Pub Date : 2024-09-28DOI: 10.1016/j.ijmultiphaseflow.2024.105013
Hakim Hamdani , Julien Reveillon , Javier Anez , Benjamin Duret , F.X. Demoulin
Recent hydroelectric power plant safety developments have necessitated detailed studies on dam spillway operations, especially during emergency water discharge scenarios such as overtopping. This paper presents a numerical investigation of a 10-meter high waterfall impinging on a solid plate using two-phase flow models. Our approach integrates a coupled Eulerian–Lagrangian Spray Atomization (ELSA) model with an Interface Capturing Method (ICM) to simulate the complex multiphase flow and atomization processes. Our model proficiently mapped the velocity and turbulence within the pre-impact region. To refine the accuracy of the impact pressures, we isolated this zone and implemented the Injection–Reinjection strategy, a novel numerical procedure for this type of configuration. The study reveals significant insights into the dynamic interactions of water packets with the dam structure, highlighting critical impact pressures that can influence dam stability and integrity. Our results, compared against experimental data, demonstrate the effectiveness of the modeling strategies in predicting the fluid behaviors and the subsequent pressures exerted on structural components.
{"title":"Numerical modeling of the impact of a large scale waterfall on a solid plate","authors":"Hakim Hamdani , Julien Reveillon , Javier Anez , Benjamin Duret , F.X. Demoulin","doi":"10.1016/j.ijmultiphaseflow.2024.105013","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105013","url":null,"abstract":"<div><div>Recent hydroelectric power plant safety developments have necessitated detailed studies on dam spillway operations, especially during emergency water discharge scenarios such as overtopping. This paper presents a numerical investigation of a 10-meter high waterfall impinging on a solid plate using two-phase flow models. Our approach integrates a coupled Eulerian–Lagrangian Spray Atomization (ELSA) model with an Interface Capturing Method (ICM) to simulate the complex multiphase flow and atomization processes. Our model proficiently mapped the velocity and turbulence within the pre-impact region. To refine the accuracy of the impact pressures, we isolated this zone and implemented the <em>Injection–Reinjection</em> strategy, a novel numerical procedure for this type of configuration. The study reveals significant insights into the dynamic interactions of water packets with the dam structure, highlighting critical impact pressures that can influence dam stability and integrity. Our results, compared against experimental data, demonstrate the effectiveness of the modeling strategies in predicting the fluid behaviors and the subsequent pressures exerted on structural components.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105013"},"PeriodicalIF":3.6,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424743","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}
Pub Date : 2024-09-28DOI: 10.1016/j.ijmultiphaseflow.2024.105009
T. Cheng , R. Leibovici , B. Kong , R. van Hout
Primary breakup of a liquid water jet in close-coupled gas atomization (CCGA) was studied using digital inline holography. Different nozzles with constant liquid protrusion length and characterized by three different apex angles, = 14, 24 and 34 were used. Measurements were conducted at two Weber numbers, We = 57.5 and 82.5. At each We, five different momentum flux ratios, , were studied. A detailed analysis of the instantaneous liquid jet interfaces indicated that the “filming” occurred at a lower critical with increasing . Furthermore, with increasing , peak probabilities of interface lengths shifted to larger values while increasing led to increased maximum lengths. Fractal dimensions increased with downstream distance. Distributions of area-based droplet diameters spanned a broad size range up to 3 mm and were well described by least-squares fitted power laws, including an exponential cut-off. The highest number of droplets was generated at = 24 for = 1.67 and 2.40 for We = 57.5 and 82.5, respectively. The percentage of circular droplets (based on a circularity-based threshold) was highest at = 14 and decreased with increasing .
