International Journal of Multiphase Flow最新文献

{"title":"Significance of recirculating micro-bubbles in oxygenation from poly-dispersed plumes","authors":"Farzad Faraji Dizaji ,&nbsp;Micheál Cairns ,&nbsp;Thomas Abadie ,&nbsp;Abdulaleem Albadawi ,&nbsp;Robert Connolly ,&nbsp;Ben Breen ,&nbsp;Stefan Berten ,&nbsp;Ugo Bernabo ,&nbsp;Yan Delauré","doi":"10.1016/j.ijmultiphaseflow.2023.104408","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104408","url":null,"abstract":"<div><p>Poly-disperse bubble plumes are simulated to explore the effect of interactions between multiple bubbles of varying sizes on the liquid flow, plume dynamics, and oxygen transfer in aeration processes. An Eulerian-Lagrangian model based on the multiphase particle-in-cell method (MPPIC) implemented in OpenFOAM^TM has been extended to account for bubbly flow. Bubbles have been approximated as spherical particles whose diameters change in response to pressure and nitrogen and oxygen mass dissolution and transfer. The mass transfer model relies on a Sherwood number correlation which accounts for the individual bubble size and relative velocity and is parameterized against the liquid phase temperature. A Large Eddy Simulation (LES) approach based on a transport equation for the turbulent kinetic energy has been adopted to model the effect of the sub-grid scales (SGS) of turbulence on the liquid flow and bubble motion. The bubble injection is defined in terms of the air mass transfer and the bubble size distribution. The model has been compared against experimental measurements of the evolution in oxygen concentration in a <span><math><mrow><mn>1</mn><mspace></mspace><mi>m</mi></mrow></math></span> deep water tank in response to bubble plumes generated from a porous ceramic plates at two different flow rates. The interaction between milli- and micro-bubbles over a wide range of sizes has been shown to create significant differences in the aeration process. A method to correct for bubble recirculation has been proposed and allows for good agreement between measured and simulated volumetric transfer rates. The simulation has shown the important role that the interplay between bubble sizes takes in determining the oxygen transfer efficiency. Larger standard deviations from Gaussian bubble size distributions have been shown in particular to reduce recirculation from smaller bubbles thereby reducing the aeration efficiency at an equivalent flow rate. An analysis of the age distribution by bubble size plumes suggest that the largest bubble have an important role in increasing the entrainment of smaller bubbles limiting their recirculation and reducing their retention time.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"165 ","pages":"Article 104408"},"PeriodicalIF":3.8,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2554033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Derivation and stability analysis of two-fluid model equations for bubbly flow with bubble oscillations and thermal damping","authors":"Takahiro Ayukai ,&nbsp;Tetsuya Kanagawa","doi":"10.1016/j.ijmultiphaseflow.2023.104456","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104456","url":null,"abstract":"<div><p><span><span><span><span>The two-fluid model with bubble oscillations, proposed by Egashira et al. (2004), can explain the properties of cavitating bubbly flow and pressure wave propagation in the bubbly liquid. However, the viscous effect as well as energy conservation leading to temperature changes inside the bubble with bubble oscillations have not yet been considered. Hence, this study aimed to incorporate the viscous (bulk viscosity and drag) and thermal effects to the previously proposed two-fluid model with bubble oscillations. Bulk viscosity was considered by averaging the shear stress term in the single-phase momentum conservation for a </span>Newtonian fluid, and the drag was introduced by transforming the </span>interfacial shear stress. We derived the averaged energy conservation for a general two-phase flow with a </span>thermal conduction inside bubbles and heat transfer between the two phases, and limited this equation to that for a bubbly flow by closing the interfacial </span>temperature gradient term via constitutive equations for a single bubble. Furthermore, we investigated the stability of our proposed one-dimensional model equations using the dispersion analysis. This analysis provided the following insight: (i) The difference in the temperature gradient models had a slight effect on the stability of the proposed model equations; (ii) the thermal conduction inside the bubbles was dominant in the thermal damping in bubbly flows rather than the heat transfer between the two phases; (iii) incorporating both the bulk viscosity and drag stabilized the proposed model equations. Our results provide insights into the development of mathematical models to investigate the thermal effects in bubbly flow with bubble oscillations, such as cavitating bubbly flow and wave propagation in bubbly liquids.