Effect of Spray Pressure and Height on Interfacial Heat Transfer of H13 Steel during Spray Cooling

To accurately calculate mold temperature field during spray process of die casting process, the interfacial heat transfer coefficient (IHTC) between the mold and the spray medium is an extremely important thermo-physical parameter. In this paper, a spray experiment was conducted with different spray pressures and heights, in which the temperature history throughout the spray cooling process of H13 steel plate was recorded. The IHTC under the different spray parameters were calculated by utilizing the nonlinear estimation method. The interface morphology and heat transfer characteristics within the spray cooling process were studied, and the influence of spray pressures and heights on the IHTC was discussed. The results show that the interface can be divided into wet and dry regions, where the former significantly affects the heat transfer behavior on the interface. It is found that high spray pressure has a positive effect on improving peak IHTC whereas it impedes the expansion of wet region and delays the peak of IHTC; reducing spray height leads to the expansion of wet region and the rise of peak IHTC.