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针对涡轮叶顶密封性能的提高,对圆形凹槽式迷宫密封的密封特性进行了研究。通过数值模拟一级半涡轮叶冠内及转子出口处的流场结构,分析了密封作用机理,密封间隙变化与泄漏损失以及掺混损失之间的关系。结果表明,圆形凹槽的容积效应促使泄漏流发生小角度偏转,降低了泄漏损失与掺混损失;密封间隙分别为0.3mm,0.5mm时,凹槽的存在改变了腔室内涡流涡核的位置;不存在凹槽时,间隙由0.3mm增大到2mm,泄漏系数增大53.3%;存在凹槽时,泄漏系数增大47.7%;间隙增大到1mm,掺混损失明显增大,凹槽密封掺混损失相对于光滑面密封掺混损失减少量保持在0.044左右。
Aiming at the improvement of turbine blade tip sealing performance, the sealing characteristics of circular groove labyrinth seal were studied. The relationship between the mechanism of sealing action, the change of sealing gap, the leakage loss and the mixing loss was analyzed by numerical simulation of the flow field structure inside the first-stage half-turbine blade crown and at the outlet of the rotor. The results show that the volume effect of the circular groove promotes the small angle deflection of the leakage flow and reduces the leakage loss and mixing loss. When the sealing gap is 0.3mm and 0.5mm respectively, the existence of the groove changes the eddy current vortex core in the chamber The gap increases from 0.3mm to 2mm, the leakage coefficient increases 53.3%; when the groove exists, the leakage coefficient increases 47.7%; the gap increases to 1mm, the blending loss increases obviously, the concave Slot seal blend loss is reduced to about 0.044 relative to smooth blend seal loss.