15°, 0° and negative 15°) are set up, and three-dimensional unsteady value simulation is carried out by using NUMECA software package to study the influence of casing treatment on unsteady flow field of compressor. The numerical simulation results show that for the stall of NASA Rotor 35 caused by the interaction of passage shock and tip leakage vortex, the different circumferential offset angles of the self-recirculating casing treatment can better expand the compressor stability to varying degrees, almost no penalty to compressor peak efficiency. The self-recirculating device in which the circumferential offset is 15° is the best of stall margin improvement (SMI), but the total pressure ratio of the compressor is obviously reduced. The SMI ability of the self-recirculating device after circumferential offset no longer follows the traditional empirical rule that stabilization effect is correlated with the circulating flow rate, the injector outlet speed and the flow loss in the self-recirculating device, but is caused by the unsteady processes of self-recirculating device and flow field coupling. The suction and jet action on the tip flow field causes the static pressure distribution and the tip leakage flow to periodically fluctuate, and there are phase delays at different physical quantity peaks.