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毕业论文网 > 毕业论文 > 理工学类 > 轮机工程 > 正文

基于FLUENT仿真分析的板翅式换热器结构的优化设计毕业论文

 2021-04-19 00:42:33  

摘 要

随着我国经济的快速发展,加上我国本身人口基数大,使得我国的能源问题十分严峻。而地球上的能源储存又是有限的,因此积极地去研究新型的节能技术,用以提高能源的使用效率变得至关重要。本文通过对板翅式全热式交换器进行改进升级,制造出一种高效率全热式交换器,最后将改进好的板式全热交换器与空调机组合,并采用流体动力仿真软件FLUENT测试不同风速下全热式交换器的换热效率和空调机的能耗情况,以达到节约能源的目的。其主要工作内容如下:

一、首先通过查阅文献分析空调换气系统,然后,通过实地调研,对各种换热器的优缺点进行分析统计,根据分析结果,选择适合于空调换气系统的板翅式全热换热器来进行结构优化。

第二、采用空气分离膜与化学纤维复合而成的新型热质交换材料对现有的全热式交换器进行改进升级,制造出一种高效率全热式交换器。这种新型的高效板翅式全热换热器,它包括翅片、换热器壳体、新风进口、排风出口、热质交换材料,上挡板和下挡板。换热器壳体上设有新风进、出口和排风进、出口。新风出口,排风进口设在换热器壳体的下部,新风进口、排风出口设在换热器壳体的上部。在新风口内设有多个第一隔板,从而将新风口设置成多个新风腔,在排风口内设有多个第二隔板,从而将排风口设置成多个排风腔,新风腔与排风腔均为矩形腔体。同时,进风口与排风口垂直布设,使新风与排风能够以交叉形式流过换热器。高效板翅式全热换热器所采用的热质交换材料是由空气分离膜与能透湿透热且具有一定强度的化学纤维复合而成。

三、对这种新型的板翅式全热换热器进行模型的建立,然后采用ICEM CFD进行网格单元划分。其次,采用流体动力仿真软件FLUENT对不同风速下全热式交换器的换热效率和空调机的能耗情况进行仿真模拟。最后,利用FLUENT内置后处理功能对结果进行分析,在FLUENT仿真结果分析的基础上对其结构不断进行优化。

四、根据FLUENT仿真结果我们得出这种新型的板翅式全热换热器排风的热回收效率受风速影响,随风速提高而逐渐下降,且下降速度慢慢减少,当新风风速为2.4m/s时,排风热回收效率可达50.8%,因此我们可知这种新型的板翅式全热换热器的热回收效率较高。在3m/s时,热回收效率仍未低于45%,由此结果我们可知该板翅式全热换热器在较高风速下依然能保持不低的热回收效率,同时也证明了本文对板翅式全热换热器的结构优化是合理的。

关键词:板翅式换热器;FLUENT仿真;换热效率;结果分析;结构优化;

Abstract

With the rapid development of China’s economy and the large population base of China’s population, the energy issue in China is very serious. As the energy storage on the earth is limited, it is of utmost importance to actively study new energy-saving technologies to improve energy efficiency. In this paper, a high-efficiency full-heat exchanger is manufactured by upgrading the plate-fin type full-heat exchanger. Finally, the improved plate full heat exchanger is combined with the air conditioner, and the fluid dynamic simulation software FLUENT is used for testing. The heat exchange efficiency of the full-heat exchanger and the energy consumption of the air conditioner at different wind speeds are used to save energy. Its main work is as follows:

Firstly, we first analyzed the air-conditioning ventilation system by consulting the literature. Then, through field research, we analyzed the statistics of the advantages and disadvantages of various heat exchangers, and based on the analysis results, we selected a plate-fin type full-heat exchange suitable for air-conditioning ventilation systems. Heater for structural optimization.

Secondly, a new type of high-efficiency full-heat exchanger is manufactured by upgrading the existing full-heat exchangers using a new type of thermal exchange material made of an air separation membrane and a chemical fiber. This new type of efficient plate-fin type full heat exchanger includes fins, heat exchanger housing, fresh air inlet, exhaust outlet, heat exchange material, upper baffle and lower baffle. The heat exchanger shell is provided with new air inlets, outlets and exhaust air inlets and outlets. The new air outlet, the exhaust inlet is located in the lower part of the heat exchanger shell, and the fresh air inlet and exhaust outlet are located in the upper part of the heat exchanger shell. A plurality of first baffles are arranged in the new tuyere so that the new tuyere is arranged into a plurality of new air chambers, and a plurality of second baffles are arranged in the air expelling vents so that the air vents are arranged into a plurality of exhaust chambers. The fresh air cavity and the exhaust cavity are rectangular cavities. At the same time, the air inlets and air outlets are laid vertically so that the fresh air and exhaust air can flow through the heat exchangers in an intersecting manner. The heat and mass exchange material used in the high-efficiency plate-fin heat exchanger is composed of an air separation membrane and a chemical fiber that is permeable to moisture and has a certain strength.

Thirdly, establish a model for this new type of plate-fin heat exchanger, and then use ICEM CFD to divide the grid cells. Secondly, the simulation software FLUENT was used to simulate the heat exchange efficiency of the full heat exchanger and the energy consumption of the air conditioner under different wind speeds. Finally, using FLUENT's built-in post-processing function to analyze the results, the structure of FLUENT is continuously optimized based on the analysis of simulation results.

At last, according to FLUENT simulation results, we conclude that the heat recovery efficiency of this new type of plate-fin heat exchanger is affected by the wind speed, gradually decreases with the increase of wind speed, and the decrease speed decreases gradually. When the new wind speed is At 2.4m/s, the exhaust heat recovery efficiency is up to 50.8%, so we know that this new type of plate-fin heat exchanger has higher heat recovery efficiency. At 3m/s, the heat recovery efficiency is still not less than 45%. As a result, we can see that the plate-fin heat exchanger can still maintain a low heat recovery efficiency at high wind speeds, and it also proves that this paper The structural optimization of the plate-fin heat exchanger is reasonable.

Key Words:plate-fin heat exchanger; FLUENT simulation; heat transfer efficiency; structural optimization;

目 录

第1章 绪论 9

1.1课题研究的背景及意义 9

1.2板翅式换热器的发展现状及研究趋势 9

1.2.1国外板翅式换热器的发展现状 9

1.2.2国内板翅式换热器的发展现状 10

1.2.3板翅式换热器的研究趋势 11

第2章 流体力学基础和数值模拟分析 11

2.1流体力学基础 11

2.1.1流体的基本性质 11

2.1.2流体运动的基本概念 13

2.1.3流体流动及换热的基本控制方程 13

2.2数值模拟简介 13

2.2.1 CFD软件概述 13

2.1.3 FLUENT简介 14

第3章 板翅式换热器结构优化设计 15

3.1引言 15

3.2板翅式换热器的特点 16

3.3板翅式换热器模型数值确定 17

3.3.1计算区域的确定 17

3.3.2模型几何尺寸和主要参数 18

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