Cooling behaviors of a novel flow channel in mechanical seals of extreme high-speed rotation for cryogenic rockets

Abstract

Mechanical seals usually require a special cooling system to control the high temperature generated by friction heating of rotating rings under the condition of extreme high-speed rotation. The working fluid is often in direct contact with the friction surface, and there is a risk of leakage. In the present paper, a novel cooling scheme driven by centrifugal force is proposed to cool the mating face in mechanical seals of turbopump in cryogenic rockets, which could achieve the absolute zero leakage of cooling fluid. To verify the flow feasibility and cooling effect of the new cooling structure, a three-dimensional numerical model is developed to predict the high-speed rotational flow and fluid–solid coupled heat transfer for liquid oxygen. The results show that the novel cooling scheme to cool the rotating ring II in the mechanical seal of cryogenic engines is reasonable and feasible, which could run itself relying on the radial centrifugal force, and could effectively control the temperature of the rotating ring II within the allowable range of the materials. This paper provides a new idea for cooling structure of mechanical seals in cryogenic rockets and numerical experience for ultra-high speed rotating flow and heat transfer with phase change.