纳米流体对U型深埋管换热特性影响的研究

结合西安市某个埋深为2505 m的U型深埋管换热系统,在原位实验验证的基础上建立三维全尺寸数值计算模型,进而模拟分析埋管内热流载体种类对强化埋管换热的效果。埋管内热流载体除常规使用的水外,还选用Al₂O₃/水、CuO/水和SiO₂/水3种纳米流体。通过改变这3种纳米流体的纳米颗粒体积浓度分别为0.1%、0.3%、0.5%及1.0%,分析纳米流体种类及纳米颗粒体积浓度对埋管换热的影响。研究结果表明,就整个埋管的换热而言,纳米流体的强化换热效果较小。因此,通过改变埋管热流载体来达到埋管强化换热的方法并不高效合理。

STUDY ON INFLUENCE OF NANOFLUIDS ON HEAT TRANSFER CHARACTERISTICS OF DEEP-BURIED U-BEND PIPES

Combined with a deep-buried U-bend pipe heat exchange system with a depth of 2505 m in Xi’an,a three-dimensional fullsize numerical model was established on the basis of in-situ experimental verification,and the effect of the heat flow carrier type on heat transfer enhancement of the buried pipe was simulated and analyzed. In addition to the conventional water,three nanofluids,Al₂O₃/water,CuO/water and SiO₂/water,were also selected as the heat flow carriers in the buried pipe. By changing the volume concentration of nanoparticles of the three nanofluids to 0.1%,0.3%,0.5% and 1%,respectively,the influence of the types of nanofluids and the volume concentration of nanoparticles on the heat transfer of buried pipes was analyzed. The research results shown that in terms of the heat transfer of the entire buried pipe,the enhanced heat transfer effect of the nanofluid is very small. Therefore,it is not efficient and reasonable to change the heat flow carrier of the buried pipe to achieve the enhanced heat transfer of the buried pipe.