Heat Transfer Characteristics of Buried Pipe Heat Ex-changer in Bedrock Region based on CFD Numerical Simulation

Yuanyan Zhang

Chongqing Jiaotong University, Chongqing, 400000, China

Abstract: In view of the actual engineering geotechnical stratification， the software FLUENT was used to establish the homogeneous model and the heterogeneous model, and the rock-soil mass temperature distribu-tion around the buried pipe heat exchanger was compared between the two models. The results showed that:The axial temperature distribution of the homogeneous model is uniformly distributed, while the excess temperature of the borehole wall surface of the heterogeneous model is related to the thermal conductivity of the rock-soil layer.The influence radius of the homogeneous model and the heterogeneous model should be determined by the influence radius of the layer with larger thermal conductivity in the geotechnical layer.After the shutdown, the temperature around the rock and soil layer of the homogeneous model recovered quickly, and the temperature recovery rate around the rock and soil layer of the heterogeneous model was related to the thermal physical parameters of the layered rock and soil, ignoring the stratification may lead to local thermal accumulation.

Keywords: Homogeneous model; Heterogeneous model; Excess temperature; Rate of temper-ature recovery