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Boček Ž, Petkovšek M, Clark SJ, Fezzaa K, Dular M. Kelvin-Helmholtz instability as one of the key features for fast and efficient emulsification by hydrodynamic cavitation. ULTRASONICS SONOCHEMISTRY 2024; 108:106970. [PMID: 38943847 PMCID: PMC11261489 DOI: 10.1016/j.ultsonch.2024.106970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/01/2024]
Abstract
The paper investigates the oil-water emulsification process inside a micro-venturi channel. More specifically, the possible influence of Kelvin-Helmholtz instability on the emulsification process. High-speed visualizations were conducted inside a square venturi constriction with throat dimensions of 450 µm by 450 µm, both under visible light and X-Rays. We show that cavity shedding caused by the instability results in the formation of several cavity vortices. Their rotation causes the deformation of the oil stream into a distinct wave-like shape, combined with fragmentation into larger drops due to cavitation bubble collapse. Later on, the cavity collapse further disperses the larger drops into a finer emulsion. Thus, it turns out that the Kelvin-Helmholtz instability is similarly characteristic for hydrodynamic cavitation emulsification inside a microchannel as is the Rayleigh-Taylor instability for acoustically driven emulsion formation.
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Affiliation(s)
- Žan Boček
- Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, 1000 Ljubljana, Slovenia
| | - Martin Petkovšek
- Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, 1000 Ljubljana, Slovenia
| | - Samuel J Clark
- Advanced Photon Source, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL 6043, USA
| | - Kamel Fezzaa
- Advanced Photon Source, Argonne National Laboratory, 9700 S Cass Ave, Lemont, IL 6043, USA
| | - Matevž Dular
- Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, 1000 Ljubljana, Slovenia.
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Upadhyay M, Ravi A, Ranade VV. Dense Oil in Water Emulsions using Vortex-Based Hydrodynamic Cavitation: Effective Viscosity, Sauter Mean Diameter, and Droplet Size Distribution. Ind Eng Chem Res 2024; 63:4977-4990. [PMID: 38525289 PMCID: PMC10958511 DOI: 10.1021/acs.iecr.3c04555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/25/2024] [Accepted: 02/28/2024] [Indexed: 03/26/2024]
Abstract
Vortex-based hydrodynamic cavitation offers an effective platform for producing emulsions. In this work, we have investigated characteristics of dense oil in water emulsions with oil volume fractions up to 60% produced using a vortex-based cavitation device. Emulsions were prepared using rapeseed oil with oil volume fractions of 0.15, 0.3, 0.45, and 0.6. For each of these volume fractions, the pressure drop as a function of the flow rate of emulsions through the cavitation device was measured. These data were used for estimating the effective viscosity of the emulsions. The droplet size distribution of the emulsions was measured using the laser diffraction technique. The influence of the number of passes through the cavitation device on droplet size distributions and the Sauter mean diameter was quantified. It was found that the Sauter mean diameter (d32) decreases with an increase in the number of passes as n-0.2. The Sauter mean diameter was found to be almost independent of oil volume fraction (αo) up to a certain critical volume fraction (αoc). Beyond αoc, d32 was found to be linearly proportional to a further increase in oil volume fraction. As expected, the turbidity of the produced emulsions was found to be linearly proportional to the oil volume fraction. The slope of turbidity versus oil volume fraction can be used to estimate the Sauter mean diameter. A suitable correlation was developed to relate turbidity, volume fraction, and Sauter mean diameter. The droplet breakage efficiency of the vortex-based cavitation device for dense oil in water emulsions was quantified and reported. The breakage efficiency was found to increase linearly with an increase in oil volume fraction up to αoc and then plateau with a further increase in the oil volume fraction. The breakage efficiency was found to decrease with an increase in energy consumption per unit mass (E) as E-0.8. The presented results demonstrate the effectiveness of a vortex-based cavitation device for producing dense oil in water emulsions and will be useful for extending its applications to other dense emulsions.
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Affiliation(s)
| | | | - Vivek V. Ranade
- Multiphase Reactors and Intensification
Group Bernal Institute, University of Limerick, Limerick V94T9PX, Ireland
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Gode A, Madane K, Ranade VV. Design of vortex-based cavitation devices/reactors: Influence of aspect ratio, number of inlets and shape. ULTRASONICS SONOCHEMISTRY 2023; 101:106695. [PMID: 38011805 PMCID: PMC10767635 DOI: 10.1016/j.ultsonch.2023.106695] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/30/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023]
Abstract
Vortex-based hydrodynamic cavitation devices are being used in a wide range of applications. However, adequate information on the design of such devices is not available. In this work, we have computationally investigated the influence of key design parameters such as the aspect ratio of the vortex chamber, the number of tangential inlets and the shape of the device on resulting flow characteristics and cavitation. Experiments were carried out to validate key findings from the computational studies. These investigations revealed that the aspect ratio of the vortex chamber as six may be considered as optimum. The performance of single and multiple inlet devices was found to be comparable at the same pressure drop (that is at same energy consumption per m3). Scale-up with a geometric similarity led to a reduction in the extent of cavitation for same energy consumption per m3. For facilitating scale-out option, an attempt was made to simplify the configuration of the vortex-based cavitation device. Computational results indicated that the cavitation performance of simplified configuration was not significantly inferior. A case of the formation of liquid-liquid emulsion was taken as a test case for evaluation of a modified cavitation device based on the present investigations. The droplet size distributions of emulsions generated by both the devices indicate that the proposed simplified configuration, which may facilitate fabrication and offer integrated scale-out options, performs almost at par with a complex configuration. The presented results will be useful for optimising designs of vortex-based hydrodynamic cavitation devices/ reactors.
