Effect of diffuser inlet area ratio on free-vortex aerodynamic window performance

The effects of diffuser inlet area ratio on pressure recovery and sealing capability of free-vortex aerodynamic window were investigated experimentally based on active diffuser. The results show that the diffuser inlet area ratio is an important factor influencing the diffuser’s pressure recovery, and the sealing pressure ratio and operation stability of aerodynamic window can be improved by optimizing the ratio. Compared with traditional diffusers, the active diffuser has smaller optimum inlet area ratio, which makes the aerodynamic window jet more closer to the ideal free-vortex jet. The optimum inlet area ratio is approximately 2.03 for active diffuser, under which the critical pressure of the blowing from diffuser’s inner wall is lowest, and the blowing from diffuser’s outer wall al