Numerical method of flow and heat transfer characteristics of brush seals

Numerical methods for the flow and heat transfer characteristics of brush seals were studied，and the porous media，steady-state solid and transient fluid-solid-heat coupling models of brush seals were established respectively.An experimental device for leakage flow characteristics of brush seals was designed and built.On the basis of verifying the accuracy of the numerical method by experiment，the differences of three numerical methods were compared and analyzed，the flow and heat transfer characteristics of brush seals were studied.The sealing and heat transfer mechanism of brush seals was revealed.The research results showed that：under the working conditions，the error between the leakage calculated by brush seals porous media，steady-state solid and transient fluid-solid-heat coupling model and the experimental values was 9.8%-17.1%，8.1%-10%，6.92%-9.01%，respectively.The calculation speed of brush seals porous media model was faster，but experiment was required for correction of the porosity；the turbulence model had great influence on the flow and heat transfer characteristics of steady-state solid model；the transient fluid-solid-heat coupling model considered the interaction among flow，bristle and frictional heat，and the calculation accuracy was high，but the calculation time was longer.At the same pressure ratio，the temperature of bristle pack gradually increased from upstream to downstream，and the highest temperature of bristle pack increased with the increase of pressure ratio.The main reason for sealing of brush seals was attributable to the throttle effect of air flow through brush wire gap resulting in energy dissipation of leakage air flow，and the convective heat transfer between the leakage gas flow and the brush wire surface was the main form of friction heat dissipation of brush seals.