Extended Gas Generator Cycle for Re-Ignitable Cryogenic Rocket Propulsion Systems

Kurzfassung

Liquid rocket propulsion systems are able to provide thrust at high specific impulse. Especially for upper stage propulsion systems this high efficiency is strongly wanted. A high ratio of thrust to weight is obtained by rocket engines based on the gas generator cycle. Another wanted characteristic of an upper stage engine is the ability of re-ignition. An extended gas generator cycle is presented in this paper which includes the ability of several re-ignitions of the propulsion system. The main components of this extension are two high pressure bottles for the gas generator supply only during start up transient. Due to the self-pressurisation effect the modules can restart the gas generator several times during flight. The switch over from the high pressure bottles to the pump supply during transient is investigated in this study by means of the software package EcoSimPro. This study was performed as a Diploma-Thesis in the frame of the project Turbomachines in Rocket Engines (TIR) supported by the Institute of Space Propulsion, DLR-Lampoldshausen. The simulation proves the feasibility of the extended gas generator cycle and indicates in which applications it has significant advantages.