TABLE OF CONTENTS The Joule-Thomson (JT) effect is the cooling of a fluid that occurs when the fluid expands, moving from high pressure to low pressure under constant enthalpy conditions. (Although "JT effect" can also refer to the heating of a fluid, this discussion only addresses fluid expansion that produces cooling and refrigeration effects.) The basic closed-cycle apparatus (Fig. 10.1) is quite straightforward. High-pressure fluid leaves a compressor and flows through a recuperative heat exchanger. Cooling of the fluid is then produced by expansion to a lower pressure through the JT valve. The fluid flows to an isothermal heat exchanger, where the load is applied. Then, after again passing through the recuperative heat exchanger, the fluid returns to the compressor, where it is pumped back to high pressure, and the cycle repeats. Open-cycle JT coolers, in which the working fluid is vented to space after expansion, are discussed in Chapter 4.
Because of several advantages they provide over other coolers, JT coolers are enticing for some flight applications.
Cooling can be supplied at relatively large distances (many meters) from the compressor, reducing vibration and electromagnetic interference (EMI) at the cold tip.
The flow path allows flexibility in packaging and integration.
Cooling can be distributed over large areas.
Generation of saturated...
