English

应用科学学报 ›› 1999, Vol. 17 ›› Issue (3): 327-333.

• 论文 • 上一篇    下一篇

非牛顿幂律流体自由降膜流的换热特性

蒋章焰1, 陶正文2, 阎维平3   

  1. 1. 中科院工程热物理研究所;
    2. 中科院电工研究所;
    3. 华北电力大学
  • 收稿日期:1997-08-24 修回日期:1998-02-27 出版日期:1999-09-30 发布日期:1999-09-30
  • 基金资助:
    国家自然科学基金资助项目

Heat Transfer to Non -Newtonian Power-Law Fluid Freely-Falling Film Flow

JIANG ZHANGYAN1, TAO ZHENGWEN2, YAN WEIPING3   

  1. 1. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100080;
    2. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080;
    3. North China University of Electric Power, Baoding 071003
  • Received:1997-08-24 Revised:1998-02-27 Online:1999-09-30 Published:1999-09-30

PDF

58

被引次数

4

摘要： 对垂直加热管外非牛顿幂律流体自由降膜流的换热特性进行了实验研究.实验液体是质量分数为8000×10-6的羧甲基纤维素钠(CMC)水溶液,经测定其流变参数,表明幂律模型适合于表征其流变特性.以稳定层流物理数学模型为依据,整理试验数据,给出平均努赛尔数随变型雷诺数和变型普朗特数而变化的综合关系式.文中还给出流变参数随温度而变化的拟合公式.

关键词: 传热, 非牛顿流体, 薄膜流

Abstract: The objective of the present paper is to study experimentally the heat transfer to non-Newtonian power-law fluid falling films flowing down the outside surface of a vertical stainless steel tube which has 20mm in outside diameter, 1mm in thickness, and 1100mm in length. The test liquid is an aqueous solution of carboxymethycellulose sodium(CMC solution) with the concentration of 8000×10-6 (mass ratio). Rheological parameters of the solution were measured by the NXS -11 rotational viscosimeter within t=15~85℃ and empirical formulae for the variation of the parameters with solution temperatures are given as follows:n=0.644+0.245×10-2 t, K=1.365exp(-0.0305 t), where n is the flow behavior index and K is the consistency coefficient. Based on a simplified physical model, the correlation of the average Nusselt number as a function of the modified Reynolds number and the modified Prandtl number can be obtained by fitting the test data. The correlation is given as follows:Nupl=2.0 Repl0.395 Prpl1/3.

Key words: non-Newtonian fluid, thin film flow, heat transfer