International Journal of Multiphase Flow最新文献

{"title":"Transition to entrainment in downward annular gas-liquid flow: Study through flow control","authors":"Andrey Cherdantsev,&nbsp;Sergey Isaenkov,&nbsp;Dmitry Markovich","doi":"10.1016/j.ijmultiphaseflow.2024.105109","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105109","url":null,"abstract":"<div><div>Formation of disturbance waves and entrainment of liquid droplets drastically enhances pressure drop and heat and mass transfer in annular flow. Here we investigate the transition to entrainment by analyzing spatiotemporal records of film thickness in the vicinity of the transition border. Two branches of the border: “vertical”, with high gas speeds and low liquid flow rates, and “horizontal”, with low gas speeds and large liquid flow rates, are analyzed separately. In both cases, low-frequency pulsations of liquid flow rate are applied in attempt to expand the regime area of entrainment and learn more about the transition. It was found that two conditions are necessary for creation of a disturbance wave: strong localized perturbations able to create the initial hump of liquid and enough spare liquid in excess of the viscous sub-layer to fill and maintain this hump. Below the “vertical” branch, the disturbance waves do not occur due to lack of spare liquid. Below the “horizontal” branch, no sources of strong perturbations are present. Both “vertical” and “horizontal” branches can be shifted towards lower values of liquid flow rate and gas speed, respectively, using low-frequency oscillations of liquid flow rate. However, the mechanisms of creating these artificial disturbance waves are different. For “vertical” branch, the pulsations create patches of larger liquid flow rate, where disturbance waves can be created in a “natural” manner. For “horizontal” branch, each pulsation period creates a single disturbance wave, provided that the excitation frequency belongs to appropriate range.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105109"},"PeriodicalIF":3.6,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137397","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":"Prediction of bubbly flow and flow regime development in a horizontal air-water pipe flow with a morphology-adaptive multifluid CFD model","authors":"Marco Colombo ,&nbsp;Michael Fairweather","doi":"10.1016/j.ijmultiphaseflow.2024.105112","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105112","url":null,"abstract":"<div><div>Most multiphase gas-liquid flows of industrial and engineering interest often encompass multiple flow regimes and the transition between them. The wide range of interface scales involved is challenging to model, and this has so far limited the application of computational fluid dynamics to multi-regime flows and complex multiphase flow conditions. The morphology-adaptive GEneralized Multifluid Modelling Approach (GEMMA), developed in OpenFOAM, is designed to provide all-flow-regime modelling capabilities. The model implements in the multifluid modelling framework interface-resolving capabilities that are used to treat large-scale interfaces found in segregated flow regimes, while dispersed regimes remain modelled with the standard multifluid approach. In this paper, GEMMA is used to predict, for the horizontal pipe flow studied in the METERO experiment (Bottin et al., 2014), the development of the bubbly, plug, slug and stratified flow regimes starting from a homogeneous 1 mm bubble distribution at the inlet of the pipe. In the bubbly regime, the model predicts well the void fraction and bubble diameter distributions, but not the lower flow velocity when a bubble layer accumulates at the top of the pipe. Results also show that modelling closures developed mainly for vertical flow conditions, and which are a strong function of the relative velocity, may not be equipped to predict horizontal flows where relative velocities can be negligible. Beyond the bubbly regime, the model predicts the development of intermittent gas plugs, the increase in the length scale of the plugs approaching the transition to slug flow and the development of a stratified flow at the lowest water flow rate. The velocity of gas plugs is found to be in good agreement with literature models. Challenging to predict remains the transition region from bubbly to plug and from slug to stratified flow, where an anticipated transition to stratified flow is predicted in the slug regime. Overall, GEMMA provides a morphology-adaptive modelling framework that can achieve all-flow regime applicability, and the present work is a first demonstration of its capabilities for horizontal flow regimes. Short-term development needs are highlighted, such as additional validation and the improvement of bubbly flow closures, and the modelling of the dispersion and breaking-up of large interfaces to prevent excessive phase agglomeration.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105112"},"PeriodicalIF":3.6,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143138006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of two-phase turbulent modalities and bubble-induced turbulence on polydispersed bubbly flow in continuous casting mold","authors":"Yu Li ,&nbsp;Zhongqiu Liu ,&nbsp;Yuchao Yao ,&nbsp;Baokuan Li ,&nbsp;Guodong Xu","doi":"10.1016/j.ijmultiphaseflow.2024.105104","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105104","url":null,"abstract":"<div><div>A crucial challenge for gas-liquid two-phase flow is modeling two-phase turbulent modalities and bubble-induced turbulence (BIT). Although many shear-induced turbulence (SIT) models have been established and widely used in single-phase flow, there is no consensus on extending single-phase flow to gas-liquid flow. This work presents the development of the