Formation of bubbles and foams in gelatine solutions within a vertical glass tube
TL;DR: In this paper, air and gelatine solutions were mixed in a microfluidic device to produce steady flows of microbubbles by controlling liquid and gas volumetric flow rates.
About: This article is published in Food Hydrocolloids.The article was published on 2008-06-01. It has received 31 citations till now. The article focuses on the topics: Capillary action & Volumetric flow rate.
Citations
More filters
TL;DR: In this article, the authors introduce the use of dimensionless numbers to model the physical effects at the micro-fluidic scale, and present different types of geometries to generate multi-phase flows in micro-channels, techniques and materials to construct the microfluidics, as well as methods used to modify surface properties of channels.
Abstract: The design of novel food micro-structures aimed at the quality, health and pleasure markets will probably require unit operations where the scale of the forming device is closer to the size of the structural elements (i.e., 1–100 μm). One emerging possibility is microfluidics or devices that employ small amounts of fluids (10−6 to 10−9 l) flowing in channels where at least one dimension is less than 1 mm. However, under these conditions, the predominant effects are not necessarily those present in conventional macroscopic unit operations. Dominant physical effects at the microfluidic scale are introduced through the use of dimensionless numbers. Different types of geometries to generate multi-phase flows in micro-channels, techniques and materials to construct the micro-devices, principally soft lithography and laser ablation, as well as methods used to modify surface properties of channels, are reviewed. The operation of micro-devices, the role of flow regimes, rheological behaviour of fluids in micro-channels and of transient time is discussed. Finally, systems developed to generate emulsions and foams, fluid mixing and dispersion, and future applications of these devices in food processing and food analysis are presented.
124 citations
TL;DR: In this article, the effects of the confinement of microchannels and the fluid flow on bubble formation and breakup dynamics are highlighted, and the key issues for the scaling-up of bubble generation in microfluidic devices are demonstrated.
118 citations
TL;DR: Aerated gels contain both bubbles and entrapped water, thus offering ample versatility in product development as mentioned in this paper, and they may find applications in reducing the caloric density of foods and inducing satiety, as carriers of flavors and nutrients.
Abstract: Aerated gels contain both bubbles and entrapped water, thus offering ample versatility in product development. Dispersed air (or other gases) provides an additional phase within the gel that may accommodate new textural and functional demands. Many food polymers form gels and their target properties may be enhanced by combining materials (mixed polymer gels) or introducing a finely dispersed fat phase (emulsion gels). Traditional methods to generate bubbles in foods as well as non-conventional technologies (membrane processes, microfluidics, etc.) are revised and their potential applications in producing aerated gels are discussed. Aerated gels may find applications in reducing the caloric density of foods and inducing satiety, as carriers of flavors and nutrients, and in novel gastronomic structures.
110 citations
TL;DR: A greater understanding is needed of the interaction between cation-polysaccharide-water, taking into account [Alg] and [CaCl2] to predict the mechanical behavior of fibers.
86 citations
TL;DR: In this article, the formation of slug bubbles in flow-focusing microfluidic devices using a high-speed digital camera and a micro particle image velocimetry (μ-PIV) system was investigated.
Abstract: The present study aims at scaling the formation of slug bubbles in flow-focusing microfluidic devices using a high-speed digital camera and a micro particle image velocimetry (μ-PIV) system. Experiments were conducted in two different polymethyl methacrylate square microchannels of respectively 600 × 600 and 400 × 400 μm. N2 bubbles were generated in glycerol–water mixtures with several concentrations of surfactant sodium dodecyl sulfate. The influence of gas and liquid flow rates, the viscosity of the liquid phase and the width of the microchannel on the bubble size were explored. The bubble size was correlated as a function of the width of the microchannel W
c, the ratio of the gas/liquid flow rates Q
g/Q
l and the liquid Reynolds number. During the pinch-off stage, the variation of the minimum width of the gaseous thread W
m with the remaining time could be scaled as $$ W_{\text{m}} \propto ({\frac{{Q_{\text{g}} }}{{Q_{\text{l}} }}})^{ - 0.15} (T - t)^{1/3} . $$
The velocity fields in the liquid phase around the thread, determined by μ-PIV measurements, were obtained around a forming bubble to reveal the role of the liquid phase.
