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T Reith - One of the best experts on this subject based on the ideXlab platform.

  • novel Spacers for mass transfer enhancement in membrane separations
    Journal of Membrane Science, 2005
    Co-Authors: F Li, W Meindersma, A B De Haan, T Reith
    Abstract:

    The optimal flow pattern for mass transfer enhancement in spacer-filled channels is characterized by the coexistence of transversal and longitudinal vortices in the flow close to the channel walls and minimal cross-flow power consumption in the middle of the channel. The mass transfer enhancement of Spacers with modified filaments, twisted tapes and multi-layer structures, which were expected to generate these flow patterns, was investigated experimentally. The results indicate that the performance of Spacers with modified filaments and twisted tapes is generally worse while the performance of Spacers with multi-layer structure is generally better than that of the optimal non-woven net spacer. An optimal multi-layer spacer was designed with optimal non-woven nets in the outer layers and twisted tapes in the middle-layer. Its average Sherwood number is about 30% higher than the Sherwood number of the optimal non-woven spacer at the same cross-flow power consumption whereas the cross-flow power consumption is only about 40% of the consumption of the optimal non-woven spacer at the same Sherwood number. The Reynolds number based on the height of a spacer-filled channel varies from 40 to 500 in present study.

  • optimization of commercial net Spacers in spiral wound membrane modules
    Journal of Membrane Science, 2002
    Co-Authors: F Li, W Meindersma, A B De Haan, T Reith
    Abstract:

    CFD simulations have been used to determine mass transfer coefficients and power consumption of commercial net Spacers. The simulations show transversal and longitudinal vortices, vortex shedding and instationary flow behavior leading to the enhanced mass transfer in spacer filled-channels compared to empty channels. The results of the simulations were validated with experiments and compared with data reported in literature, showing satisfactory agreement. Furthermore, CFD simulations were used to optimize the geometry of commercial net Spacers in terms of mass transfer and power consumption. The performance of these optimized spacer geometries will be used as reference for future work on the development of new high-performance spacer shapes.

Tzyy Haur Chong - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of solid, liquid and powder forms of 3D printing techniques in membrane spacer fabrication
    Journal of Membrane Science, 2017
    Co-Authors: Wen See Tan, Jia An, Stanislaus Raditya Suwarno, Chun Kiang Chua, Anthony Gordon Fane, Tzyy Haur Chong
    Abstract:

    Feed channel Spacers in a spiral wound membrane module are net-like structures that influence the hydrodynamics of the feed channel to improve the mass transfer, thus reducing the effect of concentration polarization. Common issues associated with feed channel Spacers include the trade-off between mass transfer and pressure loss as well as their impact on membrane fouling. Prior studies mainly focused on optimizing the geometry and orientation of Spacers. 3D printing techniques have been used to fabricate novel spacer with complex geometries that were limited by conventional manufacturing methods. Nevertheless, 3D printing is not perfect, for example, not all design features can be additive manufactured with accuracy. 3D printing can also inadvertently result in different surfaces and geometry deviations of the Spacers. This study investigates different 3D printing techniques that result in spacer geometry and surface differences and their effect on membrane performance and fouling. All 3D printed Spacers by FDM, SLS and Polyjet showed better performance in terms of mass transfer at fixed power consumption and critical flux than the commercial spacer. Polyjet was found to give the most accurate representation of the intended design while FDM produced Spacers that showed the greatest deviation from the specifications. The design considerations for additive manufactured Spacers in geometric printability, model to part accuracy and surface finish are recommended. The implication of this research is that factors to be considered in spacer fabrication by 3D printing technique or other methods shall not be limited to the geometry parameter, the accuracy and surface finish associated with the fabrication methods are equally important.

  • Morphological Comparison of 3d Printed Feed Spacers for Spiral Wound Membrane Modules
    Proceedings of the 1st International Conference on Progress in Additive Manufacturing, 2014
    Co-Authors: Wen See Tan, Jia An, Chun Kiang Chua, Anthony Gordon Fane, Tzyy Haur Chong
    Abstract:

    This paper presents the preliminary work done on the fabrication of feed channel Spacers with rapid prototyping, 3D printing or additive manufacturing (AM) techniques, involving fused deposition modeling (FDM) and polyjet printing. Feed channel Spacers are mesh-like structures placed between membrane leafs in spiral wound modules (SWM) for water treatment applications. AM techniques are employed as tools to fabricate novel feed spacer with complex geometries that maximize mass transfer and minimize feed channel pressure drop and fouling across the SWM. The morphology of the AM printed spacer samples, as well as the dimensional accuracies are examined and compared in this paper.

F Li - One of the best experts on this subject based on the ideXlab platform.

  • novel Spacers for mass transfer enhancement in membrane separations
    Journal of Membrane Science, 2005
    Co-Authors: F Li, W Meindersma, A B De Haan, T Reith
    Abstract:

    The optimal flow pattern for mass transfer enhancement in spacer-filled channels is characterized by the coexistence of transversal and longitudinal vortices in the flow close to the channel walls and minimal cross-flow power consumption in the middle of the channel. The mass transfer enhancement of Spacers with modified filaments, twisted tapes and multi-layer structures, which were expected to generate these flow patterns, was investigated experimentally. The results indicate that the performance of Spacers with modified filaments and twisted tapes is generally worse while the performance of Spacers with multi-layer structure is generally better than that of the optimal non-woven net spacer. An optimal multi-layer spacer was designed with optimal non-woven nets in the outer layers and twisted tapes in the middle-layer. Its average Sherwood number is about 30% higher than the Sherwood number of the optimal non-woven spacer at the same cross-flow power consumption whereas the cross-flow power consumption is only about 40% of the consumption of the optimal non-woven spacer at the same Sherwood number. The Reynolds number based on the height of a spacer-filled channel varies from 40 to 500 in present study.