{"title":"Experimental investigation of primary breakup in close-coupled gas atomization","authors":"T. Cheng , R. Leibovici , B. Kong , R. van Hout","doi":"10.1016/j.ijmultiphaseflow.2024.105009","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105009","url":null,"abstract":"<div><div>Primary breakup of a liquid water jet in close-coupled gas atomization (CCGA) was studied using digital inline holography. Different nozzles with constant liquid protrusion length and characterized by three different apex angles, <span><math><mi>θ</mi></math></span> = 14<span><math><msup><mrow></mrow><mrow><mi>o</mi></mrow></msup></math></span>, 24<span><math><msup><mrow></mrow><mrow><mi>o</mi></mrow></msup></math></span> and 34<span><math><msup><mrow></mrow><mrow><mi>o</mi></mrow></msup></math></span> were used. Measurements were conducted at two Weber numbers, We<span><math><msub><mrow></mrow><mrow><mi>g</mi></mrow></msub></math></span> = 57.5 and 82.5. At each We<span><math><msub><mrow></mrow><mrow><mi>g</mi></mrow></msub></math></span>, five different momentum flux ratios, <span><math><mi>M</mi></math></span>, were studied. A detailed analysis of the instantaneous liquid jet interfaces indicated that the “filming” occurred at a lower critical <span><math><mi>M</mi></math></span> with increasing <span><math><mi>θ</mi></math></span>. Furthermore, with increasing <span><math><mi>M</mi></math></span>, peak probabilities of interface lengths shifted to larger values while increasing <span><math><mi>θ</mi></math></span> led to increased maximum lengths. Fractal dimensions increased with downstream distance. Distributions of area-based droplet diameters spanned a broad size range up to 3 mm and were well described by least-squares fitted power laws, including an exponential cut-off. The highest number of droplets was generated at <span><math><mi>θ</mi></math></span> = 24<span><math><msup><mrow></mrow><mrow><mi>o</mi></mrow></msup></math></span> for <span><math><mi>M</mi></math></span> = 1.67 and 2.40 for We<span><math><msub><mrow></mrow><mrow><mi>g</mi></mrow></msub></math></span> = 57.5 and 82.5, respectively. The percentage of circular droplets (based on a circularity-based threshold) was highest at <span><math><mi>θ</mi></math></span> = 14<span><math><msup><mrow></mrow><mrow><mi>o</mi></mrow></msup></math></span> and decreased with increasing <span><math><mi>M</mi></math></span>.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105009"},"PeriodicalIF":3.6,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358387","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}
Pub Date : 2024-09-27DOI: 10.1016/j.ijmultiphaseflow.2024.104999
Simon Holz , Maximilian Coblenz , Rainer Koch , Hans-Jörg Bauer , Oliver Grothe
More realistic droplet starting conditions for Euler–Lagrangian simulations enable e.g. more precise soot prediction in jet engines. Up to now, mainly the droplet size distribution of sprays is considered, but not the multivariate dependence structure of droplet size, starting position and initial velocity. A novel concept for extracting multivariate spray data efficiently from detailed simulations of the atomizing process into high fidelity Euler–Lagrangian simulations of spray combustion is presented in this paper. Therefore, simulations of a prefilming airblast atomizer using the Smoothed Particle Hydrodynamics method are considered. The multivariate dependence structure in the spray is identified using rank transformation. Two models of different nature are proposed which are able to reproduce the multivariate dependence structure. The first model follows a data-driven approach using vine copulas and marginal distributions. In contrast, the second model is based on human knowledge and assumptions enabling deeper insights into the atomization process. Both models demonstrated to reproduce the multivariate character of the spray data effectively. An assessment of their capabilities reveals that the first model might be more suitable for spray data of annular injectors.