novel population balance model (PBM) for simulating multiphase flows in continuous casting (CC) mold. The effect of two-phase turbulent modalities, SIT and BIT mechanisms on flow pattern, bubble distribution and bubble diameter were studied and against with the experimental data. The results show that the RNG model shows better agreement than other models for predicting flow patterns and bubble size. Compared with the experimental values, the mean relative error of Sauter mean diameter is 5.74 %. Furthermore, the correlation between three turbulent modalities and the SIT has been revealed. The turbulence properties predicted by dispersed-modality and per-modality are highly consistent, and the mixture-modality extremely overestimates the bubble size. The dispersed-modality is suitable for simulating gas-liquid flow for CC mold. Finally, we reveal the coupling mechanism between BIT and SIT models. The Simonin model is insufficient to describe the BIT effect due to the low momentum exchange. The Sato model only caused slight perturbation for the Standard model and significantly increased the turbulence viscosity predicted by RNG model. The coupling between the RNG and Sato models can achieve a circulation feedback effect.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105104"},"PeriodicalIF":3.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137390","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":"Freely falling cylinders of length to diameter ratio around one","authors":"G. Bouchet ,&nbsp;J. Dušek","doi":"10.1016/j.ijmultiphaseflow.2024.105097","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105097","url":null,"abstract":"<div><div>The paper presents numerical simulations of the free fall of homogeneous cylinders of length to diameter ratios 0.8 through 1.6 and solid to fluid density ratios <span><math><mrow><msub><mrow><mi>ρ</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>/</mo><mi>ρ</mi></mrow></math></span> going from 0 to 5 in transitional regimes. The results shed light on the transition from flat cylinders falling with their axis oriented vertically or oscillating about this equilibrium position to oblong cylinders keeping a horizontal or predominantly horizontal orientation. A significant bi-stability region extending as much as to an interval of <span><math><mrow><mi>L</mi><mo>/</mo><mi>d</mi></mrow></math></span> ratios of <span><math><mrow><mn>0</mn><mo>.</mo><mn>9</mn><mo>≤</mo><mi>L</mi><mo>/</mo><mi>d</mi><mo>≤</mo><mn>1</mn><mo>.</mo><mn>35</mn></mrow></math></span> shortly before the onset of path instabilities has been evidenced. With the onset of path instabilities, the scenario starts to depend on the density ratio and the bi-stability domain progressively disappears. In these regimes, cylinders of length to diameter ratio 0.9 and 1 are observed to change periodically or intermittently the orientation of their axis. Cylinders of ratio <span><math><mrow><mi>L</mi><mo>/</mo><mi>d</mi><mo>=</mo><mn>1</mn><mo>.</mo><mn>6</mn></mrow></math></span> behave qualitatively like those of ratio <span><math><mrow><mi>L</mi><mo>/</mo><mi>d</mi><mo>≥</mo><mn>2</mn></mrow></math></span> investigated elsewhere and present subcritical effects for density ratio of 5.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105097"},"PeriodicalIF":3.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137400","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":"3D measurement of interfacial mass transfer of isolated millimetric bubbles in turbulence: Multi-view SI-VILF technique and simultaneous reconstruction of deforming bubble interface and surrounding concentration field","authors":"Guangyuan Huang,&nbsp;Bifan Liu,&nbsp;Yuchen Song,&nbsp;Junlian Yin,&nbsp;Dezhong Wang","doi":"10.1016/j.ijmultiphaseflow.2024.105106","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105106","url":null,"abstract":"<div><div>To deepen the understanding of the fundamentals of gas dissolution or absorption within turbulent bubbly flows, experiments of interfacial mass transfer should be performed on isolated bubbles in turbulence, while it remains pending for decades. In this paper, we propose a novel idea for indirectly determining the mass transfer coefficient <span><math><msub><mi>k</mi><mi>L</mi></msub></math></span>based on the law of conservation of mass, avoiding the challenging task of resolving the thin boundary layer at the bubble interface. Based on this idea, the multi-view SI-VLIF technique is developed for 3D measurement of the dissolution of single finite-size oxygen bubbles in turbulent environments. To handle the problem of sparse-view limited-angle imaging, improved 3D reconstruction approaches for the quantities to be measured are developed. The reconstruction qualities are evaluated utilizing synthetic and simulation datasets, and the overall uncertainty in quantifying the <span><math><msub><mi>k</mi><mi>L</mi></msub></math></span> is approximately 7%. Lastly, experiments on the oxygen dissolution of millimetric bubbles in quiescent liquid and nearly homogeneous isotropic turbulence are conducted to demonstrate the novel measuring technique. To our knowledge, this is the first time that the 3D mass transfer processes around a deforming bubble rising in turbulent environments are revealed.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105106"},"PeriodicalIF":3.