The subscale nozzle model of a liquid rocket engine was researched.The corresponding flow field configurations were analyzed.The influence of main parameters of the secondary jet injector on control effectiveness was analyzed

including the injection angle

the area ratio and the total temperature of its working fluid.The results indicate that

when the secondary jet injector is adopted

the nozzle inlet total pressure which can make the nozzle reach full flow decreases 37.8%;as the injection angle increases from 0° to 25°

the nozzle flow separation location moves about 0.01m towards the nozzle throat

and the control effectiveness of the device decreases significantly;as the total temperature of the injector's working fluid increases from 300K to 1500K

the nozzle flow separation location moves about 0.005m towards the nozzle exit

and the control effectiveness of the device increases slightly. The area ratio has no effect on flow separation location when no flow separation occurs in the secondary jet injector

otherwise

the control effectiveness of the device will decrease.