...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Heat Transfer >Experimental Model of Temperature-Driven Nanofluid
【24h】

Experimental Model of Temperature-Driven Nanofluid

机译：温度驱动纳米流体的实验模型

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This paper presents a systematic experimental method of studying the heat transfer behavior of buoyancy-driven nanofluids. The presence of nanoparticles in buoyancy-driven flows affects the thermophysical properties of the fluid and consequently alters the rate of heat transfer. The focus of this paper is to estimate the range of volume fractions that results in maximum thermal enhancement and the impact of volume fraction on Nusselt number. The test cell for the nanofluid is a two-dimensional rectangular enclosure with differentially heated vertical walls and adiabatic horizontal walls filled with 27 nm Al_2O_3-H_2O nanofluid. Simulations were performed to measure the transient and steady-state thermal response of nanofluid to imposed isothermal condition. The volume fraction is varied between 0% and 8%. It is observed that the trend of the temporal and spatial evolution of temperature profile for the nanofluid mimics that of the carrier fluid. Hence, the behaviors of both fluids are similar. Results shows that for small volume fraction, 0.2 ≤ φ ≤ 2% the presence of the nanoparticles does not impede the free convective heat transfer, rather it augments the rate of heat transfer. However, for large volume fraction φ > 2%, the convective heat transfer coefficient declines due to reduction in the Rayleigh number caused by increase in kinematic viscosity. Also, an empirical correlation for Nu_φ as a function of φ and Ra has been developed, and it is observed that the nanoparticle enhances heat transfer rate even at a small volume fraction.
机译：本文提出了一种系统的实验方法，用于研究浮力驱动的纳米流体的传热行为。浮力驱动流中纳米颗粒的存在会影响流体的热物理性质，因此会改变热传递速率。本文的重点是估计导致最大热增强的体积分数范围以及体积分数对Nusselt数的影响。纳米流体的测试单元是一个二维矩形外壳，具有垂直加热的垂直壁和装有27 nm Al_2O_3-H_2O纳米流体的绝热水平壁。进行仿真以测量纳米流体对施加的等温条件的瞬态和稳态热响应。体积分数在0％至8％之间变化。观察到，纳米流体的温度分布的时间和空间演变的趋势模仿了载流体的趋势。因此，两种流体的行为是相似的。结果表明，对于小体积分数（0.2≤φ≤2％），纳米颗粒的存在不会阻碍自由对流传热，而是会提高传热速率。但是，对于大体积分数φ> 2％，对流传热系数由于运动粘度增加而引起的瑞利数减少而降低。而且，已经开发出Nu_φ作为φ和Ra的函数的经验相关性，并且观察到即使在小体积分数下，纳米颗粒也提高了传热速率。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号