Effect of Internal Structure of Nozzle on Impingement Heat Transfer Performance of Single-beam Water Jet

Ultra-fast cooling (UFC) equipment is an important means to produce high-quality hot-rolled steel materials. Nozzle is the key component of the UFC equipment, which has great influence on the cooling performance. In this paper, the influence of internal structure of the nozzle on the heat transfer performance of water jet impingement was studied experimentally, so as to obtain an excellent nozzle structure. Under the same inlet pressure and outlet flow of the nozzle, heat transfer experiments were carried out on a 750 degrees C stainless steel plate. During the experiment, the actual flows of the nozzles and the temperatures inside the steel plate were recorded. Flow coefficients of the nozzles, surface temperatures and surface heat flux of the steel plate were calculated. Experimental results showed that the flow coefficient of the 30 degrees nozzle was the largest, followed by the 13.4 degrees nozzle, and then the 45 degrees nozzle. It could be found that, under the same inlet pressure, heat transfer performance was positively related to the flow coefficient of the nozzle. Moreover, under the same outlet flow, the heat transfer performance of each nozzle was very similar. Overall, the heat transfer performance of the 30 degrees nozzle was excellent and recommended to be used preferentially in the UFC equipment.