论文总字数：25999字

摘 要

水平管降膜蒸发器因其具有蒸发效率高，传热温差小，以及对介质发泡、结焦不敏感等优点，被广泛应用于热敏性，易发泡，含盐量较高物料的蒸发浓缩。作为蒸发器最重要的组成部分，液体分布器及其结构参数对蒸发性能、布水均匀度具有重要影响。如何选择并设计合适的液体分布器成为水平管降膜蒸发器配水系统结构优化的重点。本课题采用流体有限元数值分析方法，对水平管降膜蒸发器配水系统的主要结构和液体分布器布水均匀性进行了探讨和分析，其主要研究工作如下：

1. 针对常见的单相滴淋排管式液体分布器长距离布水均匀度降低的局限性，提出采用主支管式形式建立水平管降膜蒸发器液体分布器的基本构想。确定垂直主管中间进水，多层分流的物料进入方式，以及利用布液管末端连接件进行单元组合模块化安装的装配方式。
2. 依据液体分布器的实际操作环境，确定了涉及布水均匀度的布液管相关结构（开孔间距、管径、孔径等）取值范围。
3. 采用有限元数值分析方法讨论布液管不同结构参数对穿孔流量偏差η和布水不均匀度M_f的影响。同时，以穿孔流量偏差作为布水均匀度指标，探讨了布液管管径和开孔间距对满足布水均匀度要求的最大管长值L的影响。

关键词：水平管降膜蒸发器 液体分布器 有限元分析

Structure of Evaporator Perforated Water Distribution Device and Its Optimization

Abstract

Because of its high evaporation efficiency, low heat transfer temperature difference, and insensitivity to dielectric foaming and coking, horizontal tube falling film evaporators are widely used for evaporation of heat-sensitive, easily foaming, and salty materials. As the most important part of the evaporator, the liquid distributor and its structural parameters have important effects on evaporation performance and water distribution uniformity. How to select and design the suitable liquid distributor becomes the key point of structural optimization of horizontal pipe falling film evaporator water distribution system. This project uses fluid finite element numerical analysis method to discuss and analyze the main structural state of the horizontal tube falling film evaporator water distribution system and the distribution uniformity of the liquid distributor. The main research work is as follows:

1. Based on the limitations of the common single-phase dripping-leaf pipe-type liquid distributors to reduce the uniformity of long-distance water distribution, the basic idea of establishing a horizontal pipe falling film evaporator liquid distributor using a main branch pipe type is proposed. Determine the way of entering the water in the vertical main pipe, how to enter the material for multiple layers of diversion, and how to use the end fittings of the liquid pipe to perform assembly and modular installation.
2. According to the actual operating environment of the liquid distributor, the relevant structure (opening spacing, diameter, aperture, etc.) of the liquid distribution pipe involved in the water distribution uniformity was determined.
3. The finite element numerical analysis method is used to discuss the effect of different structural parameters of the liquid pipe on the perforation flow deviation η and the distribution unevenness M_f. At the same time, taking the deviation of perforation flow as the index of water distribution uniformity, the influence of pipe diameter and hole spacing on the maximum pipe length L that meets the water distribution uniformity requirements was discussed.

Keywords:Horizontal tube falling film evaporator; Liquid distributor; Finite element analysis

目 录

摘 要 I

Abstract II

第1章 绪论 1

1.1 研究背景和课题来源 1

1.2 液体分布器的研究现状 2

1.2.1 液体分布器的分类 2

1.2.2 液体分布器的国内外研究现状 3

1.3 课题主要内容 5

第2章 水平管蒸发器布水装置结构设计 7

2.1 水平管降膜蒸发器布水装置的设计 7

2.1.1 液体分布器的设计要求和方法 7

2.1.2液体分布器均布条件 8

2.2 液体分布器结构的优化 9

2.2.1布液管排列形式 9

2.2.2物料进入方式 10

2.2.3布液管连接结构 10

2.2.4整体结构安装 10

2.2.5其他部分的设计 11

2.3 液体分布器基本参数 13

2.3.1开孔间距 13

2.3.2管径 14

2.3.3孔径 14

2.3.4管长 15

第3章 布水管布水均匀性的有限元分析 16

3.1 单根布液管的数值模拟 16

3.1.1 理论模型的建立和假设 16

3.1.2 布水管网格划分及边界条件 17

3.1.3 物性参数 18

3.1.4 模拟结果与分析 18

3.2 布液管管径对布水管管长的影响 21

3.3 布液管开孔间距对布液管管长的影响 24

第4章 结论与展望 29

4.1 结论 29

4.2 展望 29

参考文献 30

致谢 32

第1章 绪 论

请支付后下载全文，论文总字数：25999字