低前挡板型小尺寸刷式封严泄漏特性的试验

Experimental investigation on leakage characteristics of small size brush seal with low front plate

对间隙、过渡、过盈3种配合状态的低前挡板型小尺寸刷式封严的转子轴心轨迹和泄漏特性进行了实验研究.转子的轴心位移采用电涡流传感器进行测量,其测量结果表明:压差小于0.4MPa时,转子轴心位移随压差的增大略有减小;当压差达到0.4MPa后,其轴心位移范围不再随压差而变化;在不考虑磨损的情况下轴心位移对不同配合状态的封严泄漏特性基本没有影响.由此确保了封严试验台的安全性和有效性.在此基础上,试验研究了转子转速、上下游压差以及封严间隙对泄漏特性的影响.结果表明:泄漏系数随转速增加略有减小;间隙配合下有明显的滞后,过盈配合下滞后不明显;磨损对泄漏的影响在过盈配合下比较显著;间隙配合下压差在0.1~0.2MPa泄漏系数随压差的升高而增大,压差为0.3MPa时泄漏系数降低,0.3MPa以后泄漏系数变化趋于稳定;过盈配合下泄漏系数随压差的升高总体呈增大趋势,压差在0.3~0.5MPa时增大的趋势较小,泄漏系数较为稳定.

Experimental research on rotor＇s axis locus and leakage characteristics of brush seal with low front plate at clearance/transition/interference fit states was carried out. The rotor＇s axis locus was measured by using eddy current sensor. The results showed that： rotor＇s axis locus became smaller with increase of differential pressure when the differential pressure was less than 0.4 MPa. Rotor＇s axis locus didn＇t vary with differential pressure when the differential pressure exceeded 0.4MPa. Rotor＇s axis locus didn＇t affect the leakage characteristics of brush seals for different fit states if wear was not taken into account. This could ensure the safety and effectiveness of the experiment rig. Based on this, the effects of rotational speed, differential pressure and sealing clearance on leakage characteristics were studied. The result shows that. leakage coefficients increase with the increment of the rota- tional speed. Brush seals have obvious hysteresis under clearance fit and inconspicuous hys- teresis under interference fit. The effect of wear on leakage characteristics is obvious at in- terference fit state. Leakage coefficients of brush seal increase with the increment of differ- ential pressure ranging from 0.1 to 0.2 MPa under clearance fit, and decrease when the dif- ferential pressure is 0.3 MPa, and tend to be stable when the differential pressure exceeds 0.3 MPa. Leakage coefficients of brush seal show an increasing trend with the increment of differential pressure under clearance fit, and the increasing trend slows down and leakage co efficients enter into a stable state when the differential pressure ranges from 0.3 to 0.5 MPa.