Summary: Transpiration and film cooling promise to be effective methods of cooling gas-turbine blades; consequently, analytical and experimental investigations are being conducted to obtain a better understanding of these processes. This report serves as an introduction to these cooling methods, explains the physical processes, and surveys the information available for predicting blade temperatures and heat-transfer rates. In addition, the difficulties encountered in obtaining a uniform blade temperature are discussed, and the possibilities of correcting these difficulties are indicated. Air is the only coolant considered in the application of these cooling methods.

Abstract: The permeability characteristics and tensile strength of a porous material developed from stainless-steel corduroy wire cloth for use in transpiration-cooled walls where the primary stresses are in one direction were investigated. The results of this investigation are presented and compared with similar results obtained with porous sintered metal compacts. A much wider range of permeabilities is obtainable with the wire cloth than with the porous metal compacts considered and the ultimate tensile strength in the direction of the primary stresses for porous materials produced from three mesh sizes of wire cloth are from two to three times the ultimate tensile strengths of the porous metal compacts.

Abstract: An experimental investigation was conducted to obtain information on air-flow uniformity and pressure-level effects for various meshes of stainless-steel corduroy wire cloth, and permeability and strength data for a 20- by 20-mesh stainless-steel wire cloth. It was found that close control of the wire cloth thickness yielded sufficiently uniform air flow and that available methods may be used to predict the effect of pressure level. Permeability and strengths of the 20- by 20-mesh wire cloth were similar to those already available from other meshes. The reduced tensile strength of the 20- by 20-mesh wire cloth in the direction of the primary stresses is one and a half to three times as great as the strength of the best porous sintered materials presently available.