Numerical simulation for the satellite hydrazine propulsion sysyem

Numerical simulations have been conducted to investigate the effects of various key design parameters on the transport behavior of the propellant flow for a hydrazine-based satellite propulsion system. The flow-channel network numerical scheme was used to determine the blowdown curves for characterizing the propulsive performance of typical 500 kg-class small satellites at different tank sizes and thrust values. This work covers the tank volume from 91 1 to 104 1 and the thrust force from 1 N to 8.896 N. In order to explore the response of transient propagating waves, a theoretical model in conjunction with the method of characteristics (MOC) was solved numerically to obtain the pressure and propellant mass flowrate histories under various simulated conditions. These conditions consider different thrust levels, the layout with or without an orifice installed, different total pipeline lengths, and altered duration setting of thruster-valve opening/closing periods in a 250- ms attitude control cycle. The predicted results indicate that the installation of an orifice can rapidly damp out the fluid-hammer induced pressure oscillations compared with the case without an in-line orifice. For different total pipeline lengths, the Fourier spectrum analysis reveals that a longer pipeline shows a lower first-mode frequency with a higher spectral intensity in trend. To probe an optimum opening time of thruster valve for the pulse-mode operation, it is found that the setting of 80-ms opening/170-ms closing time intervals may maintain a relatively stable propellant mass flowrate during the pulse trains for rendering a reasonable impulse performance.