Downstream Influence of Film-Cooling in a High-speed Laminar Boundary Layer

Abstract

Nomenclature B = mass injection parameter C f = skin-friction coefficient H e = total enthalpy h -enthalpy K = ratio of enthalpy L = characteristic length M = mass velocity parameter (pvjjpu)q w = heat flux at the wall Re = Reynolds number St = Stanton number T = absolute temperature u = velocity in the stream direction v = velocity in the ^-direction x = coordinate distance measured from actual origin of boundarylayer growth x 0 = length of porous plate 3; = coordinate distance measured perpendicular to surface /? = ratio of enthalpy deficit thickness to momentum thickness 6 = velocity boundary-layer thickness 6 h = enthalpy deficit thickness S T = thermal boundary-layer thickness S L = compressibility factor r\ = film-cooling effectiveness parameter 0 = momentum thickness <f ) = solid-wall effectiveness parameter = dynamic viscosity p = density Subscripts aw = adiabatic wall with coolant injection c = coolant condition • w = wall (local) conditions / = local conditions relative to injectant area o -conditions without injection oo = mainstream flow conditions Theme A METHOD of predicting the downstream effectiveness in a high speed laminar boundary layer has been developed. The unique feature of the analysis is its simplicity, inasmuch as complex computer codes are not required.