New Preliminary Design Method of Pump-Fed System in a Cryogenic LPRE Base on Gradient and Genetic Algorithms

In this paper, a new method for preliminary design of feed system (FS) in a cryogenic liquid propellant rocket engine (LPRE) has been developed. The cycle type of LPRE is pump-fed system and staged combustion. Engine cycle consists of main turbopump with reactive gas turbine, a fuel booster pump with hydro turbine and an oxidizer booster pump with active gas turbine. This method based on four specifications, proper cavitation number in pumps especially in oxidizer component, power balance between pumps and turbines, strength of material in main rotor of turbopump and mass evaluation of FS determine the type of FS components and calculate initial requirements for preliminary design of each of them. Calculation shows that employing of booster pumps improve the cavitation characteristic of main pumps and consequently decrease FS mass, but causes added mass to fed-system. Optimum point could be achieved through using genetic algorithm, in which all involving parameters could be considered. Results of the method compared with the same engine scheme. Comparison of the results confirms the correctness of the method and enhancement of FS characteristic parameters.