双缸型直线压缩机非线性动力学特性分析

Nonlinear Dynamics Characteristics of Dual-cylinder Opposed Compressor Driven by Linear Motor

为获得双气缸式直线压缩机工作过程中的活塞运动特性,耦合压缩机气体作用力方程和直线电机推力方程,建立了工作过程活塞非线性动力学模型。运用能量平衡原理对非线性振动方程进行了求解,获得了动力学模型的近似解析解,分析了活塞运动的稳定性特点和工作过程幅频关系。研究结果发现:双缸型直线压缩机工作过程具有明显的自激振动特点,初始时刻压缩机运动状况不影响最终的运行结果,经过一定时间后,活塞运动会趋于稳定的极限环,最终达到恒频恒幅运动;活塞运动频率不具有"固定频率"属性,它不仅受到压缩机物理结构参数的限制,同时也受到电机推力和进气压力的影响;随着进气压力的增加,活塞运动频率增大,且在高负荷状态下,压缩机活塞运动频率主要受进气压力决定。

A nonlinear dynamics model of the compressor is established based on thermodynamics equations and the electromagnetic force equation,in order to study the dynamics characteristics of the piston in a free-piston compressor driven by a linear motor.The approximate solution of the nonlinear model is solved by the energy equilibrium method based on the oscillation theory.The stability and frequency characteristics of the piston in the linear compressor are discussed in terms of the solution of the nonlinear model.The results show that the movement principle of the linear compressor is a single degree vibration system with self-excited force.The initial movement does not affect the final operation of the compressor,and the piston motion tends to be stable.Piston motion frequency is influenced by the compressor′s physical structure,the linear motor thrust and the intake pressure.The electromagnetism force determines the piston′s movement amplitude and has a serious impact on the piston′s vibration frequency.The piston motion frequency increases with intake pressure,and is mainly decided by the inlet pressure under larger load conditions.