斯特林机动力活塞间隙密封动态特性仿真分析  

Simulation of Dynamic Characteristics of Clearance Seal of Power Piston of Stirling Machine

作　　者：宫晶 张君安[1] 王亚娟 卢志伟[1] 刘波[1] GONG Jing;ZHANG Jun’an;WANG Yajuan;LU Zhiwei;LIU Bo(School of Mechatronic Engineering,Xi’an Technological University,Xi’an Shaanxi 710021,China;College of Coal and Chemical Industry,Shaanxi Energy Institute,Xi’an Shaanxi 712000,China)

机构地区：[1]西安工业大学机电工程学院,陕西西安710021 [2]陕西能源职业技术学院煤炭与化工产业学院,陕西咸阳712000

出　　处：《润滑与密封》2022年第10期104-111,共8页Lubrication Engineering

基　　金：陕西省自然科学基金项目(2020JM-720);陕西省教育厅科研计划项目(20JC016);陕西省自然科学基金项目(2021JM-428);陕西省创新能力支撑计划项目(2020KJXX-016)。

摘　　要：在自由活塞斯特林机动力活塞间隙密封中,间隙内的气体泄漏会引起工作腔内压力和气体质量的变化,进而影响斯特林机的工作效率。为研究在压缩循环过程中气体泄漏量对压力的动态影响,建立间隙密封长度不变、间隙密封长度单侧变化和间隙密封长度双侧变化3种不同的间隙密封物理模型,采用时间推进法,分析求解不同形式的密封对泄漏量的影响。结果表明:间隙密封在启动阶段时单向泄漏量最大,随着时间的推进,泄漏量逐渐减小后达到稳定,间隙密封长度不变的模型相较于其他2种模型的单向泄漏量最少。基于间隙密封长度不变的模型,分析气膜厚度、背压、密封长度对泄漏量的影响,对气膜间隙和背压进行优化设计。结果表明:气体质量的泄漏随气膜厚度和背压的增加而增加,随活塞长度的增加而减小;当气膜间隙为20~30μm,活塞长度为10~15cm,背压在3~5 MPa时,间隙密封泄漏量在3%以内,符合动力活塞间隙密封的设计要求。分析结果为自由活塞斯特林机动力活塞间隙密封提供了设计依据。In the clearance seal of free piston Stirling power piston, the gas leakage in the clearance will cause the change of pressure and gas quality in the working chamber, and then affect the working efficiency of Stirling machine.In order to study the dynamic influence of gas leakage on pressure during the compression cycle, three physical models of the clearance seals, the model with clearance seal length unchanged, the model with unilateral change of clearance seal length and the model with bilateral change of clearance seal length were established, and the time advance method was used to analyze and solve the influence of different types of seals on the leakage.The results show that the one-way leakage of the clearance seal is the largest at the start-up stage.With the time advance, the leakage gradually decreases and then reaches stability.The one-way leakage of the model with clearance seal length unchanged is the least compared with the other two models.Based on the model with clearance seal length unchanged, the influence of film thickness, back pressure and seal length on the leakage was analyzed, and the design of film gap and back pressure were optimized.It is found that the leakage of gas mass increases with the increase of gas film thickness and back pressure, and decreases with the increase of piston length.When the gas film gap is between 20 μm and 30 μm, the piston length is from 10 cm to 15 cm and the back pressure is from 3 MPa to 5 MPa, the leakage of the clearance seal is controlled within 3%,which is in line with the design of the power piston clearance seal.The analysis results provide a reasonable design basis for the free piston Stirling machine power piston clearance seal.

关 键 词：间隙密封 动态特性 斯特林机 动力活塞 密封长度 

分 类 号：TB651[一般工业技术—制冷工程]