论文总字数：51837字

摘 要

水和水蒸气在当今社会工业生产及科学研究当中不可或缺。由于水和水蒸汽的热力性质往往在不同的工作状况下发生显著的数值变化，且在当下，设计研究人员更多地是利用查表法与插值法进行物性参数的计算，计算完成后再手动输入进计算机或表格中进行接下来的工作，这大大增加了工作人员的工作量及其难度，也增加了数值输入错误而导致未得到想要结果的风险。本课题希望结合高度发达的计算机编程系统，将水和水蒸气热物性参数的计算依靠计算机程序来实现，进而应用于仿真模拟、课堂教学等环境中去。

本文将首先通过对IFC-67公式进行分析，给出其适用的温度、压力范围及其划分出的六个子区域的描述性数学公式，从而证明使用IFC-67公式做为程序开发基础是合理的。再通过对现有水与水蒸气热特性参数计算方法进行比较，明确本文使用计算机进行现代化编程程序开发的优势。

由于Fortran语言在数学计算领域的先进性和高级性，本文选取Fortran高级编程语言作为基础进行水蒸气热物性参数计算程序开发。程序在IFC-67公式所适用的范围之内，可实现输入例如压力、温度这两个参数进而得到其工况下的熵、焓、比体积的功能。每个子程序的算法逻辑与框图亦在本文中进行展示。程序开发完毕后，为了验证其有效性，在其编程环境下设计了两则喷管绝热流动案例进行计算，经热力学计算软件对其结果验证比对后结果正确，故证明了本程序精准度高，可应用于后续计算、设计中。

为了更好地将本程序与实际研究设计关联，本文着眼于CFD模拟仿真软件Fluent的结合。通过对喷管绝热流动案例验证二的改编，在Gambit软件中设计出一个3D渐缩喷管，并划分出70400个正六面体单元网格，设置好边界条件后带入Fluent进行仿真模拟。在Fluent中，本文设计了三种密度基、四种计算条件进行仿真模拟，对比计算数据结果，得出以下主要结论：实际气体模型在喷管中的膨胀过程不充分，内能转化为动能的效率比理想气体模型低，导致模拟前后实际气体温度、密度进出口的数据都高于理想气体，故温度、密度进出口值更贴近标准值。而实际气体模型调用的UDF函数是依据压力与密度实时关系来进行输出的，其速度进出口偏差率低于理想气体模型。

因此，高温高压下进行工质为水蒸气的仿真模拟时，将工质视为理想气体调用理想气体方程进行模拟时数据精准度略差，而使用本文开发出的Fortran程序所编写出的UDF函数既能将压力、温度、密度的函数关系联系起来，又兼顾了水蒸气作为实际气体进行模拟时物性参数的精准度，进而证明本课题中使用Fortran语言开发出的水和水蒸气热物性参数计算程序是更精准有效的。

关键词: 水蒸汽 CFD UDF Fortran

Study on Calculation Method of Thermal Physical Parameters of Water and Steam

Abstract

The thermophysical parameters of water and steam are widely used in daily research now. The quality of its values ​​largely determines the authenticity, effectiveness, and accuracy of the design and research. Because the thermal properties of water and water vapor often change significantly under different working conditions, and design researchers are more often using table look-up method and interpolation method to calculate the physical property parameters, and then manually Entering it into a computer or a table for the next work greatly increases the workload and difficulty of the staff, and also increases the risk of incorrect input of values, resulting in undesired results. This subject hopes to combine the highly developed computer programming system to realize the calculation of water and water vapor thermal properties parameters by computer program, and then apply it to the environment of simulation and classroom teaching.

This article will first analyze the IFC-67 formula and give the descriptive mathematical formulas of its applicable temperature, pressure range and its six sub-regions, thus proving that it is reasonable to use the IFC-67 formula as the basis for program development . Then by comparing the other calculation methods of the water and steam, the advantages of using a computer for the development of modern programming programs are clarified.

Due to the advanced and advanced nature of the Fortran language in the field of mathematical calculations, this article selects the Fortran high-level programming language as the basis for the development of calculation programs for the thermal properties of water vapor. The program can achieve the functions of inputting two parameters such as pressure and temperature to obtain the entropy, enthalpy and specific volume under its working conditions within the applicable range of the IFC-67 formula. The algorithm logic will be made for block diagram,and they will be shown in this article. After the program was developed, in order to verify its effectiveness, two cases of nozzle adiabatic flow were designed and calculated under its programming environment. The thermodynamic calculation’s results were verified that the program were correct. Therefore, this program proved to be highly accurate , Can be used in subsequent calculations and designs.

In order to better associate this program with actual research and design, this article focuses on the combination of CFD simulation and simulation software Fluent. Through the adaptation of the nozzle adiabatic flow case verification II, a 3D tapered nozzle was designed in Gambit software, and 70,400 regular hexahedral element grids were divided, and the boundary conditions were set and brought into Fluent for simulation. In Fluent, this paper designed four calculation conditions for simulation and compared the results of the calculation data to draw the following main conclusions: when water vapor flows under high temperature and high pressure, it will viscously rub against the wall surface, forming a layer of gradually thickening speed Boundary layer, the gradually thickening of the boundary layer results in a smaller flow area of ​​the actual gas in the actual flow field, higher energy loss, and a lower velocity. However, when the water vapor is used as an ideal gas for the simulation, the narrow velocity loss of the boundary layer is low, and the velocity import and export results are higher than the true values. It is inferred from the continuity equation that the ideal gas density import and export results will also be lower than the actual gas.

Therefore, when the steam is fluiding thought the high temperature and high pressure area, the working fluid is regarded as an ideal gas. When the ideal gas equation is called for simulation, the result will be distorted. Using the UDF function written in the Fortran program developed in this paper It can link the functional relationships of pressure, temperature and density, and also takes into account the accuracy of physical property parameters when simulating water vapor as an actual gas, and further proves the calculation program is more accurate and effective.

Key words: steam CFD UDF Fortran

目录

摘要 I

Abstract III

目录 V

第一章 绪 论 1

1.1课题研究背景及意义 1

1.2国内外发展及研究现状 1

1.2.1国外发展及研究现状 1

1.2.2国内发展及研究现状 2

1.3总结 6

第二章 程序编写基础与数学模型 7

2.1理论基础 7

2.1.1公式适用范围 7

2.1.2公式分区 7

2.2IFC公式各子区域计算公式 8

2.2.1子区域1的计算公式 8

2.2.2子区域2的计算公式 10

2.2.3子区域间边界线方程 12

2.2.4子区域6的计算公式 13

2.3本章小结 13

第三章 水蒸气热力学参数程序开发及验证 15

3.1程序设计基础 15

3.1.1水和水蒸气计算方法比较 15

3.3.2Fortran语言简介 15

3.2程序各计算功能设计框图 15

3.2.1子程序及其功能说明 15

3.2.2子程序PH的计算公式及其框图 17

3.2.3子程序PS的计算公式及其框图 20

3.2.4子程序HS的计算公式及其框图 23

3.3计算实例验证 27

3.3.1喷管绝热流动案例验证一 27

3.3.2喷管绝热流动案例验证二 27

3.4本章小结 28

第四章 CFD理论基础及UDF介绍 29

4.1引言 29

4.2CFD的计算步骤 30

4.3CFD模拟仿真软件Fluent在喷管流动中的应用 30

请支付后下载全文，论文总字数：51837字