氨制冷压缩机低压管道泄漏冷媒扩散特性研究

田志强¹，门海东¹，廖晓玲²，王  迪³，郭  曦³，刘延雷²，赵哲明²*

（1.上海和中合检测技术有限公司，上海，201600；2.杭州市特种设备检测研究院，浙江 杭州，310051；3.东北石油大学土木建筑工程学院，黑龙江 大庆，163318）

摘  要： 针对氨制冷压缩机低压吸气管道在长期运行中存在疲劳强度下降的问题，容易导致氨气泄漏。考虑低压管道泄漏方向分别为竖直向上、水平迎风和水平背风，采用Fluent进行小孔持续泄漏模拟计算，研究了某制冷机房非开放空间内气流速度分布对氨气扩散的影响。结果表明：由于低压管道初始泄漏速度低，喷射阶段持续时间短，在受限空间内的涡流扰动作用下，氨气沿不同方向泄漏时射流方向均发生偏转，扩散区域集中在泄漏源的上风侧；水平迎风方向泄漏时，氨气在扩散区域浓度相对于其他两种情形较高，并且在上风侧越靠近泄漏源，氨气堆积越高；在机房日常工作空间范围内，水平背风方向泄漏时的易燃易爆区域占比为76.96%，稍高于其他两种泄漏情形。研究结论为合理有效地进行氨制冷压缩机低压吸气管道无损检测及运行维护提供根据。

关键词：压力管道；氨气；低压；泄漏方向；扩散特性

中图分类号：TQ053.6          文献标识码：A   

Refrigerant diffusion characteristics of low-pressure pipe leakage in ammonia refrigeration compressor

Tian Zhiqiang1, Men Haidong1, Liao Xiaoling2, Wang Di3, Guo Xi3, Liu Yanlei2*

1. Shanghai Hezhonghe Testing Technology Co., Ltd, Shang Hai, 201600; 2. Hangzhou Special Equipment Inspection and Research Institute, Hangzhou Zhejiang, 310051；3. Northeast Petroleum university, school of civil engineering and architecture, Daqing Heilongjiang, 163318

Abstract: For the low-pressure suck pipe of ammonia refrigeration compressor, there is a problem of fatigue strength decline in long-running process，which can easily lead to ammonia leakage. The leakage direction of low-pressure suck pipe are vertical upward, horizontal upwind and horizontal leeward respectively, micro pore leakage characteristic is simulated by using Fluent, the relationship between the velocity distribution of the airflow field in the confined space and the diffusion concentration distribution of ammonia in different leakage directions is analyzed. Analytical results show that the low initial leakage velocity of the low-pressure pipeline, the duration of the injection stage is short. Under the influence of the vortex disturbance in the confined space, the direction of the jet is deflected when the ammonia leaks in different directions, and the diffusion region is mainly located on the windward side of the leakage source; When the ammonia leaked along the horizontal upwind direction, the concentration of ammonia in the diffusion region was higher than the other two cases, and in the upwind region, the closer to the leakage source, the higher the ammonia accumulation; Within the spatial scope of the daily working of the machine room, the proportion of flammable and explosive areas is 76.96% when the ammonia leaked along the horizontal leeward direction, slightly higher than the other two kinds of leakage situation. The research results provide the basis for the nondestructive testing and operation maintenance of low-pressure suck pipe of ammonia refrigeration compressor.

Key words: pressure piping; ammonia; low-pressure; leakage direction; diffusion characteristics

0  引言

氨制冷压缩机低压排气口管道连接处由于腐蚀穿孔，机械振动导致紧固件松弛和垫片失效，以及人为操作不当等不可预见因素，均有可能造成氨制冷剂泄漏[1-2]。冷库氨泄漏事故造成的严重后果将给生命财产带来巨大的损害[3]。

计算流体力学（CFD）方法适于模拟复杂湍流流动的泄漏污染物扩散过程[4-8]。孙恩吉[9]基于Realizable k-ε方程对氨气泄漏进行有限元数值模拟，分析了不同泄漏位置、不同排风条件下氨气的运移规律。Tan[10]等利用Fluent软件对某食品厂冷库氨泄漏扩散进行数值模拟研究。研究了不同泄漏速度、泄漏点高度、风速等初始条件下，氨气扩散浓度分布规律。张俊飞[11]等基于Fluent软件对于氨气储罐的泄漏进行模拟，研究在不同风速、不同风向以及设置障碍物下对氨气扩散的影响。黄金磊[12]等基于高斯烟羽数学模型，利用FDS模拟研究氨泄漏扩散浓度随变化规律，氨气浓度水平方向分布呈近似蒲扇型，风力有利于氨的扩散；同时得到致死区、重伤区以及致伤区的扩散距离。然而在受限空间制冷机房内对于压缩机低压吸气管道冷媒在不同泄漏方向上对其扩散特性的研究较少。

本文将以某氨制冷机房为研究对象，考虑制冷机房内压缩机低压吸气管道泄漏方向分别为竖直向上、水平迎风和水平背风，选择RNG k-ε方程为湍流模型，采用Fluent软件进行小孔持续泄漏模拟计算，通过对含送风口的制冷机房受限空间流场速度分析，总结气态氨冷媒不同泄漏方向的扩散规律，为准确预测氨气泄漏危险区域提供依据。

1  模型的建立

1.1   物理模型

如图1所示，建立某制冷机房泄漏源所在剖面物理模型，分析氨气在受限空间内扩散特性及浓度分布规律。制冷机房尺寸为20m×6m，送风口与出风口直径均为1m；三台螺杆压缩机尺寸为1m×1m，横向排列间距为1.5m；低压循环桶直径为1.5m，高2.1m；排液桶尺寸为3m×1.5m。泄漏源位于二号压缩机，分别设置垂直向上、水平迎风与水平背风三种泄漏方向。

 氨制冷压缩机低压管道泄漏冷媒扩散特性研究.pdf