线性压缩机中间隙密封泄漏的微观机理研究
Research on Microscale Mechanism of Clearance Seal Leakage in Linear Compressor

线性压缩机内部的活塞与气缸内壁面之间存在间隙，而间隙的厚度对压缩机运行效率影响甚大。间隙过小会导致磨损的可能，减少压缩机使用寿命；间隙过大又起不到密封工作流体的作用，造成相当一部分损失。基于分子动力学方法，建立了线性压缩机的物理模型，研究了线性压缩机在做正弦交变运动时，活塞运行频率、活塞行程、间隙宽度及间隙长度对间隙密封泄漏的影响关系。研究发现：泄漏量随频率和行程的增大而减小，且两者都使压缩机压比增大。在气缸总尺寸不变时，活塞宽度减小即间隙宽度增加时，泄漏量增大，压比以平方关系下降；活塞长度增加时即间隙密封长度增大，但是泄漏量和压缩机压比几乎没有变化。研究表明间隙宽度及活塞行程对泄漏量影响较大。
There is a gap between the piston inside the linear compressor and the inner wall of the cylinder, and the thickness of the gap has a great influence on the operating efficiency of the compressor. If the gap is too small, it will lead to the possibility of wear and reduce the service life of the compressor; if the gap is too large, it will not be able to seal the working fluid, causing a considerable part of the loss. Based on the molecular dynamics method, the physical model of the linear compressor is established, and the influence of the piston operating frequency, piston stroke, gap width and gap length on the leakage of the gap seal is studied when the linear compressor performs sinusoidal alternating motion. It is found that the leakage decreases with the increase of frequency and stroke, and both increase the compressor pressure ratio. When the total size of the cylinder remains the same, when the width of the piston decreases, that is, when the width of the gap increases, the leakage increases, and the pressure ratio decreases in a square relationship; when the length of the piston increases, the length of the gap seal increases, but the leakage and the compressor pressure ratio are almost the same. The research shows that the gap width and piston stroke have a great influence on the leakage.