• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Heat Transfer >Dendrite Growth during Freezing of Millimeter-Scale Eicosane Droplets
【24h】

Dendrite Growth during Freezing of Millimeter-Scale Eicosane Droplets

机译：毫米级二十碳烷滴冻结过程中枝晶的生长

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

The freezing characteristics of small diameter eicosane (T_(melt) = 37℃) droplets are studied here for their use in novel dry-cooling strategies based on spray freezing of recirculating phase change materials (PCM). PCM can be used to store thermal energy with relatively small changes in temperature (due to latent heat), as well as volume (due to small density changes). 4.2 mm diameter eicosane droplets are superheated to 40℃, placed on a cold stage at 10℃, and imaged during freezing (a). Similarly, liquid eicosane is enclosed within a custom-built experimental package creating a 5 mm diameter, 100 μm thick disc geometry with a temperature controlled boundary that is rapidly dropped from 40℃ to 10℃ (b). In both cases the liquid-solid interface is tracked, as well as the formation and growth of long dendrite structures which have been observed to play a critical role in the freezing process. (c) and (d) show the vertical position normalized by the droplet height, y/H, and the radial position (measured inward) normalized by the disc radius, r/R, of both the interface location and the average dendrite tip location. The total freezing time is observed visually, resulting in characteristic Fourier numbers of Fo = 0.55 ±0.15 (droplet) and Fo = 3.5 ±0.15 (disc) at identical Stefan numbers of St = 0.3 ±0.03, where the characteristic lengths are taken as the ratio of the eicosane volume to the cooled surface area.
机译：本文研究了小直径二十烷（T_（熔体）= 37℃）液滴的冻结特性，并将其用于基于循环相变材料（PCM）喷雾冻结的新型干冷策略。 PCM可用于存储温度（由于潜热）变化相对较小以及体积（由于密度变化较小）引起的热能。将直径为4.2 mm的二十碳烷液滴过热至40℃，置于10℃的冷台上，并在冷冻期间成像（a）。同样，液体二十烷被封入定制的实验包装中，从而创建了直径为5 mm，厚度为100μm的圆盘几何形状，其温度控制范围从40℃迅速降至10℃（b）。在这两种情况下，都跟踪了液-固界面以及长枝晶结构的形成和生长，观察到它们在冷冻过程中起着关键作用。 （c）和（d）显示了通过液滴高度y / H归一化的垂直位置，以及通过界面位置和平均枝晶尖端位置的圆盘半径r / R归一化的径向位置（向内测量） 。肉眼观察总的冷冻时间，在相同的Stefan数St = 0.3±0.03时，Fo = 0.55±0.15（液滴）的特征傅里叶数和Fo = 3.5±0.15（圆盘），其中特征长度为二十烷体积与冷却表面积之比。

著录项

  • 来源
    《Journal of Heat Transfer》 |2015年第8期|080902.1-080902.1|共1页
  • 作者

    Mahamudur Rahman; Han Hu; Hamidreza Shabgard; Philipp Boettcher; Ying Sun; Matthew McCarthy;

  • 作者单位

    Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA;

    Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA;

    Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA;

    Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA;

    Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA;

    Department of Mechanical Engineering, Drexel University, Philadelphia, PA, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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