| The feasibility of using water source heat pump technology in the utilization of waste heat in coal mines has been verified.In the production and mining process of coal enterprises,a large amount of mine water with suitable temperature and stable water supply is generated,making it a very ideal cold and heat source for heat pump systems.On the other hand,currently coal enterprises often use boiler systems to meet the heating needs of mining areas,resulting in huge energy consumption and serious environmental pollution.Therefore,heat pump technology can be applied to coal production enterprises to recover waste heat from mine water,reducing energy consumption and environmental impact,which has significant practical significance for achieving energy-saving and emission reduction under the carbon peaking and carbon neutrality goals.Mine water is different from common cold and heat sources of water source heat pumps,and the water quality is relatively special.During actual operation,mine water heat exchangers are prone to scaling,blockage,and corrosion on the pipe walls.Therefore,this article proposes to use corrugated tubes as heat transfer elements,design and strengthen heat exchange structures to improve the heat exchange efficiency of the heat exchanger,and improve the thermal efficiency and economy of the mine water source heat pump system.This article focuses on the mine water heat exchanger in the mine water source heat pump system.The corrugated tube heat exchanger is used to analyze its flow and heat transfer characteristics through numerical and experimental research.A TRNSYS simulation model of the mine water source heat pump system is built to analyze the changes in heating capacity,equipment power,and system COP value of the heat pump system after the use of corrugated tubes.The main work of the thesis is as follows:(1)A numerical model of the corrugated tube heat exchanger was established,and the flow characteristics of the fluid inside the corrugated tube heat exchanger were analyzed.The study showed that the overall flow on the shell side of the heat exchanger was a Z-shaped cross flow,and the turbulent flow was suddenly enhanced,resulting in a significant pressure drop.Moreover,due to the sudden increase in turbulence,the heat transfer on the shell side was very uneven,with a clear heat transfer dead zone.The turbulent kinetic energy in the area near the wall of the corrugated tube varies significantly,and the turbulent kinetic energy of the fluid on the tube side in the corrugated structure is significantly higher than that in the surrounding fluid area,forming a local strong turbulent zone.(2)The influence of the inlet flow rate of mine water and the inlet flow rate of intermediate water on the temperature of pipeline side fluid and shell side fluid was studied.It is clear that the increase of mine water inlet velocity promotes the heat transfer of the heat exchanger.The corrugated tube heat exchanger is compared with the smooth tube heat exchanger.Compared with the traditional smooth tube heat exchanger,the corrugated tube heat exchanger has better comprehensive performance.When the Reynolds number of the tube side inlet is smaller,the corrugated tube heat exchanger has better enhanced heat transfer effect.(3)An experimental device for analyzing the heat exchanger of mine water corrugated tube was built,and the effects of inlet temperature and flow rate on the comprehensive heat transfer performance of corrugated tube were studied.Research shows that as the inlet temperature of the intermediate water gradually increases,the comprehensive heat transfer coefficient of the heat exchanger gradually decreases.When the Reynolds number of the intermediate water inlet increases,the PEC value of the heat exchanger decreases gradually.As the inlet temperature of the mine water gradually increases,the PEC value of the heat exchanger also gradually increases.(4)Established a TRNSYS simulation model for the mine water source heat pump system,and compared and analyzed the heating capacity,equipment power,and system COP value of the heat pump system using corrugated tube heat exchangers and light tube heat exchangers.After using a corrugated tube heat exchanger in the mine water source heat pump system,the system’s heating capacity,equipment power,and system COP value all increase,effectively improving the overall performance of the heat pump system.This thesis has 48 figures,7 tables,and 109 references. |
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