Turbulent heat transfer in single phase jet impingement flow over a horizontal dis

The flow and heat transfer characteristics of a turbulent submerged air jet impinging on a horizontal flat surface is studied. Here the inverse heat conduction problem (IHCP) is solved to calculate the temperature and heat flux on the surface. The primary aerodynamics that influence the heat transfer are shown to be the turbulent fluctuations of the free stream velocity. Two regions with distinct flow characteristics are observed, the impingement or stagnation region, and the wall-jet region. Heat transfer relations are derived for each region, based on the assumption that the sum of the laminar and turbulent component of heat flux approximates the total wall heat flux. The laminar component, $hsb{lam},$ of the heat transfer coefficient agrees well with published data. The turbulent component, $hsb{tur},$ in the stagnation and wall-jet region are shown to vary linearly with the root mean square value of the fluctuating component of velocity, $uspprime.$ Unlike the stagnation region, $hsb{tur}$ in the wall-jet region shows dependence on the nozzle Reynolds number, $Resb{D}.$ The results show that for flows with very high free stream turbulence with a turbulence intensity Tu $>$ 0.2, h can be described as a function of $uspprime$ in the free stream, in the wall-affected region under a non-isothermal boundary condition. In other words, regardless of the flow geometry, boundary conditions and the mechanism by which the turbulent fluctuations are created, $uspprime$ determines the heat transfer coefficient. (Abstract shortened by UMI.).