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Affiliation(s)
- Amol Gode
- Multiphase Reactors and Intensification Group (mRING), Bernal Institute, University of Limerick, Ireland
| | - Ketan Madane
- Multiphase Reactors and Intensification Group (mRING), Bernal Institute, University of Limerick, Ireland
| | - Vivek V Ranade
- Multiphase Reactors and Intensification Group (mRING), Bernal Institute, University of Limerick, Ireland.
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Soyama H, Liang X, Yashiro W, Kajiwara K, Asimakopoulou EM, Bellucci V, Birnsteinova S, Giovanetti G, Kim C, Kirkwood HJ, Koliyadu JCP, Letrun R, Zhang Y, Uličný J, Bean R, Mancuso AP, Villanueva-Perez P, Sato T, Vagovič P, Eakins D, Korsunsky AM. Revealing the origins of vortex cavitation in a Venturi tube by high speed X-ray imaging. ULTRASONICS SONOCHEMISTRY 2023; 101:106715. [PMID: 38061251 PMCID: PMC10750113 DOI: 10.1016/j.ultsonch.2023.106715] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/18/2023] [Accepted: 12/01/2023] [Indexed: 12/22/2023]
Abstract
Hydrodynamic cavitation is useful in many processing applications, for example, in chemical reactors, water treatment and biochemical engineering. An important type of hydrodynamic cavitation that occurs in a Venturi tube is vortex cavitation known to cause luminescence whose intensity is closely related to the size and number of cavitation events. However, the mechanistic origins of bubbles constituting vortex cavitation remains unclear, although it has been concluded that the pressure fields generated by the cavitation collapse strongly depends on the bubble geometry. The common view is that vortex cavitation consists of numerous small spherical bubbles. In the present paper, aspects of vortex cavitation arising in a Venturi tube were visualized using high-speed X-ray imaging at SPring-8 and European XFEL. It was discovered that vortex cavitation in a Venturi tube consisted of angulated rather than spherical bubbles. The tangential velocity of the surface of vortex cavitation was assessed considering the Rankine vortex model.
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Affiliation(s)
- Hitoshi Soyama
- Department of Finemechanics, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai 980-8579, Japan.
| | - Xiaoyu Liang
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Wataru Yashiro
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, Miyagi 980-8577, Japan; International Center for Synchrotron Radiation Innovation Smart (SRIS), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, Miyagi 980-8577, Japan; Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kentaro Kajiwara
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | | | | | | | | | - Chan Kim
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | | | | | - Romain Letrun
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Yuhe Zhang
- Synchrotron Radiation Research and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Jozef Uličný
- Faculty of Science, Department of Biophysics, P. J. Šafárik University, Jesenná 5, 04154 Košice, Slovakia
| | - Richard Bean
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Adrian P Mancuso
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Diamond House, Didcot, OX11 0DE, UK; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Pablo Villanueva-Perez
- Synchrotron Radiation Research and NanoLund, Lund University, Box 118, Lund, 221 00, Sweden
| | - Tokushi Sato
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Patrik Vagovič
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany; Center for Free-Electron Laser (CFEL), DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Daniel Eakins
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Alexander M Korsunsky
- Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
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Delaney P, Sarvothaman VP, Nagarajan S, Rooney D, Robertson PKJ, Ranade VV. Oxidation of Sulphur pollutants in model and real fuels using hydrodynamic cavitation. ULTRASONICS SONOCHEMISTRY 2023; 95:106405. [PMID: 37084535 PMCID: PMC10148227 DOI: 10.1016/j.ultsonch.2023.106405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/25/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Hydrodynamic Cavitation (HC) offers an attractive platform for intensifying oxidative desulphurization of fuels. In the first part of this work, we present new results on oxidising single ring thiophene in a model fuel over the extended range of volume fraction of organic phase from 2.5 to 80 v/v %. We also present influence of type and scale of HC device on performance of oxidative desulphurization. Further experiments revealed that oxidising radicals generated in-situ by HC alone were not able to oxidise dual ring thiophenes. External catalyst (formic acid) and oxidising agents (hydrogen peroxide, H2O2) were therefore used with HC. Based on our prior work with acoustic cavitation (AC), the volumetric ratios for H2O2 and formic acid were identified as 0.95 v/v % and 6.25 v/v % respectively. The data of oxidation of dual ring thiophenes with n-dodecane and n-hexane as model fuels and typical transport fuels (diesel, kerosene, and petrol) using these oxidant and catalyst is presented. The observed performance with HC was compared with results obtained from a stirred tank and AC set-up. The presented data indicates that HC is able to intensify oxidation of sulphur species. The presented results provide a sound basis for further developments on HC based oxidative desulphurization processes.
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Affiliation(s)
- Peter Delaney
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, UK
| | - Varaha P Sarvothaman
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, UK; Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Sanjay Nagarajan
- Sustainable Environment Research Centre, University of South Wales, Pontypridd CF37 1DL, UK
| | - David Rooney
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, UK
| | - Peter K J Robertson
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, UK
| | - Vivek V Ranade
- School of Chemistry and Chemical Engineering, Queen's University Belfast, Belfast BT9 5AG, UK; Bernal Institute, University of Limerick, Limerick, Ireland.
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