Effect of Uncooled Inlet Length and Nozzle Convergence Angle on the Turbulent Boundary Layer and Heat Transfer in Conical Nozzles Operating With Air

Nozzle boundary layer and heat transfer measurements are presented for nozzles having half angles of convergence of 30 and 60 deg, each operating in conjunction with a short and long uncooled pipe inlet. The long inlet, which produced a fully developed turbulent boundary layer at the nozzle entrance, did not significantly alter the nozzle heat transfer distribution relative to values obtained with the short pipe inlet. Peak heat transfer coefficients for the high convergence nozzle were nearly 40 percent higher than the peak value for the 30 deg half angle of convergence nozzle. Measured heat transfer coefficients were compared to predictions based on a boundary layer theory and a pipe flow type correlation.