平直翅片的数值模拟及结构改进

摘要

利用CFD方法建立计算平直翅片性能的数值模型。为准确模拟湍流区域翅片j和f因子，采用低雷诺数湍流模型；通过UDF方法用Pr_t（湍流普朗特数）模型替代FLUENT软件中默认值（0.85）。计算结果表明：计算j和f因子与实验结果的平均绝对误差分别为6.72%和6.47%。在流动方向的任意横截面上，翅片中心处温度最低，且随着雷诺数增大而降低。翅片中心处与进口流体温差比上下板与进口流体温差低5%~18%。为强化翅片与上（下）板接触区域传热，间隔切除部分翅片，j因子增大2.76%~12.44%，而f因子保持不变。

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关键词：平直翅片；低雷诺数湍流模型；湍流普朗特数；湍流区域； CFD

Abstract：

Numerical model for predicting performance of plain fin was established, which incorporated characteristics of fluid flow and heat transfer. In order to precisely calculate factors f and j in turbulent region, low-Re turbulence model was adopted and the default turbulent Prandtl number value of 0.85 was replaced by turbulent Prandtl model with UDF (user-defined function) method. Numerical results of factors j and f were compared with experimental work. The average absolute relative deviations of factors j and f between numerical and experimental results are 6.72% and 6.47% respectively. The temperature at center of fin was lowest and was called T_c for convenience. The temperature difference between T_c and T_in (temperature of fluid before entering fin passage) was about 5%-18% lower than the temperature difference between up (down) plate and T_in. In order to increase overall performance of plain fin, intersections of fin and up (down) plate were periodically cut away, and the factor j was 2.76%-12.44% higher than the original one.

Keywords： plain fin； low-Re turbulence model； turbulent Prandtl number； turbulent region； CFD

Received 2015-01-04;

Corresponding Authors: 朱慧铭,E-mail:hzhu@tju.edu.cn。 Email: hzhu@tju.edu.cn

About author: 徐赛(1989-),男,硕士研究生,主要研究方向为强化传热。

引用本文:

徐赛, 朱慧铭, 喻茹.平直翅片的数值模拟及结构改进[J]. 化学工业与工程, 2017,34(1): 65-70

Xu Sai, Zhu Huiming, Yu Ru.Simulation of Plain Fin and Structural Improvement[J]. Chemcial Industry and Engineering, 2017,34(1): 65-70

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