{"title":"Two approaches for constructing multivariate injection models for prefilming airblast atomizers","authors":"Simon Holz , Maximilian Coblenz , Rainer Koch , Hans-Jörg Bauer , Oliver Grothe","doi":"10.1016/j.ijmultiphaseflow.2024.104999","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104999","url":null,"abstract":"<div><div>More realistic droplet starting conditions for Euler–Lagrangian simulations enable <em>e.g.</em> more precise soot prediction in jet engines. Up to now, mainly the droplet size distribution of sprays is considered, but not the multivariate dependence structure of droplet size, starting position and initial velocity. A novel concept for extracting multivariate spray data efficiently from detailed simulations of the atomizing process into high fidelity Euler–Lagrangian simulations of spray combustion is presented in this paper. Therefore, simulations of a prefilming airblast atomizer using the Smoothed Particle Hydrodynamics method are considered. The multivariate dependence structure in the spray is identified using rank transformation. Two models of different nature are proposed which are able to reproduce the multivariate dependence structure. The first model follows a data-driven approach using vine copulas and marginal distributions. In contrast, the second model is based on human knowledge and assumptions enabling deeper insights into the atomization process. Both models demonstrated to reproduce the multivariate character of the spray data effectively. An assessment of their capabilities reveals that the first model might be more suitable for spray data of annular injectors.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104999"},"PeriodicalIF":3.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441132","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}
Pub Date : 2024-09-26DOI: 10.1016/j.ijmultiphaseflow.2024.105004
Oliver Tolfts , Alexander Rack , Nathanaël Machicoane
The breakup of a liquid jet by a surrounding high-speed gas jet with different liquid Reynolds numbers and gas Weber numbers was studied using high speed phase-contrast X-ray imaging technique. Focusing on the liquid core, the portion of liquid that is connected to the nozzle, four distinct morphologies were observed and can be associated with changes in the large-scale configurations of the two-phase flow are reported in a phase diagram. Gas-to-liquid kinetic energy balance arguments capture several transitions between the liquid core regimes. The temporal evolution of the center of mass of the liquid core is extracted to quantify its motion, whose statistics can be utilized as a signature to distinguish different regimes. At low to moderate gas Weber numbers, the dynamics are strongly influenced by flapping, while long-time dynamics develop at high Weber numbers, that give way to quasi-periodic motions when swirl is impeded to the gas jet.
利用高速相位对比 X 射线成像技术研究了不同液体雷诺数和气体韦伯数的液体射流被周围高速气体射流击碎的过程。以液体核心（即与喷嘴相连的那部分液体）为重点，观察到了四种不同的形态，并在相图中报告了与两相流大尺度配置变化相关的四种形态。气液动能平衡论证捕捉到了液芯状态之间的几种转变。提取液核质心的时间演化来量化其运动，其统计数据可用作区分不同状态的特征。在低到中等气体韦伯数下，动力学受到拍击的强烈影响，而在高韦伯数下则形成了长时间动力学，当气体射流的漩涡受到阻碍时，这种动力学让位于准周期运动。
{"title":"Morphology and dynamics of the liquid jet in high-speed gas-assisted atomization retrieved through synchrotron-based high-speed X-ray imaging","authors":"Oliver Tolfts , Alexander Rack , Nathanaël Machicoane","doi":"10.1016/j.ijmultiphaseflow.2024.105004","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105004","url":null,"abstract":"<div><div>The breakup of a liquid jet by a surrounding high-speed gas jet with different liquid Reynolds numbers and gas Weber numbers was studied using high speed phase-contrast X-ray imaging technique. Focusing on the liquid core, the portion of liquid that is connected to the nozzle, four distinct morphologies were observed and can be associated with changes in the large-scale configurations of the two-phase flow are reported in a phase diagram. Gas-to-liquid kinetic energy balance arguments capture several transitions between the liquid core regimes. The temporal evolution of the center of mass of the liquid core is extracted to quantify its motion, whose statistics can be utilized as a signature to distinguish different regimes. At low to moderate gas Weber numbers, the dynamics are strongly influenced by flapping, while long-time dynamics develop at high Weber numbers, that give way to quasi-periodic motions when swirl is impeded to the gas jet.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105004"},"PeriodicalIF":3.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326468","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}
Pub Date : 2024-09-25DOI: 10.20882/adicciones.1847
Ana Sánchez-Kuhn, Jorge L Puga, Pilar Flores, Ana María Ruiz-Ruano
Problematic smartphone use (PSU) is an uncontrollable behavior that impedes the ability to stop using it despite potential negative consequences. This excessive behavior has been considered in the research field as a behavioral addiction, as literature has shown common characteristics with behavioral addictions, including its impulsivity-driven factor. However, impulsivity is a multidimensional construct whose specific traits lead differently to each addiction. Hence, the present study aimed to address the different existent PSU profiles depending on their individual impulsivity personality traits. To this end, N = 412 adults (average age 31.91, SD = 11.70, including 108 men and 304 women) were recruited to explore their daily smartphone usage, level of smartphone addiction (SAS-SV) and impulsivity profile across the five impulsivity personality traits (UPPS-P). Cluster analysis revealed the existence of three different profiles: one without PSU; one showing an excessive impulsively but almost no addictive smartphone use, expressing only a loss of control symptomatology; and one showing excessive impulsively but also addictive smartphone patterns, driven mainly by the impulsivity personality traits of negative urgency, positive urgency and lack of premeditation. Therefore, this study showed the impulsivity personality traits that differentiate excessive from addictive smartphone use, which is valuable information for the development of more precise prevention and interventions programs.
