Study on bias residual control of high mixture ratio bi-propellant

Lift capacity is the key performance of the launch vehicle, and high chemical energy bi-propellants are commonly used for the modern large liquid rockets. The residual unburned propellant has a strong effect on the lift capacity and the lift efficiency, especially for the orbital stages. In this paper, the bias residual control of high mixture ratio propellant is studied, three models, including equal-probability depletion model (EPDM), equal-mass residual model(EMRM) and optimum residual model(ORM) are analyzed. Comparing with the traditional equal-probability depletion, the bias residual control of bi-propellants, especially for LOX and LH2, is benefit to the lift capacity. The effect between EMRM and ORM on the residual unburned propellant is negligible, and the EMRM is preferred in engineering.