Pressure drop and coefficients of internal heat transfer necessary for transpiration cooling
Abstract
The pressure drop and the coefficients of internal heat transfer necessary for transpiration cooling of hightemperature turbine nozzles and blades with the use of porous materials are calculated semiempirically. Equating the empirical hydraulic drag coefficient in pores zeta = 420/Re sub d (Re sub d  Reynolds number for air in pores) to the theoretical hydraulic drag coefficient in pores zeta  d delta P/1/2 rho bar (V sup 2) delta yields the pressure drop delta P=1/2 rho bar (V sup 2) delta zeta/d = 210 G mu delta/rho (d sup 2)2 (rho, mudensity and dynamic viscosity of air at mean temperature and mean pressure, bar V  velocity of air in pores, delta  thickness of porous layer, d  diameter of pores, G  flow rate of air per unit surface area, 2  porosity factor).
 Publication:

USSR Rept Eng Equipment JPRS UEQ
 Pub Date:
 March 1985
 Bibcode:
 1985RpEE........85D
 Keywords:

 Cooling;
 Heat Transfer;
 Nozzles;
 Transpiration;
 Turbine Engines;
 Aerodynamic Coefficients;
 Porosity;
 Pressure Reduction;
 Viscosity;
 Fluid Mechanics and Heat Transfer