论文总字数：20122字

摘 要

闪蒸是水的一种相变过程，就是在一定温度和压力下的未饱和水，如果压力下降到某一特定温度的饱和压力之时，就会开始汽化。在化工安全领域，两相闪蒸射流是泄漏事故一种典型形式。闪蒸射流是一个剧烈的相变过程，液芯分裂成韧带并进一步破碎成液滴。剧烈的相位变化可能损坏设施。细小的液滴悬浮在空气中基于密度的不同可能会形成重气或轻气云团，最终演变成蒸汽云爆炸。闪蒸出的易燃液体会在地面积聚形成液池。由闪蒸射流衍生的灾难性事故在国内外均有发生，因此，对两相闪蒸的研究是非常有必要的。两相闪蒸射流的外部形态既直接影响了事故发展的进程，也是内在射流参数变化的具体表现，具有较大的研究价值。目前，有两种传统的方法（喷雾角（Th）和喷雾宽度（h））对近场闪蒸射流的形态进行了表征。这些方法有助于描述锥形射流，如液体射流和外部闪蒸射流。然而，当它们被用于表征内部闪蒸射流的形态时，存在两个明显的缺陷：1、无法做到无量纲化2、无法描述近场射流形态。本文提出一种新的方法来克服传统方法的缺陷，然后借此确定闪蒸射流机制。经过一系列实验后得出结论，本文提出了Y和KX^0.5的幂函数，其中X和Y分别为射流的轴向和径向，并捕获近场射流的边界。本文所提出的表征射流近场形态的新方法旨在克服传统方法的缺陷并且更加精准的测量喷雾锥角的大小，由于实验条件限制无法扩展到所有介质和参数，应该通过各种各样的实验条件在将来得到进一步的改进。

关键词：闪蒸 闪蒸射流 射流形态 闪蒸射流机制

Study on the shape characteristics of two-phase jet based on figure morphology

Abstract

Flash evaporation is a phase change process of water, that is, unsaturated water at a certain temperature and pressure. If the pressure drops to the saturation pressure of a certain temperature, it will begin to vaporize. In the field of chemical safety, two-phase flash jets are a typical form of leakage accidents. The flash jet is a violent phase change process, the liquid core splits into ligaments and is further broken into droplets. Severe phase changes can damage the facility. Small droplets suspended in the air based on the difference in density may form heavy or light gas clouds, and eventually evolve into a vapor cloud explosion. Flammable liquid flashed out will accumulate in the ground to form a liquid pool. Catastrophic accidents derived from flash jets have occurred at home and abroad. Therefore, the study of two-phase flash evaporation is very necessary. The external shape of the two-phase flash jet not only directly affects the progress of the accident, but also is a concrete manifestation of the changes in the internal jet parameters, and has great research value. At present, there are two traditional methods (spray angle (Th) and spray width (h)) to characterize the morphology of near-field flash jets. These methods help describe conical jets, such as liquid jets and external flash jets. However, when they are used to characterize the shape of internal flash jets, there are two obvious flaws: 1. The dimensionlessness cannot be achieved 2. The near-field jet shape cannot be described. This paper proposes a new method to overcome the shortcomings of traditional methods, and then to determine the flash jet mechanism. After a series of experiments, it is concluded that this paper proposes power functions of Y and KX0.5, where X and Y are the axial and radial directions of the jet, respectively, and capture the boundary of the near-field jet. The new method for characterizing the near-field morphology of the jet proposed in this paper aims to overcome the shortcomings of the traditional method and more accurately measure the size of the spray cone angle. Due to the limitations of the experimental conditions, it cannot be extended to all media and parameters. Conditions will be further improved in the future.

Key Words: Jet; form of flash ;Jet shape ;system of flash jet

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 闪蒸射流的定义 1

1.2 闪蒸射流技术的应用 1

1.3 闪蒸射流可能产生的安全事故 2

1.4 小结 2

第二章 闪蒸射流国内外研究进展 3

2.1 国内研究进展 3

2.2 国外研究现状 4

第三章 闪蒸射流机制及近场形态 7

3.1 闪蒸射流机制 7

3.2 闪蒸射流近场形态 8

3.3 一种表征闪蒸射流形态的新方法 9

第四章 图形形态学处理方法 10

4.1 闪蒸射流中图像处理应用价值 10

4.2 闪蒸射流中图像处理方法 10

4.3 近场射流形态的图像处理 11

4.3 图像处理算法的实现 12

4.4 不确定性分析 14

第五章 两相泄漏实验 14

5.1 实验设置 14

第六章 结论 17

6.1 方法的有效性分析 17

6.2 结论 19

参考文献 20

致 谢 24

请支付后下载全文，论文总字数：20122字