论文总字数：30534字

摘 要

在工业生产与日常生活中，常出现大量的中低位余热资源被直接排放，这些余热能源的浪费不仅造成了环境污染，更是消耗了自然界中的其他能源，也造成了水力，风能等资源的浪费，因此对余热能源展开有效利用与回收，显得至关重要。本课题主要针对有机朗肯循环(ORC)系统进行分析，探寻ORC循环中的相关变化，而ORC技术则是一项利用低温余热的极具前景的技术。

本设计的有机工质为R245fa，热源为空气，冷源为冷却水，通过MATLAB R2019a调用REFPROP9.1对ORC循环数据进行建模，通过T-S图分析各个状态点的物性变化，并计算出各关键点的参数，研究蒸发温度，冷凝温度变化对循环系统产生的各种影响，分析这些因素出现的原因，运用Origin绘图工具使得影响表现更加直观。

最后通过MATLAB R2019a对功率100kW的ORC系统进行相关的热力计算与结构计算，汇总基本数据，根据估算传热系数设计换热器的传热面结构，确定流速，管数，管长，折流板数，折流板直径，缺口高度等主要数据，运用CAD对蒸发过程中的换热器进行画图设计，得出管子排列摆放方式，并计算出管束中心距离，通过壳体长度和压力标准求出应用壳体内径，并通过阻力公式，计算出管程部分的阻力与壳程部分的阻力，最后对壁面温度，传热面积的比值，系统阻力压降进行校核验证，判断其是否符合要求标准。

关键词：R245fa 有机朗肯循环 换热器

The design of a 200kW Organic Rankine Cycle Power Generation System with R245fa

ABSTRACT

In industrial yielding and everyday life, lost of low and middle-level waste heat resources are often directly discharged. The waste of these heat energy not only causes nature pollution, also consumes other energy sources in nature, but also causes hydropower, wind energy and other resources waste, so how effective recycle and re-use residual heat energy is very important. This subject mainly analyzes the Organic Rankine Cycle (ORC) system and explores the related changes in the ORC cycle. The ORC technology is a very promising technology that uses low-temperature waste heat.

The organic working fluid of this design is R245fa, the heat source is air, and the cold source is cooling water. The REFROP9.1 is called by MATLAB R2019a to model the ORC data, and the physical properties of each state point are analyzed by the T-S diagram, and the point parameters of the key points are calculated, discuss the various effects of evaporation temperature changes on the circulation system, and the condensation temperature changes on the circulation system, analyze the causes of these factors, and use Origin drawing tools to make the impact performance more intuitive.

Finally, throug MATLAB R2019a, the thermal calculation and structural calculation of the ORC system with a power of 100kW are carried out. The basic data is summarized and design heat transfer surface structure of heat switch according to estimated heat transfer modulus. Determine the main data such as flow rate, number of tubes, tube length, number of baffles, diameter of baffles, notch height, Then, use CAD to sketch the heat exchanger during the evaporation process, determine the tube arrangement and tube center distance, shell inner diameter, etc, calculate the tube side resistance, shell side resistance. At last, to the wall temperature, the area ratio of heat transfer, shell side pressure drop, we can check and verify whether it meets the required standards.

Keywords: R245fa Organic Rankine Cycle heat exchanger

目录

摘要 I

ABSTRACT II

第一章 绪论 1

1.1研究背景及意义 1

1.2研究现状 1

1.2.1国内研究现状 1

1.2.2国外研究现状 3

1.3研究内容 4

第二章 ORC系统性能分析 5

2.1 ORC发电原理 5

2.1.1 ORC发电原理 5

2.1.2 设计背景及条件 5

2.2 ORC循环模型的建立 6

2.2.1 ORC系统设计方法 6

2.2.2 ORC系统设计使用的软件 6

2.2.3 ORC系统热力模型的建立 7

2.3热力性能分析 10

2.3.1蒸发温度变化对系统的影响 10

2.3.2冷凝温度变化对系统的影响 11

2.4小结 12

第三章 换热器设计 13

3.1换热器的设计 13

3.1.1 原始数据、流体参数、传热量及平均温差 13

3.1.2传热面积的估算及传热结构 15

3.1.3 管程计算、壳程结构及壳程计算 18

3.1.4传热面积、壁温检验和相关阻力计算 20

3.2小结 22

第四章 总结 23

参考文献 24

附录一 ORC循环热力计算程序 27

附录二 蒸发温度5℃的热力计算 29

附录三 冷凝度 10℃的热力计算 31

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