In order to study the automatic pressurization method for liquid attitude and divert rocket engines, based on the theoretical analysis of automatic pressurization system performance, the automatic pressurization experimental system was constructed based on orifice control elements, and the automatic pressurization performance experiments based on cold flow and a verified engine test were conducted with the human-simulated intelligent control strategy. The good smoothness, rapidity and accuracy were realized. The study shows that the system performance is determined by the orifice area, the orifice exit and entrance pressure ratio, and the propellant tank gas volume under the pressurization system structure and working medium. According to the test requirements of the engine flow rate, the parallel orifice group containing three inlet orifices of which the volume flow rates are equal to 60%, 30%, and 10% of the propellant volume flow rate respectively are organized. The maximum critical gas flow rate which is larger than the propellant volume flow rate (the recommended value is about 1~2.5) provided by the orifice group, the orifice exit and entrance pressure ratio which is approximately equal to gas critical pressure ratio (0.50~0.60 for nitrogen), the tank gas volume which is more than 1/4 of the tank are satisfied simultaneously, and the flow rate of outlet orifice is equal to 105% of maximum critical case, the automatic pressurization performance can be improved effectively based on automatic disposition of the orifices according to the human-simulated intelligent control strategy during the engine operation. © 2021 Editorial Department of Journal of Propulsion Technology. All right reserved.
