TURBULENCE DISSIPATION IN A FREE-SURFACE JET OF WATER AND ITS EFFECT ON LOCAL IMPINGEMENT HEAT-TRANSFER FROM A HEATED SURFACE .1. FLOW STRUCTURE

This study investigates the relationship between jet turbulence and lo cal impingement heat transfer for a free surface, planar jet of water. Employing a thermal anemometer system, measurements of the mean veloc ity and turbulence intensity are reported at different streamwise and spanwise locations throughout the jet. The flow conditions at the nozz le discharge were controlled by using different nozzle designs (parall el-plate and converging) and flow manipulators (wire grid and screens) . Measurements of the velocity gradient along the impingement surface, known to influence heat transfer from analytical considerations of a laminar impinging jet, were also made for the same sets of nozzle cond itions. The test matrix also included variations in the Reynolds numbe r (23,000 and 46,000) and distance from the nozzle discharge to the su rface (0 to 30 nozzle widths). The local heat transfer results corresp onding to the flow structure measurements are reported in Part 2 of th is paper.