The accuracy of the back calculation program needs to be verified. We select the difference between the measured temperature data of thermocouple of flat sand mold casting and 50 / 100mm ring sand mold casting and the back calculation temperature data to verify the accuracy of the back calculation program. For flat sand mold castings, we select the difference ∆ TC2 between the measured temperature TC2 of No. 2 thermocouple in the sand mold and the reverse calculated temperature TM2 for comparison; For 50 / 100mm ring sand mold castings, the measured temperatures TC2 and TC6 of No. 2 thermocouple in the sand mold and No. 6 thermocouple in the sand core are selected, and the difference between the measured temperatures TC2 and TC6 and the back calculation data TM2 and TM6 is used to judge the back calculation accuracy. As shown in Figure 1 and 2.
It is obvious from Fig. 1 and Fig. 2 that the difference between the measured temperature and the back calculated temperature at the thermocouple of flat sand mold casting and ring sand mold casting oscillates greatly in the first 100s, but with the passage of the back calculation time, the calculation error is gradually reduced by the iterative correction of the back calculation program itself. As shown in the figure, before 200s, the maximum absolute difference at TC2 in the sand mold during the solidification of flat plate parts is 8.6 ℃, and the maximum absolute difference between the measured temperature and the calculated temperature at the thermocouple positions of TC2 and TC6 during the solidification of ring sand mold castings is 17 ℃ and 12 ℃ respectively; After 200s, the maximum absolute difference is less than 2 ℃, which shows that the calculation error is optimized and corrected in the back calculation process, so that the back calculation temperature is very consistent with the measured temperature. Therefore, the calculation accuracy of the inverse algorithm used in this paper to solve the temperature field of flat sand mold casting, annular sand mold casting and sand mold (core) indirectly proves that the inverse calculation of interface heat transfer coefficient is accurate and reliable.