{"title":"From non-problematic smartphone use to smartphone addiction: Impulsivity-based profiles.","authors":"Ana Sánchez-Kuhn, Jorge L Puga, Pilar Flores, Ana María Ruiz-Ruano","doi":"10.20882/adicciones.1847","DOIUrl":"10.20882/adicciones.1847","url":null,"abstract":"<p><p>Problematic smartphone use (PSU) is an uncontrollable behavior that impedes the ability to stop using it despite potential negative consequences. This excessive behavior has been considered in the research field as a behavioral addiction, as literature has shown common characteristics with behavioral addictions, including its impulsivity-driven factor. However, impulsivity is a multidimensional construct whose specific traits lead differently to each addiction. Hence, the present study aimed to address the different existent PSU profiles depending on their individual impulsivity personality traits. To this end, N = 412 adults (average age 31.91, SD = 11.70, including 108 men and 304 women) were recruited to explore their daily smartphone usage, level of smartphone addiction (SAS-SV) and impulsivity profile across the five impulsivity personality traits (UPPS-P). Cluster analysis revealed the existence of three different profiles: one without PSU; one showing an excessive impulsively but almost no addictive smartphone use, expressing only a loss of control symptomatology; and one showing excessive impulsively but also addictive smartphone patterns, driven mainly by the impulsivity personality traits of negative urgency, positive urgency and lack of premeditation. Therefore, this study showed the impulsivity personality traits that differentiate excessive from addictive smartphone use, which is valuable information for the development of more precise prevention and interventions programs.</p>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"48 ","pages":"287-298"},"PeriodicalIF":2.2,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41278904","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}
Pub Date : 2024-09-25DOI: 10.1016/j.ijmultiphaseflow.2024.105010
Amgad Salama , Mohamed Zoubeik , Jisheng Kou
The problem of ejection of a droplet from a pore opening into a reservoir appears in many fields including pharmaceutical, food, chemical, and several other industries. In this work, we are interested in investigating the onset of dislodgment of such an emerging droplet. A one-dimensional model is developed that describes the dynamics of this process under quasistatic assumptions. Fluid inertia, the dynamic nature of the contact angle, as well as the entrance and exit hydrodynamic effects are ignored. Fluid inertia may be important at the very early stage of the displacement process, after which its effect diminishes. It is hypothesized that the emerging droplet will dislodge the surface when the two contact lines associated with the two interfaces meet. The forces acting on this system include external pressures, viscous and capillary forces. The flow rate is influenced by the capillary pressure of the emerging nonwetting fluid when the advancing interface reaches the exit of the tube and starts to develop, then by the two interfaces when the wetting fluid starts to displace the wetting one. At the onset of dislodgment, the capillary pressure across the two interfaces equalizes. A computational fluid dynamics (CFD) study has been conducted to confirm the stated hypothesis and to provide a framework for the validation and verification of the developed model. The CFD model depicts the whole spectrum of processes involved from the start of injection of the nonwetting fluid towards the ejection of the droplet. The model, however, only considers the system when the wetting fluid starts to emerge from the exit of the tube into the reservoir. Comparisons between the model and the CFD analysis show a good match, which builds confidence in the modeling approach. Interesting results are obtained, particularly when the interfaces reach the exit of the tube.
