基于 TDLAS 技术的喉栓式变推力发动机羽流速度特性

To investigate the plume velocity characteristics，a numerical simulation model of plume of the pintle controlled solid rocket motor considering afterburning reaction is established，using the finite-rate reaction model and dynamic mesh. The model is combined with Tunable Diode Laser Absorption Spectroscopy（TDLAS）technology to calculate the plume velocity. The transient flow field during the pintle motion is analyzed，and the effects of after-burning reactions and measurement position on velocity measurement investigated. The results show that the transient plume field changes periodically with the reciprocal motion of the pintle. When the pintle tends to close the nozzle，a strong shock wave appears near the nozzle. The downstream plume velocity distribution is more uniform，indicating the reduced influence of the velocity gradient on TDLAS measurement；the afterburning reaction leads to significant changes in the downstream velocity and H₂O component distribution of the plume. Along the downstream direction，the influence of afterburning on the oscillation amplitude of the velocity along the TDLAS optical path gradually increases. In practice，to reduce the influence of afterburning and the velocity gradient，the measuring position should be closer to the nozzle to obtain measurement closer to the axis velocity.