Micro-Scale Nozzle Technology Used in a Compact Thermal Management System for Solid-State Lasers

Solid-state lasers (SSL's) are the most likely near term lasers that can be considered for deployment on space-based platforms. These electric laser systems pose unique challenges in that the cooling system must dissipate heat loads that are often ten times greater than the laser output, with high heat fluxes over large surface areas and limited heat rejection. Existing water-based micro-channel cooling technology requires large coolant flow rates and high pressure heads, leading to heavy and bulky thermal management systems that are not suited for deployment in space, and existing space qualified heat pipe cooling technologies are not capable of handling the heat fluxes of 100-350 W/cm2 generated by the laser diodes. In this effort Rini Technologies, Inc. proposes an innovative evaporative spray cooling (ESC) technique that will reduce the mass and volume of SSL cooling systems in space. The ESC system utilizes unique micro-nozzle arrays can dissipate the high heat fluxes generated by the laser diodes with substantially lower coolant flow rates and reduced pressure drops compared to micro-channel cooling techniques. If shown to be feasible, the proposed micro-nozzle ESC system can provide high heat flux thermal control to space based SSL's with acceptable weight impacts to the spacecraft increasing the laser power-to-mass and laser power-to-volume ratios.