鼓泡式鱼类清洗机管路湍流数值模拟与优化

Numerical simulation and optimization of piping turbulence in bubbling fish cleaner

采用Fluent软件对鼓泡管路中的分流管内部流场进行数值模拟,选用标准k-ε湍流模型模拟分流管上每个喷气口气体的流速分布图,当分流管长为40cm时,每个喷气口气体的流速相近,产生的气泡均匀、可控。通过对分流管上的喷气孔径、孔距等相关参数进行数值模拟,使用Mixture多相流模型、扩展的标准k-ε湍流模型模拟不同气流速度对气体体积分数、湍流动能、湍流耗散率的影响。结果表明:气流流速与气体体积分数、湍流动能、湍流耗散率具有正相关性,当鼓泡管路中参考气流速度8m/s、喷气孔径6mm、喷气孔径间距70mm时,湍流动能转化比最高(67.7%)。验证实验表明:清洗时间、气流流量、清洗量对鲫鱼表面和腹腔的清洗效果影响显著,当清洗时间170s、气流流量145L/min、清洗量1.5kg时,清洗效果达92分。

First,Fluent software was used to numerically simulate the internal flow field of the shunt tube in the bubbling line,and standard k-εturbulence model was applied to simulate the velocity profile of each vent gas on the manifold.The results showed that 40 cm was the opportune length of the shunt tube to obtain the similar flow rate of each gas jet,and the uniform and controllable bubbles.Then,the Mixture multiphase flow model and the extended standard k-εturbulence model were used to simulate of the jet aperture and the hole spacing on the shunt tube.The results showed that the gas flow rate was positively related to the turbulence kinetic energy,gas volume fraction and turbulent dissipation rate.The highest turbulent flow energy conversion.ratio(67.7%)was harvested when the jet aperture was 6 mm and the hole spacing was 70 mm,on the condition of 8 m/s as the reference airflow velocity in the bubbling pipeline.The cleaning results displayed the significant effects of these factors on the cleaning effect of the surface and enterocoelia of crucian.When the cleaning time was 170 s,the air flow rate was 145 L/min,and the cleaning amount was 1.5 kg,the cleaning efficiency was as high as 92.