{"title":"On the termination of an emerging droplet from a capillary tube over a flat surface by a wetting slug: A one-dimensional quasistatic model and CFD analysis","authors":"Amgad Salama , Mohamed Zoubeik , Jisheng Kou","doi":"10.1016/j.ijmultiphaseflow.2024.105010","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105010","url":null,"abstract":"<div><div>The problem of ejection of a droplet from a pore opening into a reservoir appears in many fields including pharmaceutical, food, chemical, and several other industries. In this work, we are interested in investigating the onset of dislodgment of such an emerging droplet. A one-dimensional model is developed that describes the dynamics of this process under quasistatic assumptions. Fluid inertia, the dynamic nature of the contact angle, as well as the entrance and exit hydrodynamic effects are ignored. Fluid inertia may be important at the very early stage of the displacement process, after which its effect diminishes. It is hypothesized that the emerging droplet will dislodge the surface when the two contact lines associated with the two interfaces meet. The forces acting on this system include external pressures, viscous and capillary forces. The flow rate is influenced by the capillary pressure of the emerging nonwetting fluid when the advancing interface reaches the exit of the tube and starts to develop, then by the two interfaces when the wetting fluid starts to displace the wetting one. At the onset of dislodgment, the capillary pressure across the two interfaces equalizes. A computational fluid dynamics (CFD) study has been conducted to confirm the stated hypothesis and to provide a framework for the validation and verification of the developed model. The CFD model depicts the whole spectrum of processes involved from the start of injection of the nonwetting fluid towards the ejection of the droplet. The model, however, only considers the system when the wetting fluid starts to emerge from the exit of the tube into the reservoir. Comparisons between the model and the CFD analysis show a good match, which builds confidence in the modeling approach. Interesting results are obtained, particularly when the interfaces reach the exit of the tube.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105010"},"PeriodicalIF":3.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424810","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}
Pub Date : 2024-09-21DOI: 10.1016/j.ijmultiphaseflow.2024.105006
Yao Xiao, Zhong Zeng, Liangqi Zhang, Denglong Zhang, Manman Sun
In this manuscript, we unveil an innovative acceleration technique for the simulation of multiphase flows, which builds upon the foundation laid by our previously devised multiphase flow solver. The cornerstone of this method lies in augmenting computational efficiency through the selective updating of variables solely within domains characterized by significant gradients of the phase variable. This tactic diminishes the dimensionality of the system of linear equations, thereby hastening the computational process. To pinpoint the regions warranting focused attention, a judicious criterion is indispensable to strike an optimal balance between efficiency and precision. This criterion affords a marked decrement in computational expenditure while preserving the fidelity of the original methodology. Rigorous validations corroborate that this acceleration mechanism can enhance computational efficiency by a minimum of 49.5% in resolving the phase field equation and by at least 70.2% in the computation of pragmatic two-phase flows, without compromising accuracy. Moreover, the efficacy of this acceleration technique is inversely proportional to the rate of interface evolution, becoming increasingly efficient as the interface evolves more slowly.
{"title":"Accelerated calculation of phase-variable for numerical simulation of multiphase flows","authors":"Yao Xiao, Zhong Zeng, Liangqi Zhang, Denglong Zhang, Manman Sun","doi":"10.1016/j.ijmultiphaseflow.2024.105006","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105006","url":null,"abstract":"<div><div>In this manuscript, we unveil an innovative acceleration technique for the simulation of multiphase flows, which builds upon the foundation laid by our previously devised multiphase flow solver. The cornerstone of this method lies in augmenting computational efficiency through the selective updating of variables solely within domains characterized by significant gradients of the phase variable. This tactic diminishes the dimensionality of the system of linear equations, thereby hastening the computational process. To pinpoint the regions warranting focused attention, a judicious criterion is indispensable to strike an optimal balance between efficiency and precision. This criterion affords a marked decrement in computational expenditure while preserving the fidelity of the original methodology. Rigorous validations corroborate that this acceleration mechanism can enhance computational efficiency by a minimum of 49.5% in resolving the phase field equation and by at least 70.2% in the computation of pragmatic two-phase flows, without compromising accuracy. Moreover, the efficacy of this acceleration technique is inversely proportional to the rate of interface evolution, becoming increasingly efficient as the interface evolves more slowly.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105006"},"PeriodicalIF":3.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323379","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}
