Abstract: The aim of this research is to investigate the impact of liner seal cracking on the two-phase seepage and heat transfer characteristics of fractured surrounding rock in compressed air energy storage (CAES) cavern. A dual-media two-phase seepage calculation program was developed and validated based on a weak form of PDE using COMSOL. On this basis, a numerical model was constructed to examine the impact of liner cracking on two-phase seepage and heat transfer characteristics in the fractured rock mass during gas charging and discharging processes. The findings reveal that liner cracking induces an increase in seepage pressure within both the fractures and pore spaces of the surrounding rock, and consequently leads to an amplified seepage pressure difference between the fractures and pore spaces, with a maximum pressure difference increase of 1.5 MPa. Over a period of 210 days of operation, liner cracking results in the expansion of the horizontal gas diffusion range from 54 m in the absence of cracking to 66.7 m. Under the initial gas charging and discharging conditions, a significant temperature difference exceeding 100 K can be observed between the inner and outer sides of the liner. However, liner cracking and fractures in surrounding rock exhibit minimal effects on the temperature distribution of both the liner and the surrounding rock. It is evident that while liner cracking facilitates seepage pressure diffusion, its impact on temperature distribution remains negligible.

Key words: compressed air energy storage, dual-media, two-phase seepage and heat transfer, COMSOL weak form, fractured rock mass