The influence of water vapor on the internal flow characteristics within a hydrogen circulation pump

Abstract

This study examines the effects of water vapor on the performance and stability of a Roots-type hydrogen circulation pump. The accuracy of the numerical model was initially confirmed using air as the experimental medium, and subsequent simulations were conducted with pure hydrogen or mixed media containing water vapor. Analysis of pressure and velocity distribution within the pump revealed that water vapor does not significantly impact these factors. However, the interaction between hydrogen and water vapor results in the formation of larger hydrogen clusters, reducing internal leakage flow and leading to a slight increase in inlet and outlet flow rates. The presence of water vapor in the suction chamber increases turbulence energy in the root region of the rotor, influencing flow patterns and creating multi-scale vortex structures. In the exhaust chamber, the turbulence energy is lower and there are fewer vortices, but high-energy vortices may occur at the connection to the exhaust pipe, affecting the outlet flow rate.