Experimental research on separation diaphragm performance in propellant storage and feed systems of liquid propellant tanks

This paper presents the results of comprehensive research on the operational performance of diaphragm separators utilized in the fuel storage and supply systems for liquid-propellant rocket engines (LPRE). The relevance of this study arises from the need to ensure the reliable separation of gas and liquid duringthe operation of aerospace systems under diff erent conditions. In this context, special attention is given to autonomous bench tests that enable the evaluation of the key performance parameters of diaphragms before integrating them into production models. The paper examines the shape transformation of spherical diaphragms under external loads, presents an analytical calculation of the initial diaphragm inversion radius, and identifi es the critical pressures that cause buckling. The results of this calculation demonstrate a satisfactory correlation with the experimental data obtained during testing. The methodology for qualifi cation tests conducted on fi ve diff erent diaphragm variants is described. Several technological and design measures have been implemented to enhance product quality. They included increasing the number of drawing passes from two to three with intermediate annealing, reducing the thickness of the blanks, and enlarging the non-rolled polar zone. It was found that the primary factor ensuring defect-free diaphragm inversion is the reduced number of roller passings along the diaphragm contour, which prevents the tearing of the surface layer. The test results for diff erent diaphragm variants confi rmed satisfactory performance. An analysis of pressure diff erentials across the diaphragms during inversion confi rmed compliance with the technical specifi cations. The study concluded that the diaphragm design, when it incorporates all corrective measures, ensures defect-free inversion while maintaining the required pressure diff erential and is recommended for further testing as part of standard tank assemblies.