A Simple Evaporative System for Space-Environmental Thermal Control of Electronic Components

A passive mass transfer thermodynamic device employing the latent heat of vaporization of an enclosed liquid is described as a method of precise thermal control for single, low-mass, high-energy electronic components. This device has particular application for electronic components having high power density which are incorporated in spacecraft electronic systems relying otherwise on radiant exchange with the environment as a means of space-environmental thermal control. Specific areas of interest growing out of the design requirements for such a mass transfer device are 1) liquid ullage control under zero-g conditions, precluding loss of liquid due to blow-out, and 2) favorable exploitation of liquid adsorption and surface phenomena in maintaining a continuous heat-sinking effect. The latter effect is demonstrated by data obtained in operating appropriately instrumented thermal control test articles under one-g conditions in vacuum and non-vacuum environments. Satisfactory heat-sinking is demonstrated over a range of energy inputs. Application of the system methodology and capabilities to the problem of space-environmental thermal control is evaluated and summarized.