An efficient and reliable design scheme for metal diaphragm propellant tanks

Metal diaphragm tanks utilize a metallic diaphragm to create a hermetically sealed partition within the tank, ensuring propellant storage and expulsion during flight missions. However, the design of metal diaphragm tanks involves high complexity, and the diaphragm is prone to wrinkling, eccentricity, or even rupture during inversion. To address this issue and meet mission-specific requirements (flight sequence, overload constraints, tank weight, pressure, and expulsion efficiency), this study proposes a highly efficient and reliable design scheme for a metal diaphragm tank. The tank adopts a spherical configuration, with an internal support ring and welded diaphragm structure for liquid management, while flange connections facilitate system integration. The tank shell and support ring are fabricated from titanium alloy (TC4), and the diaphragm is made of pure titanium (TA1ELI). Static simulation results demonstrate that both the tank shell and diaphragm remain intact under burst pressure conditions. Dynamic simulations reveal that the flange-augmented design significantly mitigates acceleration amplification near the diaphragm apex and fluid outlet, thereby enhancing the stability and reliability of the metal diaphragm during inversion.