The effects of air-cooling the turbine rotor blades on the per-formance of an axial-flow turbojet engine were calculated for a range of altitude from sea level to 40,000 feet. The measured wind-tunnel performance of a commercial turbojet engine was used as the basis, of comparison with the calculated performance for a turbine inlet tempera-ture of 1960° R and for a range of cooling-air flows up to 3 percent of the compressor air flow. A flight Mach number of 0.788 was assumed for all altitudes.nThe percentage change in thrust and specific fuel consumption com¬pared with the performance of the uncooled engine is plotted for two cases:(l) with the cooling air bled from the compressor at the pres¬sure required for each coolant flow;(2) for cooling air bled at the compressor discharge and throttled to the pressure required for each coolant flow for the entire range of conditions.
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