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"165 ","pages":"Article 104456"},"PeriodicalIF":3.8,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1632593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slug flows of gas and shear-thinning fluids in horizontal pipes","authors":"R. Baungartner ,&nbsp;G.F.N. Gonçalves ,&nbsp;J.B.R. Loureiro ,&nbsp;A.P. Silva Freire","doi":"10.1016/j.ijmultiphaseflow.2023.104473","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104473","url":null,"abstract":"<div><p><span><span>Experiments on slug flow are carried out with air and three solutions of carboxymethylcellulose (CMC)(0.05, 0.1 and 0.2% w/w) in a 44.2 mm ID horizontal pipe. The lengths, velocities and frequency of passage of the large bubbles are obtained through a high-speed digital camera. The gas fraction and length of liquid slugs<span> are also estimated. Pressure changes along the pipe are measured with a differential pressure transducer. </span></span>Particle Image Velocimetry is used to obtain the mean velocity of the continuous liquid field in the film and slug regions. The combination of tested gas and liquid superficial velocities and of distinct fluid rheology results in 48 different experimental conditions. The flow behavior is found to be strongly dependent on the rheological properties of the continuous phase. In particular, the gas volume fraction within the liquid slug </span><span><math><mrow><mo>(</mo><mi>α</mi><mo>=</mo><mn>1</mn><mo>−</mo><msub><mrow><mi>R</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span>, the passage frequency of the large bubbles (<span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span>) and the pressure changes are increased. New expressions are proposed for <span><math><mi>α</mi></math></span> and <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>t</mi></mrow></msub></math></span><span><span> to account for the rheology of the liquid phase. Predictions of the flow parameters obtained through two modified mechanistic models are compared with the experimental data. The </span>friction coefficient expression proposed by Anbarlooei et al. (Phys. Rev. E, 92(6), 5–9, 2015) is also tested. The impact of the proposed modifications on the calculated properties of slug flow is assessed; typical RMS-errors of less than 15% are obtained for parameter predictions.</span></p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"165 ","pages":"Article 104473"},"PeriodicalIF":3.8,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1750613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alignment of carbon fiber and PDMS mixture flowing in 90° elbow channel","authors":"Hoang Minh Khoa Nguyen,&nbsp;Dong-Wook Oh","doi":"10.1016/j.ijmultiphaseflow.2023.104470","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104470","url":null,"abstract":"<div><p>In this study, flow visualization experiments and computational fluid dynamics simulations are conducted to analyze the rotation of carbon fibers flowing in a 90° elbow channel. In the corner of the 90° elbow channel, a directional change in velocities and velocity gradients results in the rotation of the fibers from a horizontal to vertical alignment. To analyze the fiber rotation, a mixture comprising uncured polydimethylsiloxane and ball-milled carbon fibers is utilized as the working fluid in a flow visualization experiment. The velocity and velocity gradients inside the channel are calculated via computational fluid dynamics simulation and then compared with the angular changes in the fiber rotation along different trajectories inside the elbow corner. A Lagrangian approach using a local coordinate system to trail each fiber along the trajectory is utilized to compare the effects of shear rate on fiber rotation. It is discovered that the fibers are affected by a relatively high local shear rate, and that they propagate with the flow, indicating a parallel alignment in the flow direction while exhibiting a 90° turn at the elbow corner.