HEAT PIPE COOLING OF TURBOSHAFT ENGINES

THE PROPOSED WORK PLAN WILL EXAMINE THE USE OF HEAT PIPE COOLING IN TURBOSHAFT ENGINES TO INCREASE PERFORMANCE BY REDUCING OR ELIMINATING THE COMPRESSOR DISCHARGE BLEED AIR REQUIRED TO COOL ENGINE COMPONENTS. AREAS TO BE EXAMINED INCLUDE VANES, SHROUD, AND THE INTER-TURBINE DUCT. FOR TURBOSHAFT ENGINES, ENGINE CYCLE ANALYSIS PREDICTS THAT THE USE OF HEAT PIPES WILL INCREASE NET SHAFT HORSEPOWER WHILE DECREASING FUEL CONSUMPTION. FOR EXAMPLE, USING HEAT PIPES TO COOL THE HIGH AND LOW PRESSURE TURBINE STATORS COULD INCREASE SHAFT HORSEPOWER BY 8 PERCENT, WHILE DECREASING FUEL CONSUMPTION BY 3.8 PERCENT. IN ADDITION, SINCE THE HEAT PIPES WILL REPLACE THE CURRENT COOLING PASSAGES, PROBLEMS DUE TO BLOCKAGE OF COOLING PASSAGES BY SAND AND DUST WILL BE ELIMINATED. IN PHASE I OF THE PROGRAM, ENGINE COMPONENTS THAT CAN BENEFIT FROM THIS INNOVATIVE HEAT PIPE COOLING METHOD WILL BE IDENTIFIED AND EVALUATED. INFORMATION ON THERMAL BOUNDARY CONDITIONS AND PHYSICAL SIZE CONSTRAINTS WILL BE SUPPLIED BY THE SUBCONTRACTOR, GARRETT ENGINE DIVISION (GED). IN PHASE II, HARDWARE WILL BE FABRICATED TO TEST THE MOST PROMISING COOLING CONCEPTS. COMPONENTS WILL BE TESTED AT GED IN A RIG TEST DESIGNED TO SIMULATE THE APPROPRIATE ENGINE ENVIRONMENT.