According to the macroscopic definition formula of interface heat transfer coefficient, it is necessary to know the temperature T1 of mold unit 1 when the interface heat flow and the surface temperature ofare known. The temperature T1 of unit 1 at the interface of sand mold and sand core is inversely calculated through the prepared interface heat exchange inverse calculation program. The dotted line temperatures in Figures 1, 2, 3 and 4 are the temperature T1 of the No. 1 unit of the sand mold and sand core obtained by inverse calculation. In order to facilitate the observation of the temperature change of the No. 1 unit, the solid line is the measured temperature of the thermocouple near the inverse calculation interface.
As can be seen from the above figures 1 – 4, the temperature T1 of sand mold No. 1 unit obtained by inverse calculation is between the measured surface temperature Tc1 of sand casting and the measured thermocouple TC2, and the temperature T1 of sand core No. 1 unit is between the measured surface temperature TC5 of sand casting and the measured thermocouple TC6. This is because unit 1 is between two thermocouples, and the temperature curve of sand mold and sand core also conforms to the law of heat transfer. In the initial stage, the heat flow is very large and the temperature rises rapidly; With the decrease of the overall temperature difference, the interfacial heat flow gradually decreases and the temperature change rate slows down; The temperature of unit 1 obtained by inverse calculation is also the key to solve the interface heat transfer coefficient. Given the heat flow Q and the interface temperatures Tc1 and TC5 of sand castings, it can be obtained according to the macro formula of solving the interface heat transfer coefficient, and its accuracy also directly affects the accuracy of the interface heat transfer coefficient obtained by inverse calculation.