Pub Date : 2025-04-02DOI: 10.1016/j.ijmultiphaseflow.2025.105225
Yanzhi Zhang, Chentao Chu, Zihe Liu, Ming Jia
The use of liquid ammonia as fuel in energy conversion devices presents attractive prospects due to its advantage of zero carbon dioxide emissions. However, the dynamics, atomization, and phase change behaviors of liquid ammonia spray are significantly different from those of conventional gasoline and diesel fuels because of its unique physical properties (e.g., low boiling point, low viscosity, and high latent heat of vaporization), making an accurate simulation of liquid ammonia spray under a wide range of ambient conditions highly challenging. To address this, improved drag, atomization, and vaporization sub-models are proposed in this study to more precisely simulate the ammonia spray process. The effects of finite viscosity and droplet distortion (ranging from prolate spheroid to oblate spheroid) are considered to replicate the drag and vaporization characteristics of ammonia spray. Additionally, an updated flash-boiling atomization model is introduced to reproduce the thermal breakup process by introducing the influence of liquid viscosity in the breakup dispersion equation. The bubble growth rate within the liquid droplet is also enhanced using the latest theories. The validity of the improved models is evaluated through comparisons of experiments and large-eddy simulation (LES) of ammonia spray under typical evaporating and flash-boiling conditions. It is found that the new drag model predicts a lower drag coefficient and a higher evaporation rate than the traditional model under the evaporating conditions and can more accurately reproduce the experimental data. Moreover, the improved flash-boiling atomization model, coupled with the new drag model, demonstrates the highest accuracy in predicting spray dynamics and morphology of flash-boiling sprays compared to other models. After extensive validations, the improved spray models can effectively reproduce the atomization and vaporization characteristics of liquid ammonia sprays across a wide range of operating conditions.
{"title":"Improved dynamics, atomization, and vaporization models for liquid ammonia spray simulations under diverse ambient conditions","authors":"Yanzhi Zhang, Chentao Chu, Zihe Liu, Ming Jia","doi":"10.1016/j.ijmultiphaseflow.2025.105225","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105225","url":null,"abstract":"<div><div>The use of liquid ammonia as fuel in energy conversion devices presents attractive prospects due to its advantage of zero carbon dioxide emissions. However, the dynamics, atomization, and phase change behaviors of liquid ammonia spray are significantly different from those of conventional gasoline and diesel fuels because of its unique physical properties (e.g., low boiling point, low viscosity, and high latent heat of vaporization), making an accurate simulation of liquid ammonia spray under a wide range of ambient conditions highly challenging. To address this, improved drag, atomization, and vaporization sub-models are proposed in this study to more precisely simulate the ammonia spray process. The effects of finite viscosity and droplet distortion (ranging from prolate spheroid to oblate spheroid) are considered to replicate the drag and vaporization characteristics of ammonia spray. Additionally, an updated flash-boiling atomization model is introduced to reproduce the thermal breakup process by introducing the influence of liquid viscosity in the breakup dispersion equation. The bubble growth rate within the liquid droplet is also enhanced using the latest theories. The validity of the improved models is evaluated through comparisons of experiments and large-eddy simulation (LES) of ammonia spray under typical evaporating and flash-boiling conditions. It is found that the new drag model predicts a lower drag coefficient and a higher evaporation rate than the traditional model under the evaporating conditions and can more accurately reproduce the experimental data. Moreover, the improved flash-boiling atomization model, coupled with the new drag model, demonstrates the highest accuracy in predicting spray dynamics and morphology of flash-boiling sprays compared to other models. After extensive validations, the improved spray models can effectively reproduce the atomization and vaporization characteristics of liquid ammonia sprays across a wide range of operating conditions.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105225"},"PeriodicalIF":3.6,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785202","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 : 2025-04-01DOI: 10.1016/j.ijmultiphaseflow.2025.105237
Pakorn Wongpromma, Somchai Wongwises
Flow boiling experiments with refrigerants flowing through a multiple microchannel heat exchanger were performed to investigate the resulting flow patterns and heat transfer characteristics. Data were obtained from experiments on saturation flow boiling of R-513A and R-134a flowing through a multiple microchannel heat exchanger with a 655 µm microchannel hydraulic diameter. The test section consisted of 27 microchannels with 300 µm between the top of the fin and a cover plate. Each microchannel was 382 μm wide and 470 μm deep, with a 416 μm fin thickness. The experiments were conducted on refrigerants in horizontal flow at a constant 28°C saturation temperature, with mass fluxes ranging from 200 kg/m2s to 1200 kg/m2s and applied heat fluxes between 10 kW/m2-400 kW/m2. Flow visualization was illustrated by using a high-speed camera to observe the flow phenomena and the transition behavior of flow patterns in the microchannels. The results show that the heat transfer coefficient (HTC) of R-513A increases with the heat flux, but decreases with mass flux, while the HTC of R-134a increases with both heat and mass flux. R-134a presents the higher values of HTC in comparison to those of R-513A. Additionally, new correlations were developed and proposed based on these experimental data. The experimental results were also compared to correlations previously reported in the literature.
