The dissertation objective is to extend the current theoretical understanding of loop heat pipe performance relative to potential ground vehicle applications. Little knowledge exists about LHP performance under body forces, temperature extremes (-40°C to 40°C) and diurnal/seasonal fluctuations anticipated with ground vehicle environments. Several unique investigations occurred during this research. LHP performance was characterized as a function of a 4m hydrostatic pressure head, variable and periodic spin table tests, condenser performance and liquid line return temperature.; The testing for this research occurred at the Thermal Engineering Branch, NASA-Goddard Space Flight Center and combined to produce hundreds of individual test scenarios. Five distinct series of experiments were performed involving three different loop heat pipes systems. The five distinct tests are placed in three separate categories: Acceleration, Pressure Drop, and Thermal Effects. Acceleration testing evaluated the effects of gravity and spin table induced effects on LHP startup behavior, low power and high power operation, and power cycling tests. A vapor side metering valve increased pressure drop to evaluate impact on loop operating temperature. Thermal effects included evaluations of condenser performance and sizing along with liquid line return temperature. Liquid line return temperature was shown to be one of the most important variables with respect to the loop operating temperature, particularly at moderate to high operating temperatures.
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