In-situ diagnosis of heat loads on divertor tungsten targets using laser speckle digital image correlation

Based on a high heat flux (∼300MW) comprehensive experimental platform, this study used the laser speckle digital image correlation (LS-DIC) method to measure the thermal strain of the tungsten target plates from 190°C–2952°C, that was used to invert the temperature field distribution and heat loads of the target plates, realizing the synchronous in-situ measurement of the strains, temperatures and heat loads of the tungsten target plates under extreme high temperature. By comparing with the tungsten thermal strains in literature, the average relative errors of LS-DIC measurement results in different temperature ranges are 2% within 190–1100°C and 6% within 1040–2952°C. The feasibility and accuracy of using LS-DIC to diagnose temperature field and heat loads were verified, the inversion results were compared with Ansys simulation results and actual loading data of heat loads, and the error rates of temperature and heat loads inversion were less than 6% and 7%, respectively. The LS-DIC method proposed in this study is expected to be applied to the non-contact, in-situ measurement of material strain and temperature under extreme environments as well as the inversion of heat loads.