Analytical Approach and Computer Model Development for Performance Investigations of Liquid Droplet Radiators

The liquid droplet radiation (LDR) affords lighter weight for high-power (>100 kilowatt) spacecraft by eliminating the solid radiating surface. This is accomplished by shooting a droplet sheet of radiator fluid from an ejector to a collector thus allowing the fluid to radiate directly to space. The volumetric nature of the radiative transfer introduces added complexity in the thermal analysis of the LDR. Key performance information for LDR designs, such as interior droplet sheet temperature distribution and local heat flux, cannot be determined by assigning an effective emissivity and absorptivity to the sheet.

An analysis and computer model has been developed which realistically models the nature of the radiative exchange by determining volumetric interchange factors using ray tracing and a Monte Carlo technique. The computer analysis returns sheet temperature distribution and heat rejection information for a rectangular-shaped droplet sheet with specified optical depth and ejector and collector temperatures.