2018 Volume 58 Issue 1 Pages 132-139
In order for the hot plate TMCP ultra-fast cooling technology to be optimized, the local heat transfer characteristics of multi jet impinging on hot plate surfaces were investigated. The experiments were performed for double and three jet impingement cooling study as cooling header primary units in the industrial scale. The jet velocity at the nozzle exit ranged between 1.99 m/s and 6.63 m/s. The results demonstrated that both the hydrodynamic structure and the heat transfer region distribution of multi jet impingement cooling were distinct from the single jet case. The parallel flows with a sufficient kinetic energy collided and intensified the heat transfer efficiency in the interference region. The higher-sized nozzle spacing magnified the heat exchange differences in the interference region, whereas the jet velocity increased both the heat flux and the rewetting velocity acceleration outside the stagnation region. The surface temperature in the interference region dropped slightly faster than the parallel flow region at the same spatial distance from the stagnant point, second only to the stagnant point, which was interpreted that the parallel flows interaction and agitation enhanced the heat transfer intensity. The results were valuable in the nozzle arrays arrangement and the heat transfer ability and cooling uniformity improvement of the ultra-fast cooling technology in industrial applications.