欢迎访问过程工程学报, 今天是

过程工程学报 ›› 2019, Vol. 19 ›› Issue (2): 289-296.DOI: 10.12034/j.issn.1009-606X.218300

• 流动与传递 • 上一篇    下一篇

水基石墨烯纳米流体在矩形小槽道内的流动换热特性

刘 东*, 舒 宇, 胡安杰   

  1. 西南科技大学土木工程与建筑学院,四川 绵阳 621010
  • 收稿日期:2018-10-15 修回日期:2018-12-13 出版日期:2019-04-22 发布日期:2019-04-18
  • 通讯作者: 刘东
  • 基金资助:
    国家自然科学基金项目;国家自然科学基金项目;四川省科技创新苗子工程项目

Fluid flow and heat transfer characteristics of water-based graphene nanofluids in small rectangular channels

Dong LIU*, Yu SHU, Anjie HU   

  1. School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China
  • Received:2018-10-15 Revised:2018-12-13 Online:2019-04-22 Published:2019-04-18
  • Contact: Dong -Liu

摘要: 测试了水基石墨烯纳米流体的部分热物性,研究了不同浓度、雷诺数(Re)和加热功率条件下水基石墨烯纳米流体作为换热工质在设计的矩形结构小槽道内的对流换热性能。结果表明,层流状态(Re=500~2000)下,矩形槽道壁面温度随Re增大逐渐降低,随加热功率增大逐渐升高,与常规流体换热特性一致;在相同Re和换热功率条件下,随纳米流体浓度增大,壁温逐渐减小;水基石墨烯纳米流体的换热强度比基液去离子水提升较大,Re=2000、加热功率为210 W时,浓度为0.03wt%的水基石墨烯纳米流体的平均努塞尔数(Nu)为9.3,比基液水提升48.8%;受入口效应影响,沿槽道长度局部对流换热系数逐渐减小,最高可达25674.5 [W/(m2?℃)],较基液水最大可提高39.1%;Re=500~1400时,石墨烯纳米流体的流动换热强度随Re增大明显增强;由实验数据结合理论模型拟合了适用于石墨烯纳米流体对流换热强度的计算式,计算结果与实验结果最大相对误差不超过25%,平均相对误差仅为4.8%。

关键词: 石墨烯, 纳米粒子, 对流, 传热, 微槽道

Abstract: A small rectangular channel was designed and fabricated. The convective heat transfer properties of water-based graphene nanofluids in the channel were experimentally investigated by using it as the heat transfer medium under different experimental conditions [different mass concentrations, Reynolds numbers (Re) and heating powers], and some thermal properties of water-based graphene nanofluids were tested. The experimental results showed that the temperature along the wall of rectangular channel decreased with the increase of Re and increased with the increase of heating power under laminar flow (Re=500~1000). This change regulation was consistent with the heat transfer characteristics of conventional fluids, however, with the increase of mass concentration of nanofluids at same Re and heating power, the wall temperature decreased gradually because of the Brownian motion of graphene nanoparticles, the enhancement of scrambling by mixing of particles and the enhancement of thermal properties of nanofluids. The heat transfer intensity of water-based graphene nanofluid was higher than that of deionized water. When Re was 2000 and heating power was 210 W, the average Nusselt number (Nu) of water-based graphene nanofluids with 0.03wt% concentration was 9.3, which was 48.8% higher than that of the based water under the same conditions. Under the influence of inlet effect, the local convective heat transfer coefficient along the channel length decreased gradually, and the maximum local heat transfer coefficient of nanofluid increased by 39.1% compared with the deionized water. The flow heat transfer intensity of graphene nanofluids was obviously enhanced by the Brownian motion of graphene particles at certain Re (500~1400). In order to describe the heat transfer characteristics of water-based graphene nanofluids more clearly, a heat transfer relation was fitted by combining experimental data and theoretical models. Compared with the experimental results, the maximum relative error (MRE) was less than 25%, and the mean relative error was only 4.8%.

Key words: graphene, nanoparticles, convection, heat transfer, microchannel