西安地区中深层套管式地埋管换热性能数值模拟

In order to find optimal parameters to promote the heat transfer rate for the coaxial casing heat exchanger in the Xi'an area, we established a three-dimensional geological model in this study, and then simulated the influence of four parameters, that is the inlet water flow rate, inlet water temperature, heat exchange borehole depth, and the outlet inner pipe thermal conductivity, on the heat transfer performance. The results show that:1) Increasing the inlet water flow rate will lead to an increase in heat exchange, but a decrease in outlet water temperature. It is most appropriate to set the inlet flow rate at 15 m³/h~25 m³/h in Xi'an area; 2) Increasing the depth of the heat exchange borehole will cause exponential growth in outlet water temperature and the heat transfer. The influence of borehole depth on the heat transfer mainly depends on the formation temperature and heat transfer duration rather than the thermal conductivity; 3) For the Xi'an area, the inlet water temperature has the most obvious impact on the heat transfer, followed by the thermal conductivity of the outlet pipe, the depth of the heat exchange borehole and the inlet water flow rate. This study is not only significant for the design and construction of the buried pipe heat exchange system, but also for the exploration and development of geothermal energy in Xi'an area.