Research on Heat Extraction Enhancement and Increased Production of Super-Long Gravity Heat Pipe Geothermal System Under Forced Convection of Downhole Fluid Withdrawal
Utilizing super long gravity heat pipe to extract deep geothermal resources can effectively mitigate some common issues such as working fluid loss,fouling corrosion,and difficulties in underground connection that exist in enhanced geothermal systems.However,the heat transfer rate of the gravity heat pipe geothermal system is constrained by the low thermal conductivity of the reservoir.This study proposes a forced convective heat transfer scheme involving downhole fluid extraction and injection numerical simulation of fluid flow and heat transfer process between underground heat pipe and heat reservoir.Changes in the flow and temperature fields are obtained,and a comparison is made between the heat extraction performance of stationary and flowing downhole fluids.The impacts of different mass flow rates,extraction-to-injection time ratios,and cycle durations on heat extraction performance are examined.The results indicate that downhole fluid extraction and injection can significantly improve the system's heat extraction performance.Increasing the extraction flow rate of fluid leads to further improvement of the heat extraction rate.The strategy of slow extraction and rapid injection shows a notable enhancement effect in heat transfer rate,where a larger extraction-to-injection time ratio corresponds to better heat extraction performance.Moreover,while maintaining the total heat extraction time constant,prolonging the extraction cycle duration leads to a more pronounced improvement in heat extraction performance.
gravity heat pipeforced convectionheat transfer ratenumerical simulation
万方数据
维普
