Similarity criteria for advanced cooling of deep mines based on synergetic mining of mine geothermal energy

Abstract

Often there is limited ability to undertake full scale field trials to develop advanced cooling systems for deep mines. In this situation, physical similarity simulation experiments can help develop the systems. The reduced-size experimental results need to be scaled up to the field scale with the help of similarity criterion. To address the serious thermal hazard problem in deep mine mining, an advanced geothermal exploitation cooling system model based on synergetic mining of mine geothermal energy was developed, along with a physical similarity simulation platform. To obtain the similarity criterion of the system, the mathematical model of the system was established according to the coupling relationship of thermos, hydro, and mechanical fields. Using the equations derived from the mathematical model, the similarity criterion ratio of the system was calculated by equation analysis. The experiment was carried out on the experimental platform, and the numerical model was established by COMSOL Multiphysics numerical simulation software based on the experimental parameters. The accuracy of the numerical model was validated by comparing the experimental results. Full-size and reduced-size models were established, and model parameters were set according to the similarity criteria. The production water temperature and the displacement, stress, seepage speed, and temperature of the two models were compared and analysed. The maximum relative difference was only 0.43% across all parameters, demonstrating the high accuracy and feasibility of the similarity criterion ratio. Using the similarity criterion ratio, the model was validated in the laboratory and the results can be utilized in actual mine design.