Pub Date : 2024-09-21DOI: 10.1016/j.ijmultiphaseflow.2024.105003
A. Yurishchev, N. Brauner, A. Ullmann
Two-phase flow with low liquid loads is common in high-pressure natural gas offshore gathering and transmission pipelines. During gas production slowdowns or shutdowns, an accumulation of liquid in the lower sections of subsea pipelines may occur. This phenomenon is observed in jumpers that connect different units in deep-water subsea gas production facilities. The displacement of the accumulated liquid during production ramp-up induces temporal variations in pressure drop across the jumper and forces on its elbows, resulting in flow-induced vibrations (FIV) that pose potential risks to the structural integrity of the jumper. To bridge the gap between laboratory experiments and field conditions, transient 3D numerical simulations were conducted using the OpenFOAM software. These simulations facilitated the development of a mechanistic model to elucidate the factors contributing to increased pressure and forces during the liquid purging process. The study examined the influence of gas pressure level, pipe diameter, initially accumulated liquid amount, liquid properties, and gas mass flow rate on the transient pressure drop and the forces acting on the jumper's elbows. The critical gas production rate required for complete liquid removal of the accumulated liquid was determined, and scaling rules were proposed to predict the effects of gas pressure and pipe diameter on this critical value. The dominant frequencies of pressure and force fluctuations were identified, with low-pressure systems exhibiting frequencies associated with two-phase flow phenomena and high-pressure systems showing frequencies attributed to acoustic waves.
{"title":"Modeling of high-pressure transient gas-liquid flow in M-shaped jumpers of subsea gas production systems","authors":"A. Yurishchev, N. Brauner, A. Ullmann","doi":"10.1016/j.ijmultiphaseflow.2024.105003","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.105003","url":null,"abstract":"<div><div>Two-phase flow with low liquid loads is common in high-pressure natural gas offshore gathering and transmission pipelines. During gas production slowdowns or shutdowns, an accumulation of liquid in the lower sections of subsea pipelines may occur. This phenomenon is observed in jumpers that connect different units in deep-water subsea gas production facilities. The displacement of the accumulated liquid during production ramp-up induces temporal variations in pressure drop across the jumper and forces on its elbows, resulting in flow-induced vibrations (FIV) that pose potential risks to the structural integrity of the jumper. To bridge the gap between laboratory experiments and field conditions, transient 3D numerical simulations were conducted using the OpenFOAM software. These simulations facilitated the development of a mechanistic model to elucidate the factors contributing to increased pressure and forces during the liquid purging process. The study examined the influence of gas pressure level, pipe diameter, initially accumulated liquid amount, liquid properties, and gas mass flow rate on the transient pressure drop and the forces acting on the jumper's elbows. The critical gas production rate required for complete liquid removal of the accumulated liquid was determined, and scaling rules were proposed to predict the effects of gas pressure and pipe diameter on this critical value. The dominant frequencies of pressure and force fluctuations were identified, with low-pressure systems exhibiting frequencies associated with two-phase flow phenomena and high-pressure systems showing frequencies attributed to acoustic waves.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 105003"},"PeriodicalIF":3.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424742","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}
Pub Date : 2024-09-20DOI: 10.1016/j.ijmultiphaseflow.2024.105000
Amir Loyevsky , Ido Immer , Yuval Dagan
Particle dispersion and erosion play an important role in various engineering applications, particularly in impinging jet flows. This study presents a new Eulerian method for characterizing these phenomena in axisymmetric, laminar, and turbulent jets, impinging and transiently eroding a flat wall. The Eulerian mass and momentum conservation equations are solved assuming a one-way coupling between the flow and the particles. The carrier flow boundary layer velocity profiles in the laminar case are validated with analytical solutions. The particle calculation involves two stages, incident and reflected particles, connected via a restitution model. The reflected particles’ results offer insights into secondary erosion areas but are not used for the main erosion calculations. Subsequently, erosion at the eroded surface is computed using an empirical erosion model, followed by the displacement of computational nodes using the linear-elastic, small-strain deformation equations, all of which are solved transiently. The solutions reveal the spatial particle concentrations and momentum for different Stokes numbers: smaller Stokes particles follow the carrier flow streamlines, medium Stokes particles deviate, forming a W-shaped erosion profile, while the largest Stokes particles create a U-shaped profile. This numerical model offers a computationally efficient framework for CFD-based transient erosion calculation due to its Eulerian implementation.