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"165 ","pages":"Article 104470"},"PeriodicalIF":3.8,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1517260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights on bubble encapsulation after drop impact on thin liquid films","authors":"Daniela F.S. Ribeiro ,&nbsp;Miguel R.O. Panão ,&nbsp;Jorge M.M. Barata ,&nbsp;André R.R. Silva","doi":"10.1016/j.ijmultiphaseflow.2023.104450","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104450","url":null,"abstract":"<div><p>The accurate understanding of the phenomenology of drop impact onto dry/ wetted and cold/heated surfaces is increasingly relevant to implement biofuels in civil aviation. The outcome of drop impact depends on the pre-impact conditions and a seldom researched event is the encapsulation of a bubble when this impact occurs on thin liquid films. Therefore, the goal of the experimental work reported is to investigate the mechanism of this bubble encapsulation. Results show that the mechanism leading to a bubble formation has two stages. In the first stage, after the drop impacts a steady liquid film, a prompt splash occurs followed by a crown splash. The uprising sheet propagates in an almost normal direction relative to the liquid film, but its radius at the base continues to expand, eventually leading to the inward collapse of the crown-bounding rim encapsulating air inside the dome. In the second stage, three different phenomenologies of bubble encapsulation can occur. At the top of the closed crown, one jet (phenomenology 1) or two jets are formed (phenomenologies 2 and 3). For phenomenology 2, the upward jet eventually collapses due to gravitational influence, while the downward jet continues to grow until it reaches the liquid film, attaching to it, stretching and detaching from the top at the hemispheric thin sheet, forming a bubble. In phenomenology 3, the upward jet is high enough to allow its breakup and ejection of one large droplet before the collapse of the upward jet. Many secondary droplets fall on the bubble and one of them will eventually break the dome, leading to more secondary atomization. Additionally, the first perturbation imposed on the liquid film by the droplet impact is studied and an empirical correlation is proposed for its propagation velocity. Finally, bubble geometry is investigated.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"164 ","pages":"Article 104450"},"PeriodicalIF":3.8,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3451640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on spatial-temporal evolution of tip leakage cavitation in a mixed flow pump with tip clearance","authors":"Yadong Han,&nbsp;Lei Tan","doi":"10.1016/j.ijmultiphaseflow.2023.104445","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104445","url":null,"abstract":"<div><p>Tip leakage cavitation remains an unsolved problem that threatens the safe operation of hydraulic machines and plagues researchers worldwide. The objective of this work is to investigate the classification and spatial-temporal evolution of tip leakage cavitation, and even to provide additional insights into the flow physics. Experiments are conducted in a mixed flow pump installed on a closed-loop test rig. High-speed visualizations are performed to capture the flow patterns of tip leakage cavitation at rated flow rate. It is demonstrated that tip leakage vortex cavitation can be categorized as primary tip leakage vortex cavitation (PTLVC) and secondary tip leakage vortex cavitation (STLVC). A new tip leakage cavitation structure, named as the double-hump PTLVC, is firstly observed in the mixed flow pump under severe cavitation conditions. The spatial-temporal evolution of the double-hump PTLVC is classified into four stages: incepting stage, growing stage, merging stage and propagating stage. The averaged propagating velocity of the front hump of PTLVC increases with decreasing net positive suction head (NPSH), and reaches the maximum of 0.38 <em>U</em>_tip in the present experiment. Three empirical functions are proposed to describe the relationship between projected area, the maximum axial thickness, circumferential collapse position and NPSH, respectively. It is found that for every 0.1 m drop in NPSH, the projected area increases by about 2.1%, the maximum axial thickness increases by about 2.7%, and the circumferential length of the PTLVC increases by about 3.5%, respectively.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"164 ","pages":"Article 104445"},"PeriodicalIF":3.8,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1518256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quasi-steady evaporation of deformable liquid fuel droplets","authors":"Meha Setiya,&nbsp;John Palmore Jr","doi":"10.1016/j.ijmultiphaseflow.2023.104455","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104455","url":null,"abstract":"<div><p><span><span>This work covers the effect of droplet deformation on its evaporation rate under </span>convective flow<span> conditions. The evaporation behavior of a freely deforming droplet of single component jet fuel surrogate, n-decane, is investigated by varying Weber