摘要封闭系统内的非牛顿流体流动换热问题在实际工程中是十分常见的，核反应堆就是 一种典型的封闭系统，在其安全设计时需要考虑在封闭系统内的冷却液的流动和传热问 题，防止发生泄漏或爆炸。在原油开采、食品加工等方面也都要涉及到非牛顿流体封闭 系统的换热特性研究。而幂律流体作为最典型的一种非牛顿流体，在实验模拟中常被用 于作为流体材料，本文采用的流体材料也是典型的幂律流体。79494

本文基于 FLUENT6。3 采用 CFD 方法进行仿真计算。使用 Gambit 建立二维模型，在 FLUENT 中进行模拟计算，讨论不同幂律流体物性条件（如幂律指数等）、边界条件（传 热面温差和腔体长宽比例）以及腔体内置不同钝体时，封闭系统内流体的传热特性。

模拟结果显示随着幂律指数的升高，自然对流会有所下降；而随着换热壁面温差的 增大，流体的换热强度会明显加强；添加适当体积、形状的的钝体会会加强流体的自然 对流强度。

毕业论文关键词 封闭系统 幂律流体 自然对流换热

毕 业 设 计 说 明 书 外 文 摘 要

Title Heat Transfer Characteristics of Power-Law Fluid in a Closed System

Abstract  Non Newtonian fluid flow and heat transfer in closed system is very common in practical engineering。Nuclear reactor is a typical closed system, in which the safety design needs to consider the cooling fluid flow and heat transfer in the closed system to prevent leakage or explosion。In crude oil production, food processing and so on are also related to it。As one of the most typical non Newtonian fluids, the power law fluid is often used in the experimental simulation as a fluid material。

This paper uses CFD method to simulate the simulation。The heat transfer characteristics of fluid in closed systems are discussed in terms of different power law fluid physical properties (such as power law exponent), boundary conditions , and different blunt bodies in the cavity。

Simulation results show that with the increase of the power-law index, the natural convection will decline; and with the increased heat transfer of hot wall surface temperature, fluid heat transfer intensity will significantly strengthen; adding appropriate volume and shape the dull experience will strengthen the natural convection in a fluid of strength。

Keywords  closed system    power-law fluid  Natural convection

本科毕业设计说明书 Ⅰ

目 次

1 绪论 1

1。1 研究背景及意义 1

1。2 国内外研究现状 1

1。3 本文的主要工作 2

2 相关理论简介及算例验证 4

2。1 幂律流体 4

2。2 自然对流换热模型 5

2。 3 FLUENT 软件介绍 7

2。4 相关无量纲数 8

2。5 算例验证 8

2。6