Simulation of Throttling Response in Axial-Injection End-Burning Hybrid Rocket

Abstract

Axial-injection end-burning hybrid rocket (EBHR) is excellent in fuel regression rate and throttling characteristics than conventional hybrid rockets. However, in the firing tests of throttling operation using multiple port fuel, a very long response time was observed. In this research, the authors postulated that the fuel regression shape of each port might be affected by chamber pressure to explain the reason for long response time and verified this hypothesis by using numerical simulation. The calculation result showed the long response time, and the response time coincides with the shape-changing time, which indicates that the shape-changing causes a long response time. Moreover, the history of characteristic exhaust velocity suggests that the fuel-rich condition may make response time short.