虹吸管道内流场数值模拟研究及分析

Study on numerical simulation of the inner flow-field in different siphon pipelines

以虹吸式坐便器产品中的虹吸管道为研究对象,应用FLUENT软件对虹吸管道冲水过程中的气液两相流进行了三维数值模拟,研究了不同虹吸管道结构对虹吸性能的影响。通过改变管道结构参数(阻水段倾斜角度和爬坡段长度),分别对管道内流场进行对比分析,并依据数值模拟结果提出了虹吸管道结构优化设计的建议。模拟结果表明,虹吸管道结构直接影响虹吸性能,在管道内流场中,管顶驼峰处会产生明显的负压,影响虹吸起始时间;管道出口处均产生正压,且该处气液两相变化变得剧烈;适当缩短爬坡段长度,有利于延长虹吸持续时间;适当增加阻水段倾斜角度,有利于维持虹吸稳定。

In this paper,three different siphon pipelines were imported to the CFD software FLUENT with the gas-liquid two-phase flow field to simulate the flush process and study how the siphon pipeline structures affected the siphon performance.By changing some design parameters of the pipeline structures,including the inclined angle of resistant section and the length of upward section,numerical simulation results were analyzed and some valuable guidelines for optimizing the siphon pipeline structures was proposed.The simulation results indicated that the tip pipelines have an obvious negative pressure in the three types of siphon pipelines which is important to start the siphon phenomena.A positive pressure is generated at the outlet of the pipelines,accompanied with violent gas and liquid phase changes.Properly shortening the length of the upward section may prolong the duration of siphon.Through increase of the inclined angle of resistant section,the stability of the siphon would be more stable.