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137393","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":"Spatial evolution of droplet size and velocity characteristics in a swirl spray","authors":"S.K. Vankeswaram ,&nbsp;V. Kulkarni ,&nbsp;S. Deivandren","doi":"10.1016/j.ijmultiphaseflow.2024.105076","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105076","url":null,"abstract":"<div><div>Spray drop size distribution generated by atomization of fuel influences several facets of a combustion process such as, fuel–air mixing, reaction kinetics and thrust generation. In a typical spray, the drop size distribution evolves spatially, varying significantly between the near and far regions of the spray. However, studies so far have focused exclusively on either one of these regions and are unclear on the exact axial location where transition from near to far region droplet size characteristics is expected. In this work, we address this crucial gap by considering a swirl atomizer assembly and measuring the droplet characteristics for different liquid flow conditions of the ensuing spray at various radial and axial locations. Our results reveal an undiscovered axial variation in the scaled radial droplet velocity profiles, not followed by the radial drop size profiles, from which we unambiguously demarcate the near region as the zone which extends up to axial distances of 2.0 to 2.5 times film breakup length. Beyond this distance, the drop size characteristics are influenced by external factors such as airflow and identified as the far region of the spray. Using our analysis we locate the point of origin of the commonly reported droplet high-velocity stream along the spray centerline to the end of film breakup or near region of the spray. We also find that the global probability density functions for droplet size and velocity which show a marked difference in the near and far regions; being bimodal in the near-region and unimodal in the far-region being well represented by the double Gaussian and the Gamma distributions, respectively. We further quantify our results by meticulous measurements of number and volume flux distributions, global mean drop sizes, drop size (<span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span>) axial velocity (<span><math><msub><mrow><mi>U</mi></mrow><mrow><mi>a</mi></mrow></msub></math></span>) correlations, axial velocity based on drop size classification and turbulent kinetic energy (TKE) which reveal the effect of drop inertia and air flow in determining the statistics in both the near and far regions. We anticipate the findings of this work will guide future investigations on combustion processes and combustor design based on spray characteristics.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105076"},"PeriodicalIF":3.6,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137394","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":"Effect of polydispersity in droplet-driven flows","authors":"Sukruth Satheesh,&nbsp;Pierre Bragança,&nbsp;Christophe Cuvier,&nbsp;John-Christos Vassilicos,&nbsp;Jean-Marc Foucaut","doi":"10.1016/j.ijmultiphaseflow.2024.105080","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105080","url":null,"abstract":"<div><div>Experiments were performed on agricultural flat-fan sprays to elucidate the effect of polydisperse droplets on air induction and entrainment process using shadowgraphy and PIV. Results indicated air motion in flat-fan sprays being close to elliptical jet in terms of its growth, but velocity decay to be dependent on spray spread angle and particle size distribution. Continuous transfer of momentum from droplets of all sizes to air was observed across all measurement planes, with the velocity of smaller droplets dropping quicker to match induced air velocity values than larger ones. Most of the droplets traversed almost in a ballistic manner with only a small fraction of them interacting with air. Experiments in interacting sprays presented greater uniformity in droplet sizes, and near constant unidirectional droplet and air velocities over larger distances.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105080"},"PeriodicalIF":3.6,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137399","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":"Two-dimensional particle-resolved numerical simulation for burning particles in laminar boundary layer flows","authors":"Kaiyue Wang,&nbsp;Haiou Wang,&nbsp;Kun Luo,&nbsp;Jianren Fan","doi":"10.1016/j.ijmultiphaseflow.2024.105079","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105079","url":null,"abstract":"<div><div>In the present work, two-dimensional particle-resolved simulations of burning char particles near the wall were performed to understand the effects of gap ratio, <span><math><mrow><mi>G</mi><mo>/</mo><mi>D</mi></mrow></math></span>, and particle distance, <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span>, on the char combustion process of two burning particles, where <span><math><mi>D</mi></math></span> is the particle diameter, <span><math><mi>G</mi></math></span> is the the distance between the bottom of the particle and the wall, and <span><math><mi>L</mi></math></span> is the distance between the two particles. The results indicate that as <span><math><mrow><mi>G</mi><mo>/</mo><mi>D</mi><mspace></mspace></mrow></math></span>increases, both heterogeneous and homogeneous reaction rates of the particles increase. With <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mo>=</mo><mspace></mspace><mn>1.5</mn></mrow></math></span>, the combustion of two particles can be regarded as an entity. As <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span> increases, the reaction rate of the particles also rises. With <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi><mspace></mspace><mo>=</mo><mspace></mspace><mn>6.0</mn></mrow></math></span>, the two particles are burning independently. The transport budgets of species on the particle surface are examined. The results show that diffusion and reaction dominate the transport of gascous species on the particle surface, while small <span><math><mrow><mi>G</mi><mo>/</mo><mi>D</mi></mrow></math></span> and<span><math><mrow><mspace></mspace><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span> can inhibit species exchange on the surface. The drag and lift forces on combustion particles are measured. It is shown that increasing <span><math><mrow><mi>G</mi><mo>/</mo><mi>D</mi></mrow></math></span> and <span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span> results in increased the drag force of the particles, while the lift force first increases and then decreases with increasing <span><math><mrow><mi>G</mi><mo>/</mo><mi>D</mi></mrow></math></span>. Further investigation of the local drag force shows that the increase in drag force is due to the rise in the pressure component from the increased pressure drop and the rise in shear drag from both increased velo city gradient and kinematic viscosity.