减压腔宽度对刷式密封泄漏特性和滞后效应的影响

Influence of axial wide of pressure relief chamber on leakage characteristics and hysteresis of brush seals

对减压腔轴向宽度分别为0、0.4 mm和0.6 mm的基本型和两种低滞后刷式密封结构进行了静态和动态下压差升降和转子转速升降循环试验,并对其泄漏特性和滞后效应进行了研究。研究结果表明:压差大于0.2 MPa后,同一压差下的动态泄漏系数比静态降低约14%~20%;低滞后结构的密封性能优于基本型,其泄漏系数最高比基本型降低约20%;静态压差升降循环中,减压腔轴向宽度为0.6 mm的低滞后结构的滞后效应最强;动态的压差升降循环中,基本型结构的滞后效应最强。转子转速升降循环前后,w为0.6 mm结构泄漏系数减小约15%,滞后效应最强,减压腔轴向宽度为0.4 mm结构几乎不存在滞后效应;三种结构中,减压腔轴向宽度为0.4 mm的结构密封性能最优,滞后效应也最弱。

The leakage characteristics and hysteresis effect of different axial width of pressure relief chamber of 0,0.4 mm and 0.6 mm with the conventional and low hysteresis brush seals were studied under the static and dynamic tests of pressure difference rise and drop and the rotor speed rise and drop.The results showed that:the dynamic leakage coefficient was about 14%-20%lower than the static one,when the pressure drop was more than 0.2 MPa.The sealing performance of low hysteresis brush seals was better,and the leakage coefficient was up to about 20%lower than the conventional brush seal.The hysteresis effect was the strongest in the process of pressure difference rise and drop cycle with the static condition when axial width of pressure relief chamber was 0.6 mm.The hysteresis effect of conventional brush seal was the strongest in the process of pressure difference rise and drop cycle with the dynamic condition.After the rotor speed rise and drop cycle,the leakage coefficient decrease by about 15%when the axial width of pressure relief chamber was 0.6 mm,and there was basically no hysteresis effect when the axial width was 0.4 mm.In addition,for the three structures,the brush seal with the axial width 0.4 mm had the best sealing performance and the weakest hysteresis effect.