Experimental Study Of Groundwater Flow And Heat Transfer In Aquifers

Conducting a laboratory simulated experiments research on groundwater flow and heat transfer in confined aquifer could promote the research on the theoretical and experimental aquifer energy storage and underground thermal energy development. Laboratory simulated experiments of groundwater and heat transfer in confined aquifer in this thesis are designed to quantitatively investigate the impact of temperature on the groundwater flow model and heat transfer model of aquifer, and to rederive the governing equations of groundwater flow and heat transfer in aquifer. The results of the experiments are utilized to validate the correctness of the models derived. All tasks are to provide a technical support to groundwater pumping and injection engineering and further to rationalize the development and use of aquifer thermal energy storage, subsequently, and to serve for the practical production. Research work in this thesis includes:(1) Based on the hydrogeological conditions simplified which are required in aquifer energy storage, a doublet-well laboratory simulated experiments system is invented for the pumping with low temperature and injection with high temperature, partly inheriting from a previous research work.(2) After an assembly plan of confined aquifer in porous media and fractured media designed, 12 experiments including pumping test, injection test and doublet-well pumping and injection test with fully and partially penetrating well conditions in porous media and fractured media, respectively.(3) The governing equations of three-dimensional groundwater flow and heat transfer are derived, based on a extensive research on existing mathematical models of aquifer groundwater flow and heat transfer.(4) On the basis of a study of calculation principle of genetic algorithm and tabu search algorithm, a computing programme is made to estimate the parameters of groundwater flow model, with the pumping test data in confined porous media.(5) Three-dimensional finite elements coupled numerical simulations of groundwater and thermal are conducted under a fully penetrating doublet-well pumping and injection test condition in porous and fractured media, respectively. Based on the numerical simulations and analysis, correctness of the computing model derived is validated, and laws of three-dimensional groundwater flow and thermal transfer in porous and fractured media are concluded.Innovation points of the whole research work could be concluded that:(1) A doublet-well laboratory simulated experiments system is developed for groundwater flow and thermal transfer in aquifers.(2) An assembly plan of confined aquifer in orthogonal fractured network media is designed, and experiments of groundwater flow and thermal transfer in confined fractured aquifer are accomplished on the experimental system developed.(3) An algorithm combined genetic algorithm and tabu search algorithm is proposed and employed to identify the parameters of groundwater flow model.(4) Three-dimensional finite elements coupled numerical simulations of groundwater flow and thermal transfer in fractured aquifer are conducted by using a powerful finite elements simulation software, COMSOL Multiphysics, based on the dual-media model.