Slug and bubble flows in a flat sheet ultrafiltration module: Experiments and numerical simulation. (May 2017)

• Record Type: Journal Article
• Authors: Javid, Seyyed Morteza; Passandideh-Fard, Mohammad; Faezian, Ali; Goharimanesh, Masoud
• Is Part Of: International journal of multiphase flow. Volume 91(2017)
• Page Start: 39
• Page End: 50
• Publication Date: 2017-05
• Subjects: Gas bubbling -- Image processing -- VOF technique -- Membrane fouling -- Ultrafiltration; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2016.12.006
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: The size and distribution of bubbles in flow are analyzed based on image processing techniques. Successful 3D simulation of two phase flow patterns in a flat sheet module. The enhanced shear stress is due to two factors: velocity gradient of liquid near the bubbles and induced vorticity. The slug flow induces considerably larger shear stress than bubble flow. Abstract: In this paper, the effect of gas bubbling including slug and bubble flows on enhancing shear force in an ultrafiltration (UF) process in a flat sheet module is investigated experimentally by image processing and numerically using the OpenFOAM software. In order to study characteristics of bubbles in the slug and bubble flows, the flat sheet module is analyzed by a video system facilitated with a high speed camera. The experimental results show that the average diameter of the slug flow is much larger than that of the bubble flow. The permeate flux for the slug and bubble flows is increased by 78% and 30%, respectively, compared to the case with no gas bubbling. The numerical results are shown to be in good agreement with those of the measurements both qualitatively and quantitatively. The results of simulations also demonstrate that although both flow patterns increase the shear stress by increasing the velocity gradient and/or vorticity, the shear stress induced by the slug flow is considerably larger. Therefore, the slug flow with a higher induced shear stress is more effective on the enhancement of the permeate flux in a UF process.