Research on Variable Hetz Airflow Expansion Channel Based on Rocket Sled
The application of airflow expansion channel device in rocket sled test can obtain higher airflow velocity at the exit,so as to realize the simulation of hypersonic environment. The design and numerical simulation of airflow channel device for rocket sled are studied. Firstly,the internal part of the air expansion channel is divided into initial source flow expansion area,wave attenuation area and uniform flow test area. Foelsch method is used to design the initial expansion section profile,and the characteristic method based on the preset Mach number of the axis is used to design the transition wave attenuation band. On this basis,numerical simulation analysis is carried out for the rocket sled air expander with a growth rate of 2. 5 at the operating speeds of 1. 5Ma,2Ma,2. 5Ma and 3Ma. The results showed that the expansion wave at the inlet of the channel weakened with the increase of the operating speed. The peak relative pressure at 1. 5Ma is 0. 14MPa,and the peak relative pressure at 3Ma is 0. 018 MPa. The decrease of relative pressure is about 87% and the inlet condition is improved. After data comparison,the maximum mach number simulation deviation is 3. 9%,and the static pressure simulation deviation is 6. 5%.