摘要
该文旨在分析基于钻孔埋管换热器的热响应测试(thermal response tests,TRT)测试用于桩基埋管换热器时的通用性与局限性。首先选用不同的分析模型进行温度响应的计算与比较,并选用包含流体对流换热的有限元模型(FEM),模拟了不同桩径、不同埋管形式以及不同加热功率的能源桩TRT。计算表明:用于钻孔埋管的TRT测试同样适用于能源桩,但随着桩径的增大,测试所需的最短时间变长;桩内埋管数量的增加和加热功率的提高也不能缩短测试时间。通过模拟北京CFG(cement fly-ash gravel)桩的TRT测试,有限元模型得到了验证。该试验表明:能源桩TRT测试的加热功率不宜过大。对直径大于400 mm的能源桩,TRT测试时长>100h,测试条件不易保证,建议采用原位钻孔取样后实验室测试的方法获取岩土热物性参数。
Thermal response tests （TRT） are used to investigate the thermal properties of the ground for dimensioning borehole heat exchangers, This study analyzes the versatility and limitations of TRT in energy piles. Several analytical solutions are presented for the temperature response of the borehole system with a finite element model （FEM） used to study the effect of convection for different pile diameters, different types of pipes and different heating powers. The results show that the TRT tests can be used in energy piles but the minimum duration of the tests increases with increasing pile diameter, while the types of pipes and the heating power have no effects. The accuracy of the FEM model was verified by simulations of Beiiing TRT tests on CFG （cement fly--ash gravel） piles with the results indicating that the high heating power is not appropriate. TRT tests may take hundreds of hours for large diameter piles （larger than 400 mm）; thus, lab tests for the thermal parameters are suggested using undisturbed borehole samples.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第1期14-20,26,共8页
Journal of Tsinghua University(Science and Technology)
基金
清华-MIT-剑桥三校低碳大学联盟基金资助项目(300907001)
