CONJUGATE HEAT-TRANSFER ANALYSIS WITH SUBCOOLED BOILING FOR AN ARC-HEATER WIND-TUNNEL NOZZLE

A method for unsteady, axisymmetric, conjugate heat transfer analysis has been developed The conjugate heat transfer domain comprises co-flo wing high-temperature air and subcooled water coolant on opposite side s of a copper-zirconium, converging nozzle. Heat transfer through the nozzle wall is characterized by solid-body conduction with convection boundary conditions along the air sine and water side of the nozzle wa lt The air-side heat transfer is characterized by forced convection wi th a turbulent boundary layer The water-side heat transfer is characte rized by forced-convection subcooled nucleate boiling. Convective heat transfer coefficients on each side of the nozzle wall are functions o f the wall temperature and the respective flow properties thus couplin g the three regions of the domain. The solution method marches in time , solving at each time step for the nozzle wall temperature distributi on, the flow properties on each side of the nozzle walt! and for the c onvective heat transfer coefficients. The algorithm terminates when ei ther the steady state is achieved or nozzle wall failure conditions ar e reached Solutions are obtained for four test cases culled from the r un history of the Arnold Engineering Development Center HEAT-H1 Test U nit. Results show that the recorded test case failures were not caused by precritical boiling effects. Conclusive failure analysis for the H EAT-HI test cases awaits application of an appropriate convective boil ing critical heat flux model, along with creep and stress-rupture mode ls for the nozzle wall.