Design and preliminary experiment of a 0.3 × 0.15 m2 low-disturbance supersonic wind tunnel

To meet the requirement for the low disturbance of wind tunnel flow in supersonic boundary layer transition simulation tests, a low-disturbance supersonic research wind tunnel with a nozzle size of 0.3 × 0.15 m2 and test Mach number of 3.0 was built. It was then used to study key design technologies for increasing the size and Reynolds number of low-disturbance supersonic wind tunnel. The wind tunnel adopted a “blowdown + ejection” layout to achieve a wide pressure range of 50–450 kPa. A “sintered wire mesh + honeycomb + damping mesh” structure was adopted in the settling chamber with the flow straightening method to achieve velocity pulsations of less than 0.3% and pressure pulsations of less than 0.1% at the exit. A comprehensive design technique for the supersonic laminar nozzle was adopted, which included nozzle boundary layer suction and highly polished surface nozzle processing. At a total pressure of 450 kPa, a low-disturbance supersonic test area with an axial length of about 9 cm was realized. The airflow pressure pulsations in this area were less than 0.15%, and the Reynolds number based on the characteristic length reached 1.3 × 106.