Abstract: Realizable k-ε turbulence model, dynamic mesh update method and finite-rate/dissipation model are used to establish an initial cavity secondary combustion flow model with missile movement for research on the influence of combustion product properties on gas-ejection secondary combustion, interior ballistic and load characteristics. The effectiveness of gas ejection model is proven by comparing the calculated data with the experimental data. The influences of combustion product pressure in gas generator inlet and component concentration on gas-ejection interior ballistic and load characteristics are analyzed. The variation ranges of inlet pressure and concentration ratio are obtained. The numerical results show that, with the increase in inlet pressure，the times of O₂ exhaustion and the time out of tube decrease, and the velocity out of tube and the acceleration peak value increase. With the increase in the concentration ratio of CO and H₂, the time of O₂ exhaustion increases, the time out of tube is extended, and the velocity out of tube and the acceleration peak value decrease.

Key words: ordnance science and technology, combustion product property, secondary combustion, gas-ejection, dynamic mesh, interior ballistic