Study on calibration of effective test time in high enthalpy shock tunnel

In order to accurately obtain the effective experimental time of the high-enthalpy flow field in the shock wind tunnel driven by high-pressure hydrogen, the high-frequency pressure sensor technology, high-frequency thermocouple technology and high-frequency TDLAS water component measurement technology were used to calibrate the high enthalpy operation process and the effective test time of the test flow field in the shock tunnel with 50 MPa hydrogen driving 0.1 MPa air, combined with CFD numerical simulation. The results show that the high-pressure hydrogen gas in the driving section and the air in the driven section would burn in the contact area, causing a significant increase in temperature in the local area of the shock tube. The water produced by the combustion would diffuse into the air in the low-pressure section, causing pollution to the test gas and shortening the effective test time of the shock tunnel. The high-frequency heat flux measurement technology and the water component measurement technology based on TDLAS can effectively identify the arrival time of the hydrogen/air contact surface and realize the quantitative measurement of the effective test time of the high-enthalpy flow field in the shock tunnel. The effective test time of the Mach number 10 flow field in the Φ2 m shock tunnel A of the Hypervelocity Aerodynamics Institute under the above operating conditions is 2.6 milliseconds.