ADVANCED COLDPLATES FOR LINE REPLACEABLE MODULES

ADVANCED AVIONICS COOLING FOR LRM/IAR OBJECTIVE: DEVELOP A MORE EFFICIENT COLDPLATE FOR APPLICATION TO THE LINE REPLACEABLE MODULES TO REDUCE THE OPERATING JUNCTION TEMPERATURES, AND IN ADDITION, DEVELOP AN LRM COMPATIBLE INTEGRATED AVIONICS RACK (IAR) WITH A DISTRIBUTED COOLING SYSTEM FOR IMPROVED LRM RELIABILITY IN RETROFIT APPLICATIONS. DESCRIPTION: THE AVIONICS FUNCTIONAL CHIPS WITHIN THE LRM'S ARE MORE SENSITIVE TO HIGH OPERATING TEMPERATURES THAN OLDER ELECTRONICS AND REQUIRE MORE COOLING PER CUBIC INCH OF FUNCTIONAL CIRCUITS. MATERIALS AND MATERIALS COMBINATIONS ARE AVAILABLE TO OPTIMIZE THE LRM COLDPLATE. PRESENT MATERIALS, SUCH AS ALUMINUM ALLOY, ARE PROVIDING ADEQUATE STIFNESS BUT AT THE EXPENSE OF THE WEIGHT, THERMAL CONDUCTIVITY AND THERMAL COEFFICIENT OF EXPANSION (CTE) . A NEW "TAILORED" MATERIAL COMBINATION CAN IMPROVE ON ALL OF THESE CHARACTERISTICS AND CAN BE APPLIED TO THE LRM AT A REASONABLE COST. THE MAIN GOALS, HOWEVER, ARE THE LOWERING OF THE JUNCTION OPERATING TEMPERATURES AND THE MATCHING OF THE CTE TO CIRCUIT BOARD ASSEMBLIES. ADEQUATE RELIABILITY OF THE VHSIC TYPE LRM'S WILL REQUIRE BOTH A REDUCED THERMAL RESISTANCE WITHIN THE LRM AND A LOWER RACK COLDWALL TEMPERATURE THAN CAN BE PROVIDED BY EXISTING AIRCRAFT ECS'S . IT MAY BE FEASIBLE TO DEVELOP A MINIATURE FREON COMPRESSOR/CONDENSER SYSTEM THAT CAN BE BUILT INTO A RETROFIT IAR THAT WILL PROVIDE THE LOWER OPERATING TEMPERATURES AND THAT WILL ONLY REQUIRE ADDITIONAL ENGINE DRIVEN ELECTRICAL POWER.