粒子的分散和侵蚀在各种工程应用中发挥着重要作用，尤其是在冲击射流中。本研究提出了一种新的欧拉方法，用于描述轴对称、层流和湍流射流撞击和瞬时侵蚀平壁时的这些现象。欧拉质量和动量守恒方程的求解假定流动与颗粒之间存在单向耦合。层流情况下的载流边界层速度剖面与分析解进行了验证。粒子计算包括入射粒子和反射粒子两个阶段，通过一个复原模型连接起来。反射粒子的计算结果有助于深入了解二次侵蚀区域，但不用于主要侵蚀计算。随后，利用经验侵蚀模型计算受侵蚀表面的侵蚀情况，然后利用线性弹性小应变变形方程计算计算节点的位移，所有这些都是瞬时求解。求解结果揭示了不同斯托克斯数下的空间粒子浓度和动量：较小的斯托克斯粒子沿载流子流线运动，中等斯托克斯粒子偏离，形成 W 形侵蚀剖面，而最大斯托克斯粒子则形成 U 形剖面。由于采用了欧拉方法，该数值模型为基于 CFD 的瞬态侵蚀计算提供了一个计算高效的框架。
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The enhanced-diffusion characteristics of kerosene jet in supersonic crossflow under different supersonic mainstream and kerosene injection conditions were discussed in this paper. Numerous numerical simulations were conducted under varying shock wave intensities, injection momentum flux ratio conditions based on Euler-Lagrangian method. The influence of low-enthalpy (Tt=300 K) and high-enthalpy (Tt=1680 K) supersonic inflow conditions on kerosene diffusion was also involved. The results indicate that the momentum flux ratio caused by injection and evaporation jointly determines the diffusion ability of kerosene. The increase of injection momentum flux ratio and shock wave intensity promotes both the penetration ability and evaporation gain. However, the relative growth rate of penetration depth decreases, and the relative growth rate of evaporation penetration gain increases. As the jet momentum flow ratio decreases and the shock wave intensity increases, the mixing efficiency and relative growth rate of kerosene increase. A judicious design of injection measures proves to be an effective approach for enhancing the diffusion and mixing of kerosene, which holds significant importance in further enhancing the performance of supersonic combustors.
{"title":"Numerical study on enhanced-diffusion characteristics of kerosene jet in supersonic crossflow","authors":"Guangjun Feng, Junlong Zhang, Qingyuan Deng, Hongchao Qiu, Guowei Luan, Wen Bao","doi":"10.1016/j.ijmultiphaseflow.2024.104983","DOIUrl":"10.1016/j.ijmultiphaseflow.2024.104983","url":null,"abstract":"<div><div>The enhanced-diffusion characteristics of kerosene jet in supersonic crossflow under different supersonic mainstream and kerosene injection conditions were discussed in this paper. Numerous numerical simulations were conducted under varying shock wave intensities, injection momentum flux ratio conditions based on Euler-Lagrangian method. The influence of low-enthalpy (<em>T</em><sub>t</sub>=300 K) and high-enthalpy (<em>T</em><sub>t</sub>=1680 K) supersonic inflow conditions on kerosene diffusion was also involved. The results indicate that the momentum flux ratio caused by injection and evaporation jointly determines the diffusion ability of kerosene. The increase of injection momentum flux ratio and shock wave intensity promotes both the penetration ability and evaporation gain. However, the relative growth rate of penetration depth decreases, and the relative growth rate of evaporation penetration gain increases. As the jet momentum flow ratio decreases and the shock wave intensity increases, the mixing efficiency and relative growth rate of kerosene increase. A judicious design of injection measures proves to be an effective approach for enhancing the diffusion and mixing of kerosene, which holds significant importance in further enhancing the performance of supersonic combustors.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"181 ","pages":"Article 104983"},"PeriodicalIF":3.6,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323380","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}
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