Numerical Investigations on Influence Factors of Leakage Flow and Heat Transfer Characteristics of Brush Seal

As a kind of contact sealing technology, the frictional heat generation between bristles and rotor is becoming a major concern for the seal performance and operation life of brush seals. The mathematical model of leakage flow and heat transfer of brush seal analysis with consideration of frictional heat generation between the bristle pack and rotor is established to offer a reference for the design of high performance brush seal. Reynolds-Averaged Navier-Stokes (RANS) based on the Non-Darcian porous medium model and local thermal non-equilibrium energy equation coupled with finite element method is conducted to analyze the leakage flow and heat transfer performance of brush seal. Effects of pressure ratios, rotational speeds and the hence heights of backing plate on the leakage flow and heat transfer characteristics of brush seal are numerically investigated using presented numerical method. The obtained results show that the leakage flow rate of brush seal slightly decreases with increase of the rotational speed without considering the frictional heat generation effect. The leakage flow rate of brush seal significantly decrease with the rotational speed increases with consideration of the frictional heat generation effect. The leakage rate of brush seal at 8kr/min is reduced to 69% of no-rotational case considering the frictional heat generation between the bristle pack and rotor. The highest temperature of the bristle pack increases with the increasing of the pressure ratio, the rotational speed and the fence height. The decrease rate of bristle pack temperature along the radial direction increases with the increasing of the pressure ratio and the fence height. The interference between rotor and bristle pack increases with consideration of the rotor centrifugal growth effect at high rotational speed case. This behavior results in the variation of the frictional heat generation effect of brush seal. © 2018, Editorial Department of Journal of Propulsion Technology. All right reserved.