On the aerothermodynamic study of the SSME HPOTP ball bearing inside a vapor film

In order to predict ball bearing temperature in the Space Shuttle Main Engine (SSME) high-pressure oxidizer turbopump (HPOTP), knowledge of ball bearing heat transfer coefficients is important. To understand the heat transfer behavior of a ball bearing operating under a two-phase environment, a flow simulation model of a rotating sphere inside a vapor film has been developed to determine the effects of rotational speed and vapor film thickness on ball heat transfer. The calculated Nusselt number is compared with experimental data for a rotating ball in liquid nitrogen.