EXPERIMENTAL INVESTIGATION OF AIR-COOLED TURBINEnBLADES IN TURBOJET ENGINE XⅣ - ENDURANCE EVALUATION OF SHELL-SUPPORTED TURBINE ROTOR BLADES MADE OF TIMKEN 17-22A(S) STEEL

摘要

An investigation was conducted with a group of shell-supported, air-cooled turbine blades to determine (l) their durability in engine opera¬tion over a range of coolant-flow ratio (cooling-air to combustion-gas flow ratio) and (2) a design criterion for the type of air-cooled blades investigated herein. The blades investigated were nontwisted. They had formed shells of Timken 17-22A(S) steel (which contains approximately 96 percent iron) with mild-steel tubes inserted in the blade coolant pas¬sage to increase the coolant heat-transfer surface area. The blades were investigated in a modified J33 turbojet engine at rated engine conditions (engine speed of 11,500 rpm and calculated turbine-inlet temperature of approximately 1670 °F) and over a range of coolant-flow ratios from 0.015 to 0.042. At rated engine speed, the calculated average centrifugal stress is about 24,000 pounds per square inch at the 1/3-span region of the blade and about 32,000 pounds per square inch at the root of the blade.