Safety design of the piston rod seal structure for submerged high-pressure liquid hydrogen pump

Abstract For the submerged high-pressure liquid hydrogen pump, a core piece of equipment of liquid hydrogen transportation, extensive analysis, and research were conducted on its components and structure during the development process. By referencing typical failure probabilities in the energy industry and statistical data from prototype pump development and testing, a list of failure probabilities for each part of the liquid hydrogen pump was compiled, and the consequences of those failures were deduced. The nitrogen liquid test experiment verified the possibility of pump seal failure and identified the fault modes. It confirmed that the piston rod seal is one of the critical components prone to failure in the liquid hydrogen pump. Subsequently, six important technical optimization measures for the piston rod seal pair have been carried out, reducing the probability of failure. Moreover, based on the concept of inherent safety, the sealing structure of the piston rod was innovatively designed, transforming hidden failures into visible ones, facilitating timely detection and monitoring of failures, and greatly reducing the safety risks caused by piston rod seal failure. The improved liquid hydrogen pump successfully passed subsequent tests, ensuring its long-term safe operation.