Heat Separation in Frictional Rotor-Seal Contact

Abstract

The development of thermal bows in rotors is frequently reported. The cause of the bows is an asymmetric temperature distribution as a result of uneven heating. The heat source can be a friction contact between rotor and seal. Both partial and full annular rub can give asymmetric heating. A general model for these two cases is a rotor with an arbitrary elliptic orbit and an eccentric position in an elliptic seal. Depending of these kinematics, different regions of the rotor and seal are heated and the heat flow resistance effected. Closed-form solutions of the heat conduction in three spatial dimensions are well known for the point source and after integration this is suited for friction heat analysis. When the temperature distribution is expressed the thermal bow follows as a volume integral. This paper focuses on the relation between rotor vibration (via friction heating in the seals) and the thermal bow. The coupling from rotor bow back to vibrations is treated in a later work. The main contribution of this paper is a semi-analytical solution of the thermal bow dynamic function.