A steady-state numerical approach for the thermo-structural analysis of a cryogenic piston pump

Abstract

Abstract The process of liquefaction of gaseous fuels, such as natural gas or hydrogen, is an essential technology that helps reduce transportation costs over long distances. Cryogenic piston pumps play a critical role in these systems, as they compress the fuel up to 700 bar before vaporization and storage in high-pressure vessels. Due to the extreme temperatures and pressures involved, the design of these machines poses a significant challenge from the thermal and structural point of view. This work presents the application of a simplified numerical approach for evaluating the thermally induced stresses and deformations through a de-coupled thermo-structural three-dimensional analysis of a prototype cryogenic piston pump. Thermal simulations of the solid domain are carried out to assess the steady-state temperature distribution of the pump. The heat transfer between the pump and cryogenic liquid is computed using three-dimensional steady-state CFD simulations of the suction and discharge phases. Heat generated by friction during the working cycle of the pump and external natural convection are calculated and imposed as a heat source in the simulations. The steady-state temperature distribution is imposed in a finite-element steady-state three-dimensional structural simulation to evaluate the combined effect of thermal loads induced by the cryogenic temperatures and loads induced by the high working pressures. Results show how the proposed methodology can assist in the design of cryogenic piston pumps by offering valuable insights into the most critical aspects of these machines.