number (</span></span><span><math><mrow><mi>W</mi><mi>e</mi></mrow></math></span>) from <span><math><mrow><mn>1</mn><mtext>–</mtext><mn>12</mn></mrow></math></span><span> and Reynolds number (</span><span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span><span>) from 25 to 120 under high-pressure environment. These studies utilize interface capturing Direct Numerical Simulation (DNS). To validate the accuracy of the solver, the results are compared against correlations by Abramzon and Sirignano (Int. Journal of Heat and Mass Transfer, 1989) and are found to be in good agreement with a maximum difference of 5%. A quasi-steady evaporation approach is implemented to simulate this problem. The results suggest a weak dependency of normalized total evaporation rate (</span><span><math><msub><mrow><mover><mrow><mi>m</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow><mrow><mi>N</mi><mi>D</mi></mrow></msub></math></span>) on Weber number at low <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> flow. However, a strong correlation is seen between the total evaporation rate and <span><math><mrow><mi>W</mi><mi>e</mi></mrow></math></span> at high <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span>. 20% enhancement in <span><math><msub><mrow><mover><mrow><mi>m</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow><mrow><mi>N</mi><mi>D</mi></mrow></msub></math></span> is observed at <span><math><mrow><mi>W</mi><mi>e</mi><mo>=</mo><mn>12</mn></mrow></math></span> (highly deformed shape) when compared to <span><math><mrow><mi>W</mi><mi>e</mi><mo>=</mo><mn>1</mn></mrow></math></span> at <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>120</mn></mrow></math></span>.</p><p>In these cases, the distribution of local evaporation flux on the droplet is found to be proportional to its curvature up to the point of flow separation which agrees with low <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> theories on droplet evaporation by Tonini and Cossalli (International Journal of Heat and Mass Transfer 2013), Palmore (Journal of Heat Transfer 2022). Beyond the flow separation point, evaporation flux distribution depends on the boundary layer development and flow evolution downstream of the droplet. For highly deformed droplets, a larger wake region creates favorable fuel vapor gradients and promotes mixing in droplet wake, hence higher evaporation flux.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"164 ","pages":"Article 104455"},"PeriodicalIF":3.8,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1518260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rarefaction effects in head-on collision of two near-critical droplets","authors":"Tao Chen ,&nbsp;Lei Wu ,&nbsp;Lian-Ping Wang ,&nbsp;Shiyi Chen","doi":"10.1016/j.ijmultiphaseflow.2023.104451","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104451","url":null,"abstract":"<div><p>The head-on collision of two droplets near the critical point is investigated based on the Boltzmann-BGK equation. Gauss–Hermite quadratures with different degree of precision are used to solve the kinetic equation, so that the solutions truncated at the Navier–Stokes order and non-continuum (i.e., rarefied fluid dynamics) solutions can be compared. When the kinetic equation is solved with adequate accuracy, prominent variations of the vertical velocity (the collision is in the horizontal direction), the viscous stress components, and droplet morphology are observed during the formation of liquid bridge, which demonstrates the importance of the rarefaction effects and the failure of the Navier–Stokes equation. The rarefaction effects change the topology of streamlines near the droplet surface, suppress the high-magnitude vorticity concentration inside the interdroplet region, and promote the vorticity diffusion around outer droplet surface. Two physical mechanisms responsible for the local energy conversion between the free and kinetic energies are identified, namely, the total pressure-dilatation coupling effect and the interaction between the density gradient and strain rate tensor. An energy conversion analysis is performed to show that the rarefaction effects can enhance the conversion from free energy to kinetic energy and facilitate the discharge of the gas interval along the vertical direction, thereby boosting droplet coalescence. Furthermore, the magnitude and the spatial oscillation frequency of the Lamb vector divergence inside the gas interval are shown to be suppressed by the rarefaction effects. It is found that the dynamic process in the gas interval is closely associated with the interaction between the adjacent positive and negative regions of the Lamb vector divergence.