HEAT TRANSFER ENHANCEMENT FROM A WIRE TO AN IMPINGING UPWARD SUBMERGED SLOT JET OF WATER IN SUBCOOLED AND SATURATED BOILING CONDITIONS

Experimental data about the heat transfer from a heated 0.25 mm in diameter nickel wire to a submerged upward flow slot jet of distilled water are reported. The tests are carried on in forced convection regime, in sub-cooled and saturated boiling conditions. The influence on the heat transfer rate of different parameters is investigated, such as the jet exit velocity, the distance between the slot exit and the wire and the heat transfer regime, in particular the sub-cooling degree. The choice of the nickel is due to the opportunity to operate in a wide range of the jet exit velocity, thanks to its mechanical and thermometric characteristics. The main aim of this research was to find out the optimal conditions, in order to maximize the heat transfer coefficient enhancement, and moreover, to make a comparison between other results obtained in the 1990s by the same authors on horizontal circular cylinders, with the diameter one size order bigger than the present wire.