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This paper reports on the effects of transient transverse and axial acceleration forces with step changes in input power on the performance of a flexible copper/water arterial heat pipe. Transient transverse accelerations were generated using a centrifuge table to simulate acceleration forces typifying high performance aircraft maneuvering. These transients consisted of step changes, steady periodic, and burst cycles in the transverse acceleration forces. Steady periodic and burst cycle transverse accelerations had frequencies of 0.01 and 0.03 Hz with peak-to-peak values of 1.1 to 9.8 g. Partial depriming of the artery, pooling of the unconstrained working fluid, and fluid sloshing were found to have a significant impact on the heat transport potential and transient behavior of the heat pipe. Repriming of the heat pipe under thermal load while being subjected to transient transverse accelerations was also demonstrated.

This paper describes the potential of indirect liquid cooling to remove the waste heat generated while a MOS controlled thyristor (MCT) is operating at various power levels and switching frequencies. An MCT is mounted on a copper heat exchanger which is capable of removing up to 50 W of heat while maintaining the case temperature of the MCT below 50°C. At low switching frequencies, the MCT operates as expected at an applied voltage of 90 and 270 V. However, at 270 V, the device fails after a few minutes of continuous operation when the switching frequency is increased to 10 kHz.

The Air Force has sponsored a program at the University of Kentucky which will lead to a better understanding of the thermal and fluid instabilities during blowdown of supercritical fluids at cryogenic temperatures. An integral part of that program is the design and construction of a hydrogen test facility. This paper describes the design specifications and construction of that hydrogen test facility. This facility will be capable of providing supercritical hydrogen at 30 bars and 35 K at a maximum flow rate of 0.1 kg/s for 90 seconds. Also presented here is an extension of this facility to accommodate the use of supercritical helium.

Aircraft thermal management issues are reviewed in order to determine areas necessary for additional research. Particular topics discussed include the philosophy of traditional thermal control systems, the avionics cooling problem, and the application of heat pipes to aircraft systems. Avionics cooling includes a summary of current spacecraft cooling that is applicable. Analysis includes results for free convective cooling, forced convective cooling, and nucleate boiling heat transfer for low gravity applications as well as artificial gravity generation. Heat pipe applications are discussed with particular emphasis on the effects of high acceleration and nonuniform heat loads.