空化对低温浮动环密封流场和密封特性的影响  

Effects of Cavitation on Flow Characteristics and Sealing Properties of Cryogenic Floating Ring Seals

作　　者：张奇 叶小强[1] ZHANG Qi;YE Xiaoqiang(Beijing Aerospace Propulsion Institute,Beijing 100076,China)

机构地区：[1]北京航天动力研究所,北京100076

出　　处：《润滑与密封》2022年第3期138-149,共12页Lubrication Engineering

摘　　要：为探究典型工况下单相和两相空化流动的流场及密封特性,对考虑过渡段的低温浮动环密封进行数值仿真,对比分析转子面、密封间隙轴向及周向的压力分布特点,并探究单相和两相流动条件下进口压力、进口温度、转子偏心率以及转子转速对泄漏量、进口损失系数、密封力和偏位角的影响。研究结果表明:同心状态下,单相流和两相流的流场均具有对称性;偏心状态下,单相流在大间隙内的介质压力要低于小间隙,而两相流在密封段出口附近呈现出相反规律,致使大间隙附近的空化程度更低;随进口压力和偏心率的增加以及转速的降低,泄漏量和密封力均增加,且两相流特性值均低于单相流对应值;两相流泄漏量和密封力均随进口温度的降低而增加,而单相流对应值受温度变化的影响不大;单相流偏位角受各个参数变化的影响均很小,密封力方向始终在最小间隙附近位置,而两相流偏位角的波动性则相对较大,且随进口温度的升高而加剧;单相流进口损失系数随进口压力升高、偏心率减小以及转速升高而略有增加,而两相流进口损失系数随各个参数的变化更为敏感。In order to study the flow characteristics and sealing properties of single phase and two-phase cavitation flows under typical working conditions,the numerical simulation of cryogenic floating ring seals with transitions was carried out,and the features of pressure distribution of rotor face,axial and circumferential direction in the seal clearance were compared and analyzed.The effects of inlet pressure,inlet temperature,eccentricity and speed of rotor on leakage rate,flow loss coefficient,seal force and angle of displacement under single phase and two-phase flow conditions were investigated.The results show that under concentric state,the flow fields of single phase flow and two-phase flow are symmetrical.Under eccentric state,the pressure at larger clearances is lower than that at smaller ones in single phase flow,but greater in the vicinity of seal exit when two-phase is applied,resulting in a lower extent of cavitation near the larger clearance.The leakage rate and seal force both increase as rotor speed decreases or inlet pressure and eccentricity increase,and the characteristic values of two-phase flow are lower than those of single phase flow.The leakage rate and seal force both increase as inlet temperature drops in two-phase flow,while the corresponding values of single phase flow are not affected by the change of temperature.The angle of displacement of single phase flow is little affected by the changes of various parameters,indicating the direction of seal force is always in close proximity to the position of minimum clearance.While the fluctuation of the angle of displacement of two-phase flow is relatively large,and it intends to intensify with the increase of inlet temperature.The inlet flow loss coefficient of single phase flow increases slightly as eccentricity decreases or inlet pressure and rotor speed increase,while the inlet flow loss coefficient of two-phase flow is more sensitive to the changes of various parameters.

关 键 词：空化 浮动环密封 典型工况 流场特性 密封特性 

分 类 号：TB42[一般工业技术]