Study On Numerical Simulation Of Heattransfer Characteristics Of Buried Pile Base

Pile spiral heat exchanger as a ground source heat pump system, a new type of undergroundheat exchanger, it not only has the advantages of traditional ground source heat pump system, butalso greatly eased the ground source heat pump systems due to the drilling and more due to thehigh initial investment, it covers an area larger problems[1]. So,it is important to master the pilespiral heat exchanger heat transfer performance to give ground source heat pump system designedparameters。So far, pile spiral pipe heat exchanger performance and design parameters are also very lack.As the study of the soil thermal properties and heat transfer performance that reflect the buriedunderground heat exchanger soil temperature field mainly concentrates in the theoretical stage, norelevant experimental verification, and the simulation of buried base pipe heat pump system ofsoil temperature field is not a lot, which makes the application of research results to some extentlimited. In this context，the paper establishes three-dimensional numerical model of the pile spiralheat exchanger and verify the correctness of the model. Analysising in different inlet temperatureand different velocity of imports, different soil thermal properties, different pile foundationconcrete thermal physical properties, different system running time,the radius of influence to thespiral tube heat. After runing a month, the inlet temperature of310k under the action of thethermal effect of the radius is2.05m; Similarly, after running a month, the import of1.2m/svelocity under the action of the thermal effect of the radius is2.3m. After running ten hours, forthe hot action of soil thermal diffusivity is larger radius is1.36m, and heat of soil thermaldiffusivity of the smaller radius is1m; Likewise for larger thermal diffusivity of concrete thermaleffect radius is1.52m, and thermal diffusivity of concrete low is1.14m, inlet temperature andflow velocity influence on the heat transfer performance of buried pipe pile is small, and thesoil thermal physical property and thermal physical properties on concrete pilefoundation affected by the heat transfer performance of buried pipe. is main. Import velocity can generally control between0.3m/s~0.7m/s. Buried pipe pile foundation is moresuitable for the soil thermal diffusivity larger area, it is important to choose bigger thermaldiffusivity of concrete at the same time.Also compared the analysis phase backfill materials and pile foundation concrete backfillmaterial heat transfer characteristics of the two. Running ten hours and contrast analysis of thehorizontal distribution of the temperature, it is concluded that pile foundation concrete backfillwell gradient of temperature distribution in a phase change material backfill well temperaturegradient is large, hot action radius. Under the condition of same radius of heat from the use ofphase change materials after only54%of the pile foundation concrete heat action radius. Visible,the use of phase change materials backfill can reduce soil thermal disturbance radius. If usingphase change material backfill, which can be narrowed in engineering drilling interval, reduce soilusable floor area.