62 citations
Cites background or methods from "Formation of bubbles and foams in g..."
...The popular geometries for the production of bubbles and droplets are flow-focusing devices (Cubaud et al. 2005; Dietrich et al. 2008; Dollet et al. 2008; Fu et al. 2009; Gañán-Calvo and Gordillo 2001; Garstecki et al. 2004, 2005; Gordillo et al. 2004; Jensen et al. 2006; Skurtys et al. 2008; Weber and Shandas 2007; Yu et al. 2007), T-junctions based on cross-flowing rupture technique (Garstecki et al....
[...]
...2004); (2) The flow-focusing junction aligned to a small and short orifice, linked to a wide exit (Dollet et al. 2008; Garstecki et al. 2004, 2005; Jensen et al. 2006; Skurtys et al. 2008; Weber and Shandas 2007); (3) The gas and liquid inlet channels and the outlet channel have the same straight geometry (Cubaud et al....
[...]
References
More filters
2,819 citations
TL;DR: In this article, the authors provided a partial theory of the indicator bubble commonly used to measure liquid flowrates in capillaries, and showed that the bubble will not rise at all if where ρ is the difference in density between the fluids inside and outside the bubble.
Abstract: A long bubble of a fluid of negligible viscosity is moving steadily in a tube filled with liquid of viscosity μ at small Reynolds number, the interfacial tension being σ. The angle of contact at the wall is zero. Two related problems are treated here.In the first the tube radius r is so small that gravitational effects are negligible, and theory shows that the speed U of the bubble exceeds the average speed of the fluid in the tube by an amount UW, where (This result is in error by no more than 10% provided ). The pressure drop, P, across such a bubble is given by and W is uniquely determined by conditions near the leading meniscus. The interface near the rear meniscus has a wave-like appearance. This provides a partial theory of the indicator bubble commonly used to measure liquid flowrates in capillaries. A similar theory is applicable to the two-dimensional motion round a meniscus between two parallel plates. Experimental results given here for the value of W agree well neither with theory nor with previous experiments by other workers. No explanation is given for the discrepancies.In the second problem the tube is wider, vertical, and sealed at one end. The bubble now moves under the effect of gravity, but it is shown that it will not rise at all if where ρ is the difference in density between the fluids inside and outside the bubble. If accurate to within 10%. Experiments are adduced in support of these results, though there is disagreement with previous work.
2,135 citations
Book•
[...]
01 Jan 1999
TL;DR: In this article, the shape of single soap movies and bubble clusters is discussed, as well as the condUCTIVITY FORMULA of LEMLICH and PHYLLOTAXIS.
Abstract: PREFACE APPENDICES A. THE SHAPE OF SINGLE SOAP FILMS AND BUBBLES B. THE THEOREM OF LAMARLE C. BUBBLE CLUSTERS D. THE DECORATION THEORUM E. THE CONDUCTIVITY FORMULA OF LEMLICH F. THE DRAINAGE EQUATION G. PHYLLOTAXIS H. SIMULATION OF LIQUID FOAMS I. BIBLIOGRAPHY APPENDICES
1,275 citations
Book•
01 Jan 2017
TL;DR: In this paper, the SI rules for notation for SI units are discussed. But the SI Units System is not defined. And the SI Rule for Notation for SI Quantities is not discussed.
Abstract: Introduction Aspects of Thermodynamics Bonds and Interaction Forces Reaction Kinetics Transport Phenomena Polymers Proteins Water Relations Dispersed Systems Surface Phenomena Formation of Emulsions and Foams Colloidal Interactions Changes in Dispersity Nucleation Crystallization Glass Transitions And Freezing Soft Solids APPENDIX A: Frequently Used Symbols for Physical Quantities APPENDIX B: Some Frequently Used Abbreviations APPENDIX C: Some Mathematical Symbols APPENDIX D: SI Rules for Notation APPENDIX E: The SI Units System APPENDIX F: Some Conversion Factors APPENDIX G: Recalculation of Concentrations APPENDIX H: Physical Properties of Water at 0-100 C APPENDIX I: Thermodynamic and Physical Properties of Water and Ice APPENDIX J: Some Values of the Error Function Index
860 citations
Book•
01 Jan 1873
688 citations