液氧煤油发动机汽蚀故障主动控制策略仿真研究

Simulation of active control strategy for cavitation failure of LOX/kerosene engine

以氧化剂预压泵入口压力作为监测对象,在氧化剂主泵汽蚀故障时通过动作流量调节器减少进入预燃室的燃料流量,进而稳定混合比、抑制燃气温升,达到避免过高燃气温度造成灾难性后果的目的。设置燃料路流量调控为98.8%、97.2%、89.5%和74.5%的额定流量和0、0.15、0.23 s和0.30 s四种调控延时的控制策略,通过仿真研究其有效性。结果表明:汽蚀故障下燃料最佳节流量是保持混合比为额定值的取值;最大允许时间延时随着汽蚀故障严重程度的增加而降低。当贮箱压力在0.10 s内降低至额定压力的53%、43%和33%时,最大允许动作延时分别为0.23、0.17 s和0.13 s;最佳控制时间延时参考值为0.09 s,增大延时导致部分组件参数出现超调,减小延时会存在发动机熄火的风险。

Taking the inlet pressure of the oxidizer boost pump as the monitoring object,the fuel flow rate into the gas generator can be reduced by the action flow regulator during the cavitation failure of the oxidizer main pump,then the mixture ratio can be stabilized and the combustion temperature can be suppressed,so as to avoid the catastrophic consequences of excessive gas temperature.The control strategies of 98.8%,97.2%,89.5% and 74.5% rated flow rate and the control delay of 0,0.15,0.23 s and 0.30 s were set up.The effectiveness was studied by simulation.The results showed that the optimum fuel flow rate under cavitation failure was used to keep the mixing ratio rating,and the maximum allowable time delay decreased with the increase of cavitation failure severity.When the tank pressure was reduced to 53%,43% and 33% of the rated pressure within 0.10 s,the maximum allowable action delay was 0.23,0.17 s and 0.13 s,respectively.The optimal control time delay reference was 0.09 s,increasing the delay led to overshoot of some component parameters,and reducing the delay led to the possibility of engine flameout.