Cryocooler Resonance Characterization

Abstract An important issue in the design and scaling-up of Stirling cryocoolers is achieving good drive motor efficiency and launch survivability. The important common thread linking these two topics is the dynamic resonant response of the compressor and displacer moving masses. The fundamental equations governing cryocooler mechanical efficiency and launch vibration response are presented and explored in terms of their implications for cooler design. The resonant frequency, damping and drive motor force parameters associated with the cooler are shown to be key to efficient operation. Means of measuring these parameters are presented and shown to have broad applicability to additional parameters such as drive stiction and vibration transmitted to the instrument. The resonant parameters of the BAe 55 K AIRS proof-of-concept cooler are used as an example to demonstrate the good correlation between the analytical fundamentals and the measured characteristics of a state-of-the-art cryocooler design.