关键词: 单组元推力器, 硝酸羟胺, 催化点火, 气动谐振加热, 低温起动

Abstract: In order to achieve the rapid catalytic ignition startup of hydroxylammonium nitrate (HAN)-based monopropellant thruster under low temperature, a novel preheating technique called gas dynamic resonance heating is proposed and employed to efficiently heat the front section of the catalyst bed. Using nitrogen as the resonance working fluid, three starts under low temperature (?9 °C)were conducted on a 20N HAN-based monopropellant thruster equipped with a gas dynamic resonance heater, meanwhile the heat transfer process inside the combustion chamber of the internally heated monopropellant thruster was studied through simu-lation calculations. The test results show that using nitrogen as the resonant working medium, the HAN-based thruster can achieve rapid catalytic ignition and startup under low-temperature conditions, reducing the preheating time required for tradi-tional catalytic bed electric heating from tens of minutes to tens of seconds, significantly shortening the ignition delay time. The preheating time for low-temperature pre-pulse ignition was reduced to approximately 20 seconds. The heat transfer calculation shows that the resonance heater can stably output a heating power of about 30-35 W; During the pre-pulse ignition phase, the pressure rise gradient is large, and the thermal accumulation effect causes a rapid temperature increase inside the combustion chamber. At the end of this phase, the temperature difference between the casing and the interior of the catalyst bed is about 500°C. In the formal pulse operation phase, the catalyst bed has already reached a relatively high temperature level. The casing temperature is about 200°C lower than the temperature inside the catalyst bed. During the continuous operation phase, due to the continuous supply of propellant, the maximum temperature inside the catalyst bed reaches around 1150°C and the temperature difference from the casing is about 600°C. The research has shown that the application of the gas dynamic resonance heating technology can achieve the rapid catalytic ignition startup of HAN-based monopropellant thruster under low temperature.

Key words: Monopropellant thruster, Hydroxylammonium Nitrate, Catalytic ignition, Gas resonance heating, Ignition under low temperature