Conjugate Heat Transfer Analysis of Oil-Mist Cooling and Lubrication System of Bearing Supports for Small Gas Turbine Engine

One of the trends of improvement of a small-sized gas turbine engine design is increasing the reliability of high-revving rotor bearing supports. This can be accomplished by using the alternative cooling and lubrication system, such as oil-mist system. This article presents the results of a conjugate heat transfer CFD analysis of the oil-mist cooling and lubrication system for the rotor bearing supports of a gas generator in a small-sized gas turbine engine. The specific features of an oil-mist cooling system, which ensures optimal temperature parameters and reliable bearing operation at high rotational speeds, are examined. A developed mathematical model comprises thermodynamic and gas-dynamic processes occurring in the system, including the influence of air and gas flows on the rotor's thermal state. In order to evaluate hydraulic characteristics of the system and thermal condition of the critical rotor parts, the analysis is conducted for various flow parameters. The findings refine the strength calculations of the rotor and are useful for optimization of the cooling system's design, which has practical value for improving the reliability and durability of gas turbine engines.