The demand for increased performance in turbojet engines has necessitated an increase in the operating temperatures of various engine components. To this end, metallurgical engineers have made significant improvements in the properties of high-strength metals. The metallurgical state-of-the-art, however, is not sufficient to satisfy the requirements of the propulsion engineer. The air-cooled turbine, therefore, has been developed. The higher operating temperature levels require a more critical study of temperature distribution and of the resultant operating stresses in the blading. The utilization of the analogy between heat flow and electrical flow is described herein as the basis for a method of determining the chordwise-temperature distribution and heat-transfer rates in the air-cooled turbine blades. A general review of the mathematical derivation of analog theory is included and a hypothetical problem is solved. It is to be noted that the technique is not restricted solely to the turbine problem, but can be applied to any steady-state problem which satisfies the specified conditions. Additional analog examples are cited, including techniques for determination of the velocity and pressure distribution around the turbine blade and the temperature distribution in an air-cooled turbine disk.
Empirical determination of severe trauma in seals from collisions with tidal turbine blades
