Liquid Level Control Using a Porous Plug in a Two-Phase He II System
This paper presents results of an experiment which decouples the liquid counterflow component from the evaporative component of heat transfer in the two-phase He II system. Two baths, partially filled with He II, are connected by a vapor tube at the top and a liquid tube at the bottom. Temperature and liquid level differences between the two baths are measured as a function of heat input into one bath while temperature of the other bath is held constant. A copper porous plug with 30,576 parallel channels of length 1.29 cm and diameter 30 μm is inserted in the bottom tube, which partially restricts flow of the normal fluid component. The liquid level height difference between the two baths is governed by the thermomechanical effect and saturated pressure differences. A numerical model of the combined modes of heat transport is able to predict temperature and liquid level differences accurately. A properly sized porous plug will not restrict heat flow and can reduce the undesirable liquid level differences between components at different temperatures.
KeywordsLiquid Level Saturated Pressure Porous Plug OFHC Copper Bottom Tube
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