An Investigation into the Mechanics of Joule-Thomson Valve Plug Formation

Numerical analysis of clogging dynamics in micromachined Joule–Thomson coolers

“…As shown in Fig. 4, the ice starts to form at the end of the high-pressure channel and the head of the restriction when the cold-end temperature reaches 170 K. As the cold-end temperature decreases the ice grows gradually against flow direction, which is similar to the observation of Wade et al (1988). The deposition rate increases with the increasing difference between the actual water pressure and the saturation water pressure as indicated by Eq.…”

“…Matching these electronics in size and cooling requirement, JT microcoolers provide cryogenic cooling power in the range of a few milliwatts to hundreds of milliwatts (Maytal and Pfotenhauer, 2013;Radebaugh, 2009). An important effect that limits the longterm performance of JT microcoolers is the deposition of impurities in the working fluid resulting in clogging of the microchannels (Lerou et al, 2007;Little, 1984;Maytal, 1998Maytal, , 2010Wade et al, 1988;Zhu et al, 2010). Wade et al (1988) observed the clogging formation in a straight glass JT expansion valve through a microscope and found that the ice formed initially near the low pressure side of the valve and then grew against the flow direction.…”

“…An important effect that limits the longterm performance of JT microcoolers is the deposition of impurities in the working fluid resulting in clogging of the microchannels (Lerou et al, 2007;Little, 1984;Maytal, 1998Maytal, , 2010Wade et al, 1988;Zhu et al, 2010). Wade et al (1988) observed the clogging formation in a straight glass JT expansion valve through a microscope and found that the ice formed initially near the low pressure side of the valve and then grew against the flow direction. Lerou et al (2007) imaged thedeposition of water molecules inside the cold end and the coldest part of the counter flow heat exchanger (CFHX) of a JT microcooler during operation.…”

Clog Retard of a Vortex Throttle Joule-Thomson Cryocooler: Further Experimental Verification

“…The variety of proposed clog retarding throttles includes, the vortex throttle [3], a labyrinth kind of a series of short throttles [4,5,6], a long capillary with a capability of heating up [7,8] and more [9]. Wade et al [10] experimentally studied the evolution of clog inside the expansion (cylindrical) orifice. Lerou et al observed that in their microelectromechanical systems (MEMS) cryocooler deposition of clog starts even before the throttle inside the narrow channels of the heat exchanger [11].…”