流场不均匀对液体火箭发动机纵向振荡燃烧影响及控制

The vortex instability and pressure oscillation in the flow field are one of the important reasons for the high frequency longitudinal combustion instability of liquid rocket engine. Considering the regenerative cooling channel and impinging jet injectors in the thrust chamber ofnormal temperature propellant rocket engine，the flow field of the connecting part between the thrust chamber body and the injector was analyzed， and its uniformity were measured experimentally. Results showed that the circumferential non-uniform pressure at outlet of regenerative cooling channel was about 0.15 MPa. The use of throttling at the outlet of the cylindrical section of the thrust chamber can significantly increase the local fluid velocity and the turbulence and non-uniformity of the oxidant at the injector，thereby changing the combustion characteristics. The atomization test of impact injection unit was carried out，and the propellant inlet boundary velocity of 18 m/s was obtained. Based on the flow field uniformity of the injector，a control method of suppressing the longitudinal high frequency combustion instability was proposedby controlling the propellant flow rate and reducing the non-uniformity. The engine thermal test results showed that the control method suppressed the longitudinal high frequency combustion instability of the thrust chamber at the propellant inlet flow rate of (15±1) m/s.