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The Two-Phase Fluid Loop (TPFL) System is a heat transport system for future large spacecraft, using latent heat of coolant. TOSHIBA Co. has developed a ground test facility capable of dissipating a 5kw heat load and tested the components of that facility since 1988. As a next phase, static characteristics of the TPFL system are being studied. In this paper, static behaviors under heat load variation are presented as results of the experimental study and the numerical simulation. For the experimental study, the above-mentioned ground test facility was used. In this facility, heat is finally dissipated to the heat exchanger using brine as a heat sink. In order to determine static behaviors for an actual radiator heat rejection system used in orbit, numerical simulation was carried out. To confirm the analytical model used in the numerical simulation, the numerical result and the experimental result were compared.

Toshiba, under contract to NASDA is studying two-phase fluid loops (TPFL) as a thermal management system for future space platforms. For these fluid loops, two types of volumetric pumps, a trochoid gear pump and a scroll pump, are being developed, because volumetric pumps are, among others, less sensitive to cavitation. Recently, we designed and fabricated a scroll pump for our 5kW heat rejection TPFL in order to achieve a continuous and quiet operation of the system, which is required for space use. This scroll pump has four scroll vanes, two fixed and two orbiting ones, to reduce pulsation of flow. This paper reports the performance test results of a bread board model (BBM). The trochoid gear pump completed up to the BBM level, is also designed under the same requirements for comparison. Component tests of the pumps are carried out prior to installation into the TPFL. As expected, the scroll pump showed weaker vibration and lower noise.

Since 1985 NASDA has made studies on advanced thermal management systems, especially on two-phase fluid loops, with a view to applying to temperature control and heat rejection of future space platforms of tens of kW class. Our research on pump-driven two-phase fluid loop technology is in a new stage where we have completed the design and fabrication of a development model. This paper describes the loop system design and gives details of components, which are three kinds of cold plates (grooved double-pipe type, grooved multi-channel type, tube and plate-heat-pipe type), two kinds of volumetric pumps (trochoid gear type, scroll type) and an accumulator of vapor pressure driven type. This paper, then, gives a brief description of an X-ray void meter which we have prepared for measurements of void fractions and for graphical observations of various flow patterns in the cold plates.