LIQUID FILM EVAPORATION COOLED MIRROR

EVAPORATING A COOLANT FROM THE SURFACES OF A FINE POROUS WICK CAN DO SOMETHING NO OTHER KNOWN COOLING SCHEME CAN DO: MAINTAIN A NEARLY CONSTANT SURFACE TEMPERATURE WHILE THE HEAT FLUX IS VARIED BY TEN TIMES OR MORE. THE PROGRAM GOAL IS TO COOL HIGH-POWERED LASER MIRRORS, AND OTHER TOUGH COOLING PROBLEMS. THE UNIQUE HEAT EXCHANGER DESIGN IS AN ADVANCED COUSIN OF THE HEAT PIPE AND OF PUMPED TWO-PHASE (BOILING) COOLING DESIGNS DEVELOPED BY THERMACORE. LIQUID FILM EVAPORATION (LFE) COOLING WORKS BY MAINTAINING A STABLE EVAPORATING LIQUID FILM LAYER OVER THE WICK SURFACES. AS THE HEAT FLUX GOES UP, THE FILM THICKNESS GOES DOWN, SO THE SURFACE TEMPERATURE CHANGES ARE MINIMIZED. ABSORBED HEAT FLUXES UP TO 500 W/CM2 CAN BE REMOVED BY LFE. FUNDAMENTALS ARE BEING STUDIED IN PHASE I; PHASE II WILL REDUCE THE APPROACH TO PRACTICE WITH ACTUAL LFE COOLED MIRRORS.