Design and performance study of side water inlet device of underwater vehicle engine

Metal water fuel engines possess advantages such as high energy and specific impulse, simple structure, and safe and pollution-free fuel, making them suitable for underwater supercavitating vehicles. Due to the combustion chamber's internal working pressure of about 3 MPa, under the speed conditions of 40-70 m/s, the external seawater total pressure is lower than the engine's internal pressure, preventing the liquid flow from entering the engine and causing the engine to malfunction. To address this issue, this paper proposes a lateral water intake pressurization system configuration, completes the parametric design of the lateral water inlet flow channel and the pressurization pump design, and predicts the feasibility of the design results through CFD numerical simulation. The numerical simulation results of the pressurization system indicate that the total head of the device has a relative deviation of less than 5% compared to the design value, and the system can increase the incoming flow total pressure by about 4.9 MPa, and the outlet total pressure reaches 5.6 MPa, enabling the stable operation of the metal water fuel ramjet engine at a speed of 50 m/s. The research findings have reference value for the performance study of lateral water intake pressurization pump devices in water ramjet engines.