迷宫刷式密封泄漏特性的实验和数值研究

Experimental and Numerical Investigations on the Leakage Flow Characteristics of Labyrinth Brush Seals

具有优良封严性能和对转子的瞬时偏心涡动适应性很强的刷式密封在透平机械间隙流动控制中得到应用。论文实验和数值研究了迷宫密封和两种刷丝束与转子间隙c(0.7 mm、0.8 mm)的单级迷宫刷式密封在转速0~3000 r/min和压比1.1~2范围的泄漏特性。研究表明:迷宫刷式密封的封严性能优于迷宫密封,泄漏量随压比和密封间隙c的增大而增大;迷宫刷式密封泄漏迟滞效应随转子转速升高而减弱。刷丝束的上下表面的径向压差和上下游面的轴向压差随压比的增大和密封间隙c的减小而增大,进而刷丝束闭合效应和轴向弯曲程度增大.论文工作为迷宫刷式密封设计和泄漏特性分析提供参考。

Due to excellent sealing performance and strong adaptability to rotor excursions,brush seals are widely used in turbomachinery to control the leakage flow through rotor-stator clearances.The present paper experimentally and numerically investigated the leakage flow characteristics of a labyrinth seal and two types of single-stage labyrinth brush seals at the rotational speed of 0~3000 r/min and the pressure ratio of 1.1~2.The single-stage labyrinth brush seal has a radial clearance(c)of 0.7 mm or 0.8 mm between the bristle pack and the rotor.The results show that the sealing performance of labyrinth brush seals is superior to that of the labyrinth seal.Leakage flow rates of seals increase with the increase of the pressure ratio and the radial clearance(c).Leakage hysteresis effect of the labyrinth brush seal decreases with the increasing rotational speed.The radial pressure difference between the upper and lower surfaces of the bristle pack and the axial pressure difference between the upstream and downstream surfaces increase due to the increase of the pressure ratio and the decrease of the radial clearance(c),and thus the blow down effect and the degree of axial bending of the bristle pack increase.This work provides a reference for the design and leakage characteristics analysis of labyrinth brush seals.