INVESTIGATIONS OF AIR-COOLED TURBINE ROTORS FOR TURBOJET ENGINESⅠ - EXPERIMENTAL DISK TEMPERATURE DISTRIBUTION IN MODIFIED J33 SPLIT-DISK ROTOR AT SPEEDS UP TO 6000 RPM

摘要

An experimental investigation is being conducted at the Lewis laboratory to establish general principles for the design of noncritical turbine rotor configurations. This investigation includes evalu¬ation of cooling effectiveness, structural stability, cooling-air flow distribution characteristics, and methods of supplying cooling air to the turbine rotor blades.nPrior to design of a noncritical rotor, a standard turbine rotor of a commerical turbojet engine was split in the plane of rotation arc machined to provide a passage for distributing cooling air to the base of each blade. The rotor was fitted with nontwisted, hollow, air-cooled blades containing nine tubes in the coolant passage.nIn the investigation reported herein, the modified turbine rotor operated .successfully up to speeds of 6000 rpm with ratios of cooling-air to combustion-gas flow as low as 0.02. The disk temperatures observed at these conditions were below 450° F when cooling air at 100° F was used from the laboratory air system. The calculated disk temperatures based on the correlation method presented for rated engine conditions were well below 1000° F at a cooling-air flow ratio of 0.02, which is considered adequate for a noncritical rotor. An appreciable" difference in temperature level existed between the forward and rear disks. This temperature difference probably introduced undesirable disk stress distributions as a result of the relative elongations of the two disks. This investigation was terminated at 6000 rpm so that slight changes in the engine configuration could be made to relieve this condition.