Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control
In this paper, we study the parameters that affect the generation of droplets in a microfluidic flow-focusing junction. Droplets are evaluated based on the size and frequency of generation. Droplet size control is essential for microfluidic lab-on-a-chip applications in biology, chemistry, and medic...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-05-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/12/6/590 |
| _version_ | 1797533252283531264 |
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| author | Ali M. Ibrahim Jose I. Padovani Roger T. Howe Yasser H. Anis |
| author_facet | Ali M. Ibrahim Jose I. Padovani Roger T. Howe Yasser H. Anis |
| author_sort | Ali M. Ibrahim |
| collection | DOAJ |
| description | In this paper, we study the parameters that affect the generation of droplets in a microfluidic flow-focusing junction. Droplets are evaluated based on the size and frequency of generation. Droplet size control is essential for microfluidic lab-on-a-chip applications in biology, chemistry, and medicine. We developed a three-dimensional numerical model that can emulate the performance of the physical system. A numerical model can help design droplet-generation chips with new junction geometries, different dispersed and continuous phase types, and different flow rates. Our model uses a conservative level-set method (LSM) to track the interface between two immiscible fluids using a fixed mesh. Water was used for the dispersed phase and mineral oil for the continuous phase. The effects of the continuous-to-dispersed flow rate ratio (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>Q</mi><mi>o</mi></msub><mo>/</mo><msub><mi>Q</mi><mi>w</mi></msub></mrow></semantics></math></inline-formula>) and the surfactant concentration on the droplet generation were studied both using the numerical model and experimentally. The numerical model was found to render results that are in good agreement with the experimental ones, which validates the LSM model. The validated numerical model was used to study the time effect of changing <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>Q</mi><mi>o</mi></msub><mo>/</mo><msub><mi>Q</mi><mi>w</mi></msub></mrow></semantics></math></inline-formula> on the generated droplet size. Properly timing when the flow rates are changed enables control over the size of the next generated droplet, which is useful for single-droplet size modulation applications. |
| first_indexed | 2024-03-10T11:11:54Z |
| format | Article |
| id | doaj.art-0e77f90c8e444231801b2ef9ca0110b2 |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-03-10T11:11:54Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-0e77f90c8e444231801b2ef9ca0110b22023-11-21T20:42:36ZengMDPI AGMicromachines2072-666X2021-05-0112659010.3390/mi12060590Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size ControlAli M. Ibrahim0Jose I. Padovani1Roger T. Howe2Yasser H. Anis3Mechanical Design and Production Department, Faculty of Engineering, Cairo University, Giza 12613, EgyptDepartment of Electrical Engineering, Stanford University, Stanford, CA 94305, USADepartment of Electrical Engineering, Stanford University, Stanford, CA 94305, USAMechanical Design and Production Department, Faculty of Engineering, Cairo University, Giza 12613, EgyptIn this paper, we study the parameters that affect the generation of droplets in a microfluidic flow-focusing junction. Droplets are evaluated based on the size and frequency of generation. Droplet size control is essential for microfluidic lab-on-a-chip applications in biology, chemistry, and medicine. We developed a three-dimensional numerical model that can emulate the performance of the physical system. A numerical model can help design droplet-generation chips with new junction geometries, different dispersed and continuous phase types, and different flow rates. Our model uses a conservative level-set method (LSM) to track the interface between two immiscible fluids using a fixed mesh. Water was used for the dispersed phase and mineral oil for the continuous phase. The effects of the continuous-to-dispersed flow rate ratio (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>Q</mi><mi>o</mi></msub><mo>/</mo><msub><mi>Q</mi><mi>w</mi></msub></mrow></semantics></math></inline-formula>) and the surfactant concentration on the droplet generation were studied both using the numerical model and experimentally. The numerical model was found to render results that are in good agreement with the experimental ones, which validates the LSM model. The validated numerical model was used to study the time effect of changing <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>Q</mi><mi>o</mi></msub><mo>/</mo><msub><mi>Q</mi><mi>w</mi></msub></mrow></semantics></math></inline-formula> on the generated droplet size. Properly timing when the flow rates are changed enables control over the size of the next generated droplet, which is useful for single-droplet size modulation applications.https://www.mdpi.com/2072-666X/12/6/590microfluidicsdroplet generationdroplet modulationemulsions |
| spellingShingle | Ali M. Ibrahim Jose I. Padovani Roger T. Howe Yasser H. Anis Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control Micromachines microfluidics droplet generation droplet modulation emulsions |
| title | Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control |
| title_full | Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control |
| title_fullStr | Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control |
| title_full_unstemmed | Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control |
| title_short | Modeling of Droplet Generation in a Microfluidic Flow-Focusing Junction for Droplet Size Control |
| title_sort | modeling of droplet generation in a microfluidic flow focusing junction for droplet size control |
| topic | microfluidics droplet generation droplet modulation emulsions |
| url | https://www.mdpi.com/2072-666X/12/6/590 |
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