自由活塞斯特林机动子运动阻尼特性研究

RESEARCH ON DAMPING CHARACTERISTICS OF MOVERS IN FREE PISTON STIRLING ENGINES

为准确描述自由活塞斯特林机动子的动力学特性,将黏性阻尼与库伦阻尼的分离计算法引入动子的运动阻尼分析中。通过理论分析和实验验证,并与等效黏性阻尼计算法进行对比,证明了分离计算法的正确性和实用性。研究结果表明:动子在往复运动中的接触摩擦与常规接触摩擦不同,其阻尼力既不只是一个定常摩擦力,也不只是速度的线性函数,而是由于往复运动,动子的局部接触情况随位移发生变化,表现为与位置相关的摩擦力。因此,动子往复运动中的阻尼特性应采用一个黏性阻尼系数与一个定常摩擦力共同描述。

A separate calculation method of viscous damping and Coulomb damping was introduced into the kinematic damping analysis to accurately describe the dynamic characteristics of movers in free piston Stirling engines.Based on theoretical analysis and experimental verification,and compared with the equivalent viscous damping calculation method,the correctness and practicability of the separate calculation method were verified.The results show that the contact friction of movers in reciprocating motion is different from the conventional contact friction.Its damping force is neither only a constant friction nor only a linear function of the velocity,but a position dependent friction as the local contact of the mover changes with the displacement due to reciprocating motion.Therefore,the damping characteristics of the reciprocating movers should be described by the combination of a viscous damping coefficient and a constant friction.