Dynamic and thermodynamic analysis of doubly motorized miniature Stirling cryocooler using double coil linear motors

• Published in: Cryogenics (Guildford) 1994, Vol.34 (1), p.43-50
• Main Authors: Gaunekar, A.S, Narayankhedkar, K.G, Bapat, S.L
• Format: Article
• Language: English
• Subjects: Applied sciences; Cryogenics; dynamic analysis; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Refrigerating engineering. Cryogenics. Food conservation; Stirling cycle cryocoolers; thermodynamics
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/0011-2275(94)90051-5

Small capacity Stirling cryocoolers (∼ 1 W at 80 K) for space-borne applications generally use linear electromagnetic drives (also called linear motors) for long, maintenance-free life and high reliability. Usually, such motors employ a single moving coil. Recent trends, however, favour a double coil configuration for higher motor efficiency. Earlier, in free piston, free displacer (FPFD) Stirling cryocoolers the displacer was driven by the pressure pulses from the compressor. The latest units have a split configuration, with the displacer also being driven by a small capacity linear motor, giving better control over its mean position, stroke and phase lead over the compressor piston. After establishing a mathematical model for the working of a double coil linear motor, this paper analyses the link between thermodynamic performance and the dynamics of the two reciprocating components in a doubly motorized FPFD Stirling cryocooler, thus presenting a design tool for such cryocoolers.