首页> 外文期刊>International Journal of Heat and Mass Transfer >Numerical and model predictions of the thermal conductivity of bismuth telluride nanoprism-assembled films
【24h】

Numerical and model predictions of the thermal conductivity of bismuth telluride nanoprism-assembled films

机译:碲化铋纳米棱镜组装膜导热系数的数值和模型预测

获取原文
获取原文并翻译 | 示例
           

摘要

This research aims at understanding the heat transfer phenomenon in the Bi_2Te_3 nanoprism-assembled films. For obtaining the associated effective thermal conductivity, the effective-medium-approximation (EMA) models existing in literature were examined and properly modified for prediction and Monte-Carlo numerical experiments based on unstructured grids were performed for confirmation. Cross-plane and in-plane thermal conductivities were both explored. For model predictions, the characteristic grain size of the nanoprisms is defined as either the phonon mean free path purely due to the grain boundary scattering (i.e. excluding the intrinsic scattering) or the averaged hydraulic diameter. A combination of a non-dilute 2D EMA model with the triple bond percolation theory turns out to be the best model for predicting the in-plane thermal conductivity. On the other hand, the evaluation of the cross-plane thermal conductivity by treating the nanoprisms as thermal conductors connected in parallel is satisfactory. The investigation shows that in addition to porosity, the scattering at the grain boundaries plays a dominant role in reducing the heat transfer in the direction perpendicular to the boundaries; the in-plane thermal conductivity is therefore much smaller than the cross-plane one.
机译:这项研究旨在了解Bi_2Te_3纳米棱镜组装薄膜中的传热现象。为了获得相关的有效导热系数,检查了文献中存在的有效介质近似(EMA)模型,并对其进行了适当修改以进行预测,并进行了基于非结构化网格的蒙特卡洛数值实验以进行确认。跨平面和平面内的热导率都进行了探索。对于模型预测,将纳米棱镜的特征晶粒尺寸定义为纯粹由于晶界散射(即,排除本征散射)的声子平均自由程或平均水力直径。非稀释2D EMA模型与三键渗流理论的结合被证明是预测面内热导率的最佳模型。另一方面,通过将纳米棱镜作为并联连接的热导体来评价横断面热导率是令人满意的。研究表明,除孔隙率外,晶界处的散射在减少垂直于晶界方向的传热方面起着主要作用;因此,面内热导率比横截面内热导率小得多。

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