Spatial variability and quantitative characterization of thermal shock damage in sandstone under different cooling temperatures

This research employs micro-CT scanning technology to analyze the porosity, pore fractal dimension, and spatial variability of sandstone preheated to 600 °C and subsequently cooled in water at varying temperatures (20 °C, 60 °C, 100 °C). The study investigates the mechanisms by which various factors influence thermal shock damage, focusing on the effects of cooling water temperature and the boiling phase transition. The objective is to develop a method for characterizing thermal shock damage that considers spatial variability. The findings indicate that thermal shock damage is limited to a shallow depth beneath the surface, with increased severity near the surface. The boiling phase transition significantly enhances the convective heat transfer coefficient, resulting in substantially higher thermal shock damage when cooled with 100 °C boiling water compared to 20 °C and 60 °C water. Furthermore, for the entire specimen, heating damage exceeds thermal shock damage, and the influence of thermal shock diminishes as specimen size increases. This study addresses the limitations of traditional methods for assessing thermal shock damage that disregard spatial variability and provides practical guidance for engineering projects to manage thermal shock damage more effectively.