CFD simulation of baffles arrangement for gelatin-water ultrafiltration in rectangular channel

Formation of concentration boundary layer causes permeate flux decline in membrane processes. Baffles arrangement in different ways in the feed flow channel is an industrial method to create turbulence in order to decrease boundary layer thickness and increase permeation flux. In this study, an independent model of time step and mesh size is produced and validated against simple channel's experimental data. Six different arrangements of baffles designed in a rectangular channel are investigated. Turbulent kinetic energy, dissipation rate and intensity as well as the shear rate and total pressure on the membrane surface are reported. Permeate flow versus time is compared in six baffle arrangements as well as a simple channel without any baffles. Effectiveness is assessed based on steady-state flux. According to the model results, permeate flux in the simple channel is 4.09 × 10 −3 m 3/m 2s. Inclusion of different arrangements of baffles increases permeate flux from 4.60 × 10 −3 m 3/m 2s for the symmetrical wall baffling as the worst arrangement to 4.83 × 10 −3 m 3/m 2s for central baffling as the best one, demonstrating 12.5% to 18% increase in throughput as compared to the simple channel. Central baffling is thus regarded as the best baffle arrangement in a rectangular channel and therefore recommended. ► CFD technique is used for modeling Ultrafiltration process. ► Turbulent flow for 6 different baffle arrangements is studied. ► Different baffle arrangements result in different operational parameters. ► Different arrangement of baffles leads to 12% to 18% flux increment. ► Central arrangement of baffles is the best choice for a rectangular channel.