EXPERIMENTAL INVESTIGATION OF A CONTINUOUSLY CONTROLLED PRESSURIZATION SYSTEM FOR REUSABLE LAUNCH VEHICLES

At present, solenoid valves are widely used in the pressurization system of launch vehicles to regulate pressurization gas flow. Since the solenoid valve has only two states, it needs to be switched on and off constantly to maintain the tank pressure near the target value during the working process of propulsion system. However, wastage of sealing surface limits the reuse of the solenoid valves. It is necessary to design a new throttling device to increase the number of times of use and realize continuous and stable pressurization for reusable vehicles. In this paper, an adjustable Venturi tube is proposed to replace the solenoid valves in the pressurization system. The non-linear error in the relationship between the pintle axial displacement and the flow rate is eliminated through the special profile of the pintle. Theoretically, the profile can maintain a good linear correspondence in the regulating process, thus improving the regulating accuracy. The structural design and manufacturing of the adjustable Venturi tube device were completed in the research. A pressure control system was also developed. A test pressurization system based on the adjustable Venturi tube was built and primary tests were carried out. According to the test results, for an unsteady upstream pressure around 1MPa, the system controls the target tank pressure accurately corresponding to 0.3MPa, 0.35Mpa, 0.4MPa, 0.45MPa and 0.5MPa respectively, with accuracy requirement of ± 0.02MPa. It also shows that the system can achieve precise and stable pressure regulation within required accuracy range during simulated engine throttling operations.