Structural design of a large flow pressure compensation valve based on flow force compensation and optimization

Spacecraft rely on umbilical arms to supply gas, deliver power, and load fuel. Moments before liftoff, these arms must swiftly and smoothly retract, a process managed by flow control valves equipped with pressure compensating valves (PCVs). For heavy-lift rockets, the umbilical arms require significantly greater driving power, necessitating stable pressure compensation by the PCVs under large flow conditions, particularly at a rated flow of 800 L/min. However, under such conditions, the spool of the PCV is subjected to significant, highly nonlinear flow force, making it difficult to achieve proper alignment with the spring stiffness. This mismatch severely impacts the pressure regulation performance of the PCV. To enhance the alignment between the flow force curve and spring stiffness under large flow conditions, finite element simulations were initially conducted on the designed hollow-spool PCV. These simulations provided mapping data between the valve port structural parameters and flow force, which served as the basis for constructing response surface models for the linearity and magnitude of the flow force curve. Subsequently, a multi-objective flow force optimization algorithm based on NSGA-II was designed. After clustering analysis of the optimized structures, the linearity of the flow force curve improved by 43.6 %. To further reduce the magnitude of the flow force and enhance spool stability, two flow force compensation structures were designed based on the optimized geometry. The maximum flow forces were reduced to 494 N and 530 N, representing decreases of 29.7 % and 24.6 %, respectively. Finally, a large flow force testing platform was designed to evaluate the flow force curves of the two schemes under various operating conditions. The results demonstrated a maximum deviation of 10.6 % between simulation and experiment, and the measured pressure differential across the throttling port remained stable at 0.7 MPa and a flow rate fluctuation within 6.6 %, confirming the effectiveness of the proposed compensation design. This study provides a research method for correcting flow force curves and has significant implications for improving the stability of large flow control valves.