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"164 ","pages":"Article 104451"},"PeriodicalIF":3.8,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1518258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of flow-blurring atomization with Smoothed Particle Hydrodynamics (SPH)","authors":"Cihan Ates ,&nbsp;Cansu Gundogdu ,&nbsp;Max Okraschevski ,&nbsp;Niklas Bürkle ,&nbsp;Rainer Koch ,&nbsp;Hans-Jörg Bauer","doi":"10.1016/j.ijmultiphaseflow.2023.104442","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104442","url":null,"abstract":"<div><p><span>The liquid atomization<span> process relies on the disturbance of the liquid surface by various forces. In the case of “flow-blurring” (FB) atomization, this is achieved by inducing flow instabilities near the liquid channel exit. In this study, we analyze the underlying dynamics of these coherent turbulent structures and their role in the primary atomization within the FB regime. For that purpose, Smoothed Particles Hydrodynamics (SPH) simulations have been conducted using alternative FB nozzle geometries at different operating conditions. An in-house developed visualization and data exploration platform (postAtom) was used to capture the time-resolved Lagrangian coherent structures (</span></span><span><math><mi>LCSs</mi></math></span><span>) via the finite-time Lyapunov exponent (</span><span><math><mi>FTLE</mi></math></span><span>) fields. Simulations were conducted at different gas/liquid momentum ratios at the nozzle exit<span> by changing the mass flow rate<span> of the gas phase and/or changing the position of the liquid injector<span>. The effect of outer chamber design on the atomization performance is further assessed. The results indicate that the design of the mixing chamber can trigger an oscillatory behavior at the nozzle exit, which has a direct impact on the evolution of the micro-ligaments and the consecutive primary atomization. Comparisons between different operating points further reveal that FB atomization may not be achieved if the gas momentum is below a certain threshold value.</span></span></span></span></p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"164 ","pages":"Article 104442"},"PeriodicalIF":3.8,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1750616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional evolution and interaction of disturbance waves on a gas-sheared liquid film on a horizontal plane near the transition region","authors":"Andrey V. Cherdantsev","doi":"10.1016/j.ijmultiphaseflow.2023.104468","DOIUrl":"https://doi.org/10.1016/j.ijmultiphaseflow.2023.104468","url":null,"abstract":"<div><p>Disturbance waves are complex three-dimensional large-scale structures appearing on liquid films under strong gas shear. They strongly intensify heat, mass and momentum interchange between the phases, thus affecting the efficiency of industrial equipment. Here we analyze inception and three-dimensional spatiotemporal evolution of disturbance waves on a gas-sheared liquid film flowing along the bottom of a wide horizontal duct. The experiments are carried out using Brightness-Based Laser-Induced Fluorescence technique in a large region of interrogation with length of 380 mm and width of 166 mm (equal to the width of the duct). The range of gas superficial velocities is from 6 to 24 m/s with a step of 2 m/s; the range of liquid wetting densities is from 1 to 8 cm²/s with a step of 1 cm²/s. Three working liquids with different viscosity and surface tension are employed. Transition from small-scale 3D-waves to disturbance waves is identified; it is shown that the transition becomes less sensitive to liquid properties and flow rate as the liquid flow rate increases. An intermediate stage of the transition is the formation of smooth-interface patches with low amplitude and large longitudinal and transverse size. Quantitative criteria to identify the transition are proposed. The side walls of the duct mainly affect the amplitude and local longitudinal size of disturbance waves by distorting the shape of disturbance wave fronts. As a result, local time-averaged film thickness increases near the side walls. The disturbance waves are essentially three-dimensional with curved fronts and a wide range of transverse size. The width of a wave exerts a strong influence on its amplitude, velocity, and longitudinal size. Coalescence of disturbance waves is a three-dimensional phenomenon leading to elimination of narrow waves; as the flow develops, it becomes more uniform in transverse direction.</p></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"164 ","pages":"Article 104468"},"PeriodicalIF":3.8,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1750622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}