摘要
根据工程中群桩埋管换热器状况,采用叠加原理计算群桩埋管的桩壁温度,定义能源桩埋管换热器的热响应半径为周围其他桩引起的过余温度影响系数≤5%时相邻桩中心线之间的垂直距离;在大量计算分析的基础上,采用最小二乘法拟合出单工况荷载作用下能源桩埋管换热器热响应半径计算公式;考虑到实际能源桩工程系统运行时每延米换热功率是关于时间的函数,建立动态负荷作用下能源桩三维传热数值模型,分析不同荷载分布形式、峰值负荷、运行时间以及全生命周期对能源桩热响应半径的影响。研究结果表明:在单桩、单排桩、双排桩和多排桩布置状况下,本文拟合公式的热响应半径计算结果与无限长线热源模型解析解之间的最大相对误差分别为4.62%,4.45%,3.77%和3.32%,说明该方法具有较高的计算精度,符合工程要求;荷载分布形式以及峰值负荷仅影响桩周岩土体中过余温度及其梯度,桩周岩土体热扩散系数及运行时间影响温度传递范围;根据工程中最常见的多排桩布置方式,得到不同桩径和不同岩土体热扩散系数条件下能源桩热响应半径随时间的变化关系,可为工程应用提供参考。
According to the condition of pile-group buried heat exchanger in engineering,the temperature of pilegroup buried heat exchanger was calculated by superposition principle,and the thermal response radius of pilebased buried heat exchanger was defined as the vertical distance between center lines of adjacent piles when the excess temperature influence coefficient caused by other piles was less than or egual to 5%.On the basis of a large number of calculation and analysis,the calculation formula for thermal response radius of energy pile buried heat exchanger was fitted using the least squares method under working condition of single load response.In view of the actual energy pile,per linear meter heat power of engineering system in running time was a function of time,energy piles three-dimensional heat transfer numerical model was set up under the action of dynamic load,and the the influences of different load distribution forms,peak load,running time and the whole life cycle on the thermal response radius of energy pile were analyzed.The results show that in cases of single pile,single row,double row piles and pile arrangement,the maximum relative error between thermal response radii obtained from the proposed formula and analytical solution of infinite long heat source model are 4.62%,4.45%,3.77% and 3.32%,respectively.The method has higher accuracy and can meet the demands of engineering.The load distribution form and size of the peak load only affect the excess temperature and gradient in the surrounding rock mass,while pile rock and soil body heat diffusion coefficient and temperature area are influenced by operation time.According to the most common arrangement of multi-row piles in practice,the relationship between thermal response radius of energy piles with time under different pile diameters and different thermal diffusivity of rock-soil mass is plotted,which provides reference for the engineering application.
作者
王哲
刘耶军
张正威
翁凯文
郑秀玲
许四法
WANG Zhe;LIU Yejun;ZHANG Zhengwei;WENG Kaiwen;ZHENG Xiuling;XU Sifa(School of Civil Engineering,Zhejiang University of Technology,Hangzhou 310014,China;School of Landscape Architecture,Zhejiang Agriculture and Forestry University,Hangzhou 311300,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第2期514-522,共9页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51778585)~~
关键词
热响应半径
计算模型
能源桩
数值模拟
传热特性
thermal response radius
calculation model
energy pile
numerical simulation
heat transfer characteristics
