Design and Simulation of Fuel Injectorof a 10N Monopropellant Hydrazine Thruster

Monopropellant thruster of atitude control system is a requirement for the development and functionalization of satellites in space, which have expensive and high-tech technology. Hydrazine thrusters are currently the most widely used thrusters for guidance and control systems of re-entry and manned spacecraft. In this paper, design and computation of an injector with hollow-cone spray with two tangential inlets as a fuel injector of a 10N monopropellant hydrazine thruster is presented. This injector has designed based on Bazarov method so that can generate a spray with a common (not so big) spray angle and very thin liquid sheet. Therefore it will be suitable from aspect of limitation of the catalyst bed length and also gives finer atomization. The phenomenon of creating and developing an air core in the internal flow of these injectors and its simulation is complex due to the existence of two turbulent swirl flows in two different phases, liquid and gas, which have an interface. For this injector, simulation of the internal flow has been performed to predict the output flow characteristics and ensure the formation of the gas core inside it. These characteristics include the spray cone angle, liquid sheet thickness, the output velocity distribution of the injector nozzle, and etc. For this purpose, volume of fluid (VOF) method has been used and flow turbulence has been simulated using the k-e model. The results of this study is presented in detail in the paper.