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105079"},"PeriodicalIF":3.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137402","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":"Dispersions in three-phase high pressure slug flows based on X-ray measurements","authors":"G.W. Johnson ,&nbsp;T.K. Kjeldby ,&nbsp;P.S. Johansson","doi":"10.1016/j.ijmultiphaseflow.2024.105099","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105099","url":null,"abstract":"<div><div>An X-ray instrument was used to measure phase fractions for three phases over the pipe cross section in upward inclined three-phase flows at high pressure at <span><math><mrow><mn>40</mn><mspace></mspace><mi>Hz</mi></mrow></math></span>. The fluids used in the experiments were hydrocarbon gas, hydrocarbon liquid and brine at 100 bar and 70 C. A novel analytical approach was developed for analysing the X-ray time series of the local phase fractions over the pipe cross section. The experimental data included a range of water cuts and mixture velocities at 1-degree and 10-degree inclinations in a 3-inch ID pipe. Attention was given to the effects of the fraction of water on the dispersion levels in slugs flows. The X-ray had 30 vertically aligned detectors which allowed the fluid phase fractions to be quantified in each measurement region. To establish which fluid represents the continuous phase at each measurement region, certain phase inversion criteria were needed. These criteria were applied locally for each measurement detector region. The presence of any remaining phases within the region of a given continuous phase allows the quantification of the local dispersed phase fractions. Using this approach, the gas–liquid interface could be identified where the liquid layer may include significant levels of gas dispersion in the liquid. Gamma densitometers were used to corroborate the X-ray measurements for liquid holdup and to establish characteristic velocities for waves and slugs using cross correlations.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105099"},"PeriodicalIF":3.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137396","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":"Evaluation of turbulent co-flow effects on liquid fuel atomization including spray evolution from a pressure swirl atomizer","authors":"Yaquan Sun ,&nbsp;Chetankumar S. Vegad ,&nbsp;Yongxiang Li ,&nbsp;Bruno Renou ,&nbsp;Kaushal Nishad ,&nbsp;François-Xavier Demoulin ,&nbsp;Weibing Wang ,&nbsp;Christian Hasse ,&nbsp;Amsini Sadiki","doi":"10.1016/j.ijmultiphaseflow.2024.105100","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105100","url":null,"abstract":"<div><div>Optimizing combustion systems is imperative due to current environmental and energy demands. To achieve optimal performance once liquid fuel is used for firing such systems, the liquid fuel atomization process needs to be well controlled as it determines all the subsequent multiphase flow evolution in the system. In pressure swirl atomizers, the atomization process typically relies on the combined effects of turbulent kinetic energy and non-axial kinetic energy of the fuel as it exits the nozzle. Notably, the incorporation of co-flow in the spray burner provides additional energy due to the turbulent co-flow level. In this study, numerical techniques are employed for the first time to assess the impact of varying mass flow rates of turbulent co-flow on in-nozzle flow dynamics, liquid atomization, and subsequent processes of an N-heptane spray jet from a swirl simplex atomizer. Appropriate droplet size and velocity measurements, achieved utilizing Phase Doppler Anemometry (PDA) alongside microscopic shadowgraphy to visualize spray atomization phenomena for a single co-flow mass flow rate value, are used as reference validation data. Numerically, a seamless coupling of the Volume of Fluid method (VOF) and the Lagrangian Particle Tracking (LPT) approach within a Large Eddy Simulation (LES) framework is applied. Prior to any analysis, the consistent agreement observed between simulation results and available experimental findings underscored the effectiveness of the employed approach in accurately predicting and thoroughly exploring the whole phenomena under study. Then, the impact of varying the co-flow mass rate is quantified on the in-nozzle flow-dynamics and the flow field in proximity to the gas–liquid interface. In particular, changes in the primary and secondary breakup, initial and outer spray cone angle are evaluated in terms of liquid fuel sheet thickness, breakup length and Weber number as a function of mass co-flow rates. In the dilute spray region, the effects of different co-flow turbulent conditions on the dispersion of the spray are quantitatively evidenced by means of various spray droplet statistics.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"184 ","pages":"Article 105100"},"PeriodicalIF":3.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137398","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}