准稳态平板法测量土壤导热系数

Measurement of thermal conductivity of soil by the heated probe method

鉴于土壤的导热系数对地下电缆载流量和温度场有很大影响,采用带有内热源的镀铬抛光铜管(发热管)来模拟电缆稳态场,根据准稳态平板法原理,搭建土壤导热系数实验台,测量出不同深度的土壤导热系数,得出不同深层和不同含水量分别与导热系数关系的变化曲线。试验研究表明,土壤的导热系数在地下直埋电缆的稳态温度场计算中可以大致地将土壤分为两层,即非干燥层和干燥层,这对直埋电缆温度场计算中土壤导热系数的选取具有指导意义。

On account of the thermal conductivity of soil has great influence on the ampacity and temperature of underground cables,an experimental investigation is made to study the heat dissipation of an electric power cable group.Base on the theory of quasi-steady-state plank method,we have built up a platform to accurately measure the soil’s thermal conductivity of different depth.The curves of the relationship between thermal conductivity and moisture and different depth of soil are obtained.Experimental study demonstrates that the soil of steady-state temperature field can be divided into two layers-dried layer and non-dried layer.It’s meaning for the selection of thermal conductivity of soil in calculation for soil temperature field of underground cable.