Structural Study on Moving Magnet Compressor for Stirling Engine
The article describes a structural study on moving magnet compressor for Stirling engine. The performance of Stirling engine is determined by the linear compressor. The article first establishes mathematics models for ordinary linear compressors and moving magnet compressors manufactured for test and analysis, then studies magnetic field distribution of linear moving magnet compressor by CAE, the results show that magnet analysis has an agreement with the measurements. A modified moving magnet compressor prototype is proposed based on the results.
A study on the linear compressor characteristics of the Stirling cryocooler
Abstract The purpose of this study is to analyze the characteristics of the linear compressor for Stirling cryocooler. To ensure high performance and long life of the free piston, free displacer Stirling cryocooler, the operating parameters of the linear compressor should be optimized. The experimental results show the operating frequency of the linear compressor has significant effect to the input power characteristics, and the compressor with higher charging pressure of working fluid has high pressure ratio. For the high performance of the linear compressor, compressor has uniform magnetic force with different stroke, and the optimal operating frequency with respect to the charging pressure.
Nonlinear Dynamics of an Oilless Linear Drive Reciprocating Compressor
Two modeling methodologies of the dynamics of a motor-compressor system are presented. The first approach considered only the mechanical system subjected to a sinusoidal input force with the pressure term in the equation of motion treated as a nonlinear stiffness term. The second methodology consisted of a mathematical model that couples the electromagnetic and thermodynamic equations to the dynamic equations that describe the motion of the piston. The mathematical model which consisted of a set of four first order simultaneous nonlinear time varying differential equations was solved by numerical integration routines that use the Adams-Moulton method with an adaptive integration step. The two methodologies are illustrated through an example. Steady-state operation was shown to be reached rapidly after a 0.13s transient. An analysis at various amplitudes and frequencies of the input voltage in the driver-coil of the motor showed the amplitude dependence of the natural frequency of the mechanical system, and a heavily damped system when operating at the design amplitude. The most efficient frequency of operation was also determined for a variety of required mass flow rates.