不同特征波纹管内流动特性分析

Analysis of flow characteristics in bellows with different characteristics

为探究不同特征波纹管内部流场的分布特性,基于ANSYS CFX软件,采用进口质量流量和自由出流的数值计算条件,通过对k-ε湍流模型的数值模拟,揭示了不同弯度、波节数和大小的波纹管内部流动特性和压力场分布规律,计算了相应工况下的水头损失。结果表明:(1)波纹管的弯度、波节数和大小都对其内部流场和产生的水头损失有较大影响;(2)不同弯度波纹管内部流体域的静压和流速分布趋势整体相同,从进口至出口,管内流体的静压和流速逐渐减小,随着弯度增加,进口端流体的静压逐渐增大,出口端流体的静压逐渐减小,不同弯度波纹管波节边缘流体流速都较小,中间部位流体的流速较大;(3)波纹管弯度为180°时,随着波节数的增加,管内流体域静压的变化趋势整体相同,平均最大流速呈递增趋势;(4)波纹管弯度为180°且波节数为25时,随着波纹管整体逐渐缩小,管内流体静压与流速迅速增大,X-Y截面流体静压与流速变化趋势整体不变;(5)波纹管内流场产生的水头损失与弯度和波节数呈正相关,与大小呈负相关。为波纹管的优化设计和改进以及安装使用提供参考与合理建议。

As a kind of pipe connection device,bellows are widely used in the transportation and flow control of liquid,gas and other media in various fields.In order to explore the distribution characteristics of the flow field inside the bellows with different characteristics,the numerical calculation conditions of the inlet mass flow rate(5.83 kg/s)and the free flow were adopted,and the turbulent kinetic energy k and turbulent dissipation rateεwere numerically simulated based on ANSYS CFX.The flow characteristics and pressure field distribution of bellows with different curvature,nodule number and size were revealed,and the head loss under corresponding working conditions was calculated.The results showed that:(1)the curvature,nodal number and size of the bellows had great influence on the internal flow field and the resulting head loss;(2)The static pressure and flow velocity distribution trend of the fluid domain inside the bellows with different bending degrees were the same as a whole.From the inlet to the outlet,the static pressure and flow velocity of the fluid inside the bellows gradually decreased.With the increase of curvature,the static pressure of fluid at the inlet end gradually increased,and the static pressure of fluid at the outlet end gradually decreased.The flow velocity of fluid at the edge of the corrugated pipe with different curvature was small,while the flow velocity of fluid at the middle part was large,and gradually decreased to both sides.(3)When the bend of the bellows was 180°,with the increase of the number of nodes,the change trend of static pressure in the fluid domain inside the bellows was the same as a whole,and the average maximum velocity in the bellows showed an increasing trend;(4)When the bend of the bellows was 180°and the number of nodes was 25,the static pressure and flow velocity of the fluid in the bellows gradually increased with the gradual reduction of the overall bellows,and the static pressure and flow velocity of the fluid in the X-Y section remained unchanged as a whole;(5)The head loss generated by the flow field in the bellows was positively correlated with the curvature of the bellows and the number of nodes,and negatively correlated with the size.The results of this study can provide reference for the optimization design and improvement of bellows,and provide reasonable suggestions in the installation and use of bellows.