The effect of viscous dissipation and heat transfer on friction losses of grease-filled labyrinth seals

Abstract

This paper puts forward a numerical investigation of non-isothermal grease flow in labyrinth seals. The effects of heat transfer and viscous thermal dissipation in mechanical losses were evaluated. An Arrhenius-type equation was employed to represent the dependence of grease viscosity on temperature and included in the mathematical modeling. The heat transfer and the viscous dissipation, which is magnified by the shaft rotational speed, increase the flow temperature that reduces grease viscosity and consequently, friction losses. The influence of the labyrinth materials (steel and polymer) on the heat lost and therefore, on the viscous losses, was also assessed. Polymer labyrinths provided higher temperature levels in comparison to steel labyrinths because of the its lower thermal conductivity.