Based on the principle of air turbo rocket

the condition

equation and line of co-work and its influence factors were presented. According to the co-working equation

the influence law of area of the throat for nozzle and total temperature of gas at the inlet of turbine on the co-working line was given. The result showed that the mass flow rate of air for the engine increased and the pressure ratio of compressor decreased as the numerical value of area of the throat for nozzle or total temperature of gas at the inlet of turbine increased on the same rotational velocity line

which made the co-working line move toward lower right direction. The influence law of area of the throat for nozzle and total temperature of gas at the inlet of turbine on the co-working line was similar

but the influence effect of area of the throat for nozzle was more obvious.