• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>International Journal of Heat and Mass Transfer >A numerical study of nanofluid natural convection in a cubic enclosure with a circular and an ellipsoidal cylinder
【24h】

A numerical study of nanofluid natural convection in a cubic enclosure with a circular and an ellipsoidal cylinder

机译：具有圆形和椭圆形圆柱体的立方外壳中纳米流体自然对流的数值研究

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

In this paper we develop a numerical method and present results of simulations of flow and heat transfer of nanofluids. We consider a heated circular and elliptical cylinder in a cooled cubic enclosure. Natural convection, which drives the flow, and heat transfer are simulated for different temperature differences and enclosure inclination angles. Steady laminar regime is considered with Rayleigh number values up to a million. Al_2O_3,Cu and TiO_2 nanofluids are considered, as well as pure water and air for validation purposes. Properties of nanofluids are considered to be constant throughout the domain and are estimated for different nanoparticle volume fractions (0.1 and 0.2). In order to simulate nanofluids, an in-house numerical method was developed based on the solution of 3D velocity-vorticity formulation of Navier-Stokes equations. The boundary element method is used to solve the governing equations. In the paper, special consideration is given to the estimation of the boundary value of vorticity on an arbitrary curved surface. The results show highest heat transfer enhancement in the conduction dominated flow regime, where the enhanced thermal properties of nanofluids play an important role. When convection is the dominant heat transfer mechanism, the using nanofluids yields a smaller increase in heat transfer efficiency. Comparison of 2D and 3D results reveals consistently lower heat transfer rates in the 3D case. As the enclosure is tilted against gravity, the flow symmetry around an elliptical cylinder is lost and the overall heat transfer increases.
机译：在本文中，我们开发了一种数值方法，并给出了纳米流体流动和传热模拟的结果。我们考虑在冷却的立方外壳中加热的圆形和椭圆形圆柱体。对于不同的温差和外壳倾斜角度，模拟了驱动气流的自然对流和传热。稳态层流状态被认为瑞利数值最高为一百万。考虑到Al_2O_3，Cu和TiO_2纳米流体以及纯水和空气，以进行验证。纳米流体的性质在整个域中被认为是恒定的，并针对不同的纳米颗粒体积分数（0.1和0.2）进行了估算。为了模拟纳米流体，基于Navier-Stokes方程的3D速度涡度公式的解法，开发了一种内部数值方法。边界元法用于求解控制方程。在本文中，特别考虑了在任意曲面上涡旋边界值的估计。结果表明，在以传导为主的流态中，传热增强最大，其中纳米流体的增强的热性能起着重要的作用。当对流是主要的传热机制时，使用纳米流体会产生较小的传热效率增加。 2D和3D结果的比较表明，在3D情况下，传热速率始终较低。随着外壳克服重力倾斜，椭圆形圆柱体周围的流动对称性消失，总的热传递增加。

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