Abstract
The figure of merit of a pulse tube is the ratio of total power to pV power flowing up and out of the hot end of the pulse tube. The figure of merit is less than unity because of heat transport from the hot end to the cold end. Streaming-driven convection in the pulse tube can contribute to this heat transport.
In a well instrumented pulse tube refrigerator having 1500 W of cooling power at 125 K, we have measured the figure of merit of a tapered pulse tube at several operating points. At operating points near those for which the taper should eliminate streaming-driven convection, the figure of merit is 0.96 ± 0.04. This is close to the theoretical optimum figure of merit 0.97 calculated for this pulse tube considering only two heat-transport mechanisms: heat conduction in the metal pulse tube wall and ordinary boundary-layer thermoacoustic heat transport in the gas close to the wall. At other operating points, the measured figure of merit is much lower, as streaming-driven convection adds a third heat-transport mechanism.
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© 2002 Kluwer Academic Publishers
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Swift, G.W., Allen, M.S., Wollan, J.J. (2002). Performance of a Tapered Pulse Tube. In: Ross, R.G. (eds) Cryocoolers 10. Springer, Boston, MA. https://doi.org/10.1007/0-306-47090-X_37
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DOI: https://doi.org/10.1007/0-306-47090-X_37
Publisher Name: Springer, Boston, MA
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