Research On The Flow In The Process Of The Propellant Management In A Spacecraft Tank Under Microgravity

Propellant management is significant in the design of the tank for the aircraft. Thiswork is on the background of the propellant management in the orbital refueling tank.It mostly focuses on the flow in the tank under microgravity. The thesis employs boththe analytic and experimental methods to study the basic flow theory with capillarity,the orientation process, the inflow process, and the exclusive of the propellant. It buildsa theory that can be used in the propellant management process, and provides multipletools for the design of the vane type refueling tank. Main work of the thesis are:(1) The fundamental governing equation for the free surface in a tank under micro-gravity and the theory of capillary rise. The Young-Laplace equation is explained withthe view of force balance. Meanwhile, the governing equation for the free surface in acylinder tank is solved; the theory of capillary rise is analyzed, and the equation is alsosolved. The theory is verified by the drop tower experimental data extracted from otherwork.(2)Theanalysisoftheorientationoftheliquidinthetank. Thegoverningequationisderivedfrom the flow continuity equation. A second order theoretical solution isobtainedby using the self-similar approximation method. Both the capillary experiments and thedrop tower experiments are used to verify the theory. The errors between the theory andthe experimental data are contributed to the change of the flow resistance in the flow.Furthermore, the theory is used to select the vanes in a tank to get a maximum flow ratewhile reducing the total mass.(3) The inflow stability during the refueling in the tank. The governing equation ofthe stable jet flow is derived by the pressure balance equation. Theoretical solution isused to analyze the influence of the jet parameters on the stability of the inflow. The ex-perimental data are analyzed by regression method. An approximated relation is obtainedbetween the geyser height and the filling height, Webber number as well as Bond number.This relation can be used for the tank design in applications.(4) The stability of the free surface during the exclusion of the propellant. The1-dimensional governing equation of the stability is derived from the Young-Laplace equa-tion combined with the momentum equation of the flow. Numerical method is used tosolve the equation to get the variation of the height of the free surface, the curvature, and the velocity along the flow path. Meanwhile,3-dimensional simulation of the forced flowin the channel is studied. The simulation finds that flow separation could occur after theflow pass though the lowest point of the free surface, which adds pressure loss to the flow.The drop tower experimental data are used to verify the theory as well as the simulation.(5) The experimental study of the forced flow in the channel. In the drop towerexperiments, the flow is classified as subcritical, supercritical, critical and super highspeed flow according to the development of the free surface. The flow type is identifiedby the convergence of the surface contour and the changing of the lowest point of thesurface; the experiments also found that the flow was influenced by both the oscillationof the flow and the flow development. Furthermore, the experiments also studied theimpact of the bubble injection on the flow. It showed that the bubble can stabilize theflow. The movement of the bubbles are influenced by the position of injection.This work develop a deep study on the flow of the propellant under microgravity byanalytic and experimental methods. It explores new areas of the study of the flow theoryand provides more methods for the study itself. This work could be used in the design ofthe refueling tank for the propellant management device.