管道焊口泄漏氨气扩散特性分析

Analysis of the Diffusion Characteristics of Ammonia Leakage at Pipe Welds

针对氨制冷车间管道焊口易发生氨气泄漏的问题,研究了制冷压缩机和冷凝器之间管道焊口位置不同裂口方向对氨气泄漏扩散特性的影响,考虑了管道转弯处焊口裂口方向分别为竖直向上﹑竖直向下﹑水平向左和水平向右时氨气的扩散规律。采用CFD数值模拟方法,分析了四种焊口裂口方向下氨气泄漏扩散的空间浓度分布规律以及速度流场的分布情况。结果表明,水平向左泄漏60 s后,易燃易爆区占正常活动范围的百分比远高于其它3种泄漏方式,对车间的安全威胁最大;竖直向下泄漏60 s后,易燃易爆区域占正常活动范围面积的47.3%,威胁最小。

View ofammonia leakage problem in pipe- line welding joints of ammonia refrigeration work- shops, the influence of different crack direction on the diffusion characteristics of ammonia leakage be- tween the refrigeration compressor and the condenser was studied. Direction of cracks at the turning of the pipeline was taken into account, includingvertically upwards, vertical downwards, horizontally leftwards, and horizontally rightwards, respectively. Using the CFD numerical simulation method, the spatial con- eentration distribution of ammonia and the distribution of the velocity flow field in the four welding seams were analyzed. The results showed that after 60s the pereentage of flammable and explosive alias occup- ying the normal activity range was the highest for hor- izontally leftwards leakage, which posed the greatest safety threat to the workshop. The percentage was the lowest for vertically downwards leakage, which was only 47.3 %. The results of this study provided refer- ence and guidance for the handling of ammonia leakage accident in ammonia refrigeration workshops.