旋转错流式膜分离过程的CFD流体动力学研究

发布时间：2018-03-26 07:22

  本文选题：旋转错流　切入点：旋转速度　出处：《膜科学与技术》2017年04期

【摘要】：在不同盘间距和转速下,利用MRF、多孔介质模型和基于k-ω湍流模型对旋转错流式膜分离过程的出水阶段和不出水"冲刷"阶段进行了流体动力学分析,揭示其内部流动规律,并与测定的结果比较,显示模拟结果与试验吻合较好.分析结果表明:在出水阶段,当盘间距每减小5mm,在60r/min时流速的峰值会减小约10%,但随着膜盘转速的增加,这种差异性逐渐减小,同时膜盘间主要流速范围沿盘径向外推移.在不出水阶段,流速的峰值随盘间距减小而增加,而转速的增加使曲线差异性减小,同时膜表面剪切力会随转速增加而增大,可增强对膜表面的冲刷,减缓膜通量的衰减;膜盘间距对剪切力的影响在低转速下较明显,但随着转速提高,曲线差异性逐渐变小,当转速达到500r/min时曲线的峰值差异已减小到约1Pa.另通过实验表明,转速和出水量的变化具有不一致性,转速大于400r/min时,出水量开始明显减小,说明设备运行时转速不宜过大.并在此基础上尝试对加入扰流板的改进设备结构进行模拟,模拟结果显示,改进结构可使膜表面的剪切力峰值增加约1.5Pa,进一步缓解膜通量的衰减.
[Abstract]:The use of MRF in different space and speed, and the porous media model and the water phase k- turbulence model of rotary cross flow membrane separation process and no water "scour" stage based on fluid dynamics analysis, reveal the internal flow law and determination results compared, show the simulation results are in agreement with experimental ones good. The analysis results show that: in the water phase, when the plate spacing for each reduced 5mm, peak velocity in 60r/min will be decreased by about 10%, but with the increasing film plate speed, the difference decreases gradually, while the main flow velocity along the membrane disc disc diameter goes outward. In the water phase, with the peak velocity the plate spacing decreases, while the speed of the increase curve difference decreases, the surface shear stress and the film will increase with increasing speed can be enhanced on membrane surface erosion, slow attenuation of membrane flux; membrane plate spacing on shear stress At low speeds is obvious, but with the speed increase, the curve difference becomes smaller, the peak difference when the speed is 500r/min curve has been reduced to about 1Pa. in the other experiment shows that the speed and the change of water is not consistent, the speed is greater than 400r/min, the water began to decrease, indicating when the equipment is running speed should not be too large. And on this basis, try to improve the equipment structure to simulate the spoiler added, the simulation results show that the improved structure can make the shear stress peak membrane surface increased by about 1.5Pa, the attenuation of membrane flux further ease.

【作者单位】： 上海海事大学海洋科学与工程学院;
【基金】：广西壮族自治区水利科技项目资助(201316)
【分类号】：TQ028.8
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本文编号：1666911