Laminarization of a Turbulent Boundary Layer in Nozzle Flow—Boundary Layer and Heat Transfer Measurements With Wall Cooling

Abstract

Boundary layer and heat transfer measurements are presented for flow through a cooled, conical nozzle with a convergent and divergent half-angle of 10 deg for a wall-to-total-gas temperature ratio of about 0.5. A reduction in heat transfer below values typical of a turbulent boundary layer was found when values of the parameter K = (μe /ρe u_e²) (due /dx) exceeded about 2 to 3 × 10−6 . The boundary layer measurements, when viewed in conjunction with the heat transfer measurements, reveal the complicated nature of the flow and thermal behavior and their interrelationship when laminarization occurs.