Ignition theory investigation and experimental research on hybrid rocket motor

A transient ignition model is established based on the theoretical analysis of hybrid rocket motor ignition process. The ignition process can be divided into four stages: inert heating, ignition, flame propagation, and rapid pressure buildup. The inert heating up time takes up the main part of the ignition delay. An experiment system is designed for 90% hydrogen peroxide laboratory-scale hybrid rocket motor with catalytic ignition. Firing tests are carried out with polymethyl methacrylate (PMMA) and polyethylene (PE) fuels. The ignition criteria of 90% H2O2/PE hybrid rocket motor are established by comparing the theoretical calculations with experimental results. Comparison results show that the ignition process is governed by both the temperature criterion (TC) and the oxidizer-to-fuel ratio criterion (OFC). OFC determines ignition delay at a low oxidizer mass flux and TC determines ignition delay at a higher mass flux. In addition, the ignition delay time is more sensitive to the initial oxidizer temperature than the initial fuel temperature.