Flowrate controller for hybrid capillary/mechanical two-phase thermal loops

摘要

A hybrid capillary/mechanical two-phase thermal loop has a sensor connected in parallel with a number of evaporators to regulate the flowrate of a booster pump providing working fluid to the evaporator capillaries. This sensor is made of a coiled, conductive tube connected in parallel with the evaporators, with an inside diameter substantially greater than the inside diameters of the evaporator capillaries. A conductive wire extends within said tube, but is insulated from electrical contact with the tube. The working fluid contained within the tube acts as a dielectric between the tube and wire. The amount of liquid phase working fluid within the tube can be determined by measuring the electrical capacitance between the tube and wire. The flowrate of the booster pump is then regulated as a function of the measured capacitance to maintain a substantially constant amount of liquid phase working fluid within the sensor tube. The sensor thereby effectively regulates the flowrate of working fluid from the pump to match the aggregate demand of the evaporators.