Heat transfer characteristics for double water‐jets on thick plates with various jet velocities and heights

During cooling, the array jet impact can achieve a rapid and uniform cooling of the high-temperature plate. Previous research results mostly focused on single-jet cooling of thin plates, but the complex flow and heat transfer characteristics between multiple jets could not be obtained. To clarify the heat transfer mechanisms and cooling speed fields characteristics in different flow regions, double water-jet impingement experiments were carried out on an AISI 304 austenitic stainless-steel plate with a thickness of 50 mm. The jet exit velocity was set to 2.95, 5.90, 8.06, and 11.80 m/s, while the jet height was set to 50, 150, 250, 350, and 450 mm. Pure water was selected as the working fluid with a constant temperature of 12.8 °C. The results show that a complex trend with sequential increasing, decreasing, and increasing behaviors appears in the wetting front width, upon increasing the wetting region diameter. The confluence fluid was found to reduce the influence caused by different jet velocities and to increase the influence caused by different jet heights. In addition, it was found that an excessive amount of accumulated fluid reduces the heat transfer efficiency during transition boiling. Finally, the correlations between maximum heat flux and average maximum cooling speed were established, which provide useful data for optimizing the cooling technology.