Effect Of Channel Configuration On The Filtration Performance Of Tubular Ceramic Membranes

Ceramic membranes,as filter membranes,have several advantages such as high temperature resistance,acid and alkali resistance,corrosion resistance,high mechanical strength,and small average pore size.Therefore,they have a broad development prospect in the field of water treatment,showing great potential in industrial wastewater treatment,drug purification,drinking water treatment,food processing,and other fields.In this thesis,the research focuses on the tubular ceramic membrane and conducts filtration simulation with different channel configurations by utilizing computational fluid dynamics technology.The study analyzes the distribution of pressure and velocity inside the channel as well as the permeability characteristics of each channel to investigate the influence of channel configurations on the filtration performance of tubular membrane.The three channel configurations are then summarized,and the optimal application conditions are determined by analyzing the velocity and pressure of the internal flow field.This study simulates the cross-flow filtration of pure water through a standard circular channel ceramic membrane using Fluent simulation software.A porous media model is employed to calculate the flow field distribution inside the ceramic membrane.The results indicate that the permeate flux of the ceramic membrane significantly increases with increasing inlet pressure.Furthermore,the permeate flux in the outer channels is much higher than that in the inner channels,and the pressure drop rate is faster.Studying the outlet pressure reveals that it can effectively enhance the alongchannel pressure and increase the effective filtration area of the ceramic membrane.Experimental results using circular channels of different diameters demonstrate that the permeate flux increases significantly with increasing diameter.However,the increase in diameter also leads to a more severe mutual interference between channels on the same layer.Therefore,a three-channel model is established to experimentally investigate the mutual interference between channels.The experiments reveal that there is a noticeable interaction between channels when the channel spacing is less than a specific value,and this value is found to be related to the average pore size of the ceramic membrane.Fan-shaped channels have higher permeability flux than circular channels.Filtration experiments were conducted by setting different inlet pressures,and the results showed a significant increase in permeate flux with increasing inlet pressure.However,the phenomenon of imbalanced permeate flux between the inner and outer channels still persisted.The differences in permeate flux among different permeation surfaces in the outer fan-shaped channels during operation were analyzed,and the reasons for these differences were identified.It was also observed that filtration primarily occurred in the front half of the ceramic membrane,while little to no filtration occurred in the latter half.The analysis attributed this to the high permeation rate in the outer fan-shaped channels and the rapid decrease in pressure drop along the channel.Once the internal pressure in the channel fell below the filtration pressure,filtration no longer occurred in the ceramic membrane.Finally,by varying the outlet pressure for filtration simulation,the influence of outlet pressure on the flow field inside the fanshaped channels was studied.Compared to circular and fan-shaped channels,square channel structures have a higher packing density and a larger membrane area,making them a novel ceramic membrane channel structure.This study simulated cross-flow filtration of square channel ceramic membranes and investigated the flow field inside the channel structure during the filtration process.By monitoring the permeation rate of each permeation surface in the square channels,the reasons for the imbalance in permeation rates between the inner and outer layers were analyzed.Unlike circular and fan-shaped channels,the filtration performance of square channels is evenly distributed,and they require less pressure compared to other channel configurations.