  • optimization of commercial net Spacers in spiral wound membrane modules
    Journal of Membrane Science, 2002
    Co-Authors: F Li, W Meindersma, A B De Haan, T Reith
    Abstract:

    CFD simulations have been used to determine mass transfer coefficients and power consumption of commercial net Spacers. The simulations show transversal and longitudinal vortices, vortex shedding and instationary flow behavior leading to the enhanced mass transfer in spacer filled-channels compared to empty channels. The results of the simulations were validated with experiments and compared with data reported in literature, showing satisfactory agreement. Furthermore, CFD simulations were used to optimize the geometry of commercial net Spacers in terms of mass transfer and power consumption. The performance of these optimized spacer geometries will be used as reference for future work on the development of new high-performance spacer shapes.

Wen See Tan - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of solid, liquid and powder forms of 3D printing techniques in membrane spacer fabrication
    Journal of Membrane Science, 2017
    Co-Authors: Wen See Tan, Jia An, Stanislaus Raditya Suwarno, Chun Kiang Chua, Anthony Gordon Fane, Tzyy Haur Chong
    Abstract:

    Feed channel Spacers in a spiral wound membrane module are net-like structures that influence the hydrodynamics of the feed channel to improve the mass transfer, thus reducing the effect of concentration polarization. Common issues associated with feed channel Spacers include the trade-off between mass transfer and pressure loss as well as their impact on membrane fouling. Prior studies mainly focused on optimizing the geometry and orientation of Spacers. 3D printing techniques have been used to fabricate novel spacer with complex geometries that were limited by conventional manufacturing methods. Nevertheless, 3D printing is not perfect, for example, not all design features can be additive manufactured with accuracy. 3D printing can also inadvertently result in different surfaces and geometry deviations of the Spacers. This study investigates different 3D printing techniques that result in spacer geometry and surface differences and their effect on membrane performance and fouling. All 3D printed Spacers by FDM, SLS and Polyjet showed better performance in terms of mass transfer at fixed power consumption and critical flux than the commercial spacer. Polyjet was found to give the most accurate representation of the intended design while FDM produced Spacers that showed the greatest deviation from the specifications. The design considerations for additive manufactured Spacers in geometric printability, model to part accuracy and surface finish are recommended. The implication of this research is that factors to be considered in spacer fabrication by 3D printing technique or other methods shall not be limited to the geometry parameter, the accuracy and surface finish associated with the fabrication methods are equally important.

  • Morphological Comparison of 3d Printed Feed Spacers for Spiral Wound Membrane Modules
    Proceedings of the 1st International Conference on Progress in Additive Manufacturing, 2014
    Co-Authors: Wen See Tan, Jia An, Chun Kiang Chua, Anthony Gordon Fane, Tzyy Haur Chong
    Abstract:

    This paper presents the preliminary work done on the fabrication of feed channel Spacers with rapid prototyping, 3D printing or additive manufacturing (AM) techniques, involving fused deposition modeling (FDM) and polyjet printing. Feed channel Spacers are mesh-like structures placed between membrane leafs in spiral wound modules (SWM) for water treatment applications. AM techniques are employed as tools to fabricate novel feed spacer with complex geometries that maximize mass transfer and minimize feed channel pressure drop and fouling across the SWM. The morphology of the AM printed spacer samples, as well as the dimensional accuracies are examined and compared in this paper.

W Meindersma - One of the best experts on this subject based on the ideXlab platform.

  • novel Spacers for mass transfer enhancement in membrane separations
    Journal of Membrane Science, 2005
    Co-Authors: F Li, W Meindersma, A B De Haan, T Reith
    Abstract:

    The optimal flow pattern for mass transfer enhancement in spacer-filled channels is characterized by the coexistence of transversal and longitudinal vortices in the flow close to the channel walls and minimal cross-flow power consumption in the middle of the channel. The mass transfer enhancement of Spacers with modified filaments, twisted tapes and multi-layer structures, which were expected to generate these flow patterns, was investigated experimentally. The results indicate that the performance of Spacers with modified filaments and twisted tapes is generally worse while the performance of Spacers with multi-layer structure is generally better than that of the optimal non-woven net spacer. An optimal multi-layer spacer was designed with optimal non-woven nets in the outer layers and twisted tapes in the middle-layer. Its average Sherwood number is about 30% higher than the Sherwood number of the optimal non-woven spacer at the same cross-flow power consumption whereas the cross-flow power consumption is only about 40% of the consumption of the optimal non-woven spacer at the same Sherwood number. The Reynolds number based on the height of a spacer-filled channel varies from 40 to 500 in present study.

  • optimization of commercial net Spacers in spiral wound membrane modules
    Journal of Membrane Science, 2002
    Co-Authors: F Li, W Meindersma, A B De Haan, T Reith
    Abstract:

    CFD simulations have been used to determine mass transfer coefficients and power consumption of commercial net Spacers. The simulations show transversal and longitudinal vortices, vortex shedding and instationary flow behavior leading to the enhanced mass transfer in spacer filled-channels compared to empty channels. The results of the simulations were validated with experiments and compared with data reported in literature, showing satisfactory agreement. Furthermore, CFD simulations were used to optimize the geometry of commercial net Spacers in terms of mass transfer and power consumption. The performance of these optimized spacer geometries will be used as reference for future work on the development of new high-performance spacer shapes.