地热换热器的传热分析

本文综述了作者近年来在地热换热器传热模型方面的研究:提出了分析竖直埋管地热换热器钻孔内的传热过程的准三维模型,考虑流体工质在深度方向上的温度分布,给出钻孔内热阻的解析表达式;求得有限长线热源在半无限大介质中的瞬态温度响应解析解;导得了有渗流时无限大介质中线热源温度响应的解析解。以上工作改进和深化了国际上现有的地热换热器传热模型,并已应用于工程设计和模拟。

HEAT TRANSFER ANALYSIS OF GROUND HEAT EXCHANGERS

This paper summarizes the authors' study on heat transfer analyses of the ground heat exchangers (GHE). First, taking the fluid axial convective heat transfer and thermal "short-circuiting" among U-tube legs into account, a quasi-3-D model for boreholes in GHEs is established, and analytical solutions of the fluid temperature profiles along the borehole depth have been obtained. Secondly, an explicit solution of the transient 2-D temperature response in a semi-infinite medium with a line-source of finite length has been derived to take the place of the Kelvin's 1-D line-source model. Finally, an explicit solution is also obtained for a line heat source in an infinite porous medium with water advection. These models are helpful to improve GHE design procedures, and are yet suitable for engineering applications.