An experimental study of local heat transfer using high Prandtl number liquid jets

An experimental investigation was performed to determine the local value of heat transfer coefficient with a free-surface axisymmetric downward jet lubricating oil impinging on fixed plate. A large range Prandtl numbers considered (148<Pr<925) in order fill data gap highly viscous fluids, especially regarding measurements. In Reynolds (170 < Re 2225), dependencies similar literature were identified for laminar and turbulent regimes. significant influence injector diameter (1, 2 4 mm) exchanges found, but nozzle-to-target distances (5<z/d<20) showed no particular effect. Local mean values Nusselt number correlated by taking into account above-mentioned parameters. Nevertheless, exploitation that warming thin liquid film over plate, which is dependent heating flux evacuate, should be taken fluids such as oils; induced changes viscosity lead divergencies measured exchanges. methodology based empirical observation developed take this phenomenon consideration.