{"title":"Flow patterns and heat transfer characteristics in flow boiling of R-513A and R-134a refrigerant in open microchannel heat sinks","authors":"Pakorn Wongpromma, Somchai Wongwises","doi":"10.1016/j.ijmultiphaseflow.2025.105237","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105237","url":null,"abstract":"<div><div>Flow boiling experiments with refrigerants flowing through a multiple microchannel heat exchanger were performed to investigate the resulting flow patterns and heat transfer characteristics. Data were obtained from experiments on saturation flow boiling of R-513A and R-134a flowing through a multiple microchannel heat exchanger with a 655 µm microchannel hydraulic diameter. The test section consisted of 27 microchannels with 300 µm between the top of the fin and a cover plate. Each microchannel was 382 μm wide and 470 μm deep, with a 416 μm fin thickness. The experiments were conducted on refrigerants in horizontal flow at a constant 28°C saturation temperature, with mass fluxes ranging from 200 kg/m<sup>2</sup>s to 1200 kg/m<sup>2</sup>s and applied heat fluxes between 10 kW/m<sup>2</sup>-400 kW/m<sup>2</sup>. Flow visualization was illustrated by using a high-speed camera to observe the flow phenomena and the transition behavior of flow patterns in the microchannels. The results show that the heat transfer coefficient (HTC) of R-513A increases with the heat flux, but decreases with mass flux, while the HTC of R-134a increases with both heat and mass flux. R-134a presents the higher values of HTC in comparison to those of R-513A. Additionally, new correlations were developed and proposed based on these experimental data. The experimental results were also compared to correlations previously reported in the literature.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"189 ","pages":"Article 105237"},"PeriodicalIF":3.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816216","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 : 2025-03-31DOI: 10.1016/j.ijmultiphaseflow.2025.105235
Hongchao Miao , Lin Mu , Hongchao Yin , Ming Dong , Yan Shang , Da Zhang , Hang Pu
A unified algorithm was developed to numerically investigate the effects of surface curvature on particle deposition and heat exchange performance in turbulent flow. The hybrid approach integrates the interpolation-supplemented thermal lattice Boltzmann method for solving the thermal fluid field on a non-uniform mesh, the immersed boundary method for handling fluid–cylinder interface deformation, and the discrete phase model for determining particle dynamic behavior. The capabilities of the proposed model for predicting deposition characteristics were validated. Systematic simulations were conducted by varying the inlet velocity from 3 to 7 m·s–1 and the Stokes number from 0.023 to 0.061 at variable curvature surfaces (lrh = 0.6–1.4). As lrh increased from 0.6 to 1.4, the deposition layer area and average Nusselt number decreased by 38.66 % and 17.1 %, respectively. Elevating lrh is conducive to reducing deposition with an inconspicuous loss in heat exchanger efficiency. The proportion of deposited particles with high kinetic energy and low impact angle increased during the late deposition period. As the inlet velocity increased, the low lrh surface exhibited higher deposition augmentation and stronger heat transfer enhancement. Elevating lrh can significantly alleviate the deposition of small and medium Stp particles while exerting inconspicuous effects on larger Stp particles.
{"title":"A numerical study on micron particle deposition of variable curvature surfaces using IBM-thermal ISLBM","authors":"Hongchao Miao , Lin Mu , Hongchao Yin , Ming Dong , Yan Shang , Da Zhang , Hang Pu","doi":"10.1016/j.ijmultiphaseflow.2025.105235","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105235","url":null,"abstract":"<div><div>A unified algorithm was developed to numerically investigate the effects of surface curvature on particle deposition and heat exchange performance in turbulent flow. The hybrid approach integrates the interpolation-supplemented thermal lattice Boltzmann method for solving the thermal fluid field on a non-uniform mesh, the immersed boundary method for handling fluid–cylinder interface deformation, and the discrete phase model for determining particle dynamic behavior. The capabilities of the proposed model for predicting deposition characteristics were validated. Systematic simulations were conducted by varying the inlet velocity from 3 to 7 m·s<sup>–1</sup> and the Stokes number from 0.023 to 0.061 at variable curvature surfaces (<em>l<sub>rh</sub></em> = 0.6–1.4). As <em>l<sub>rh</sub></em> increased from 0.6 to 1.4, the deposition layer area and average Nusselt number decreased by 38.66 % and 17.1 %, respectively. Elevating <em>l<sub>rh</sub></em> is conducive to reducing deposition with an inconspicuous loss in heat exchanger efficiency. The proportion of deposited particles with high kinetic energy and low impact angle increased during the late deposition period. As the inlet velocity increased, the low <em>l<sub>rh</sub></em> surface exhibited higher deposition augmentation and stronger heat transfer enhancement. Elevating <em>l<sub>rh</sub></em> can significantly alleviate the deposition of small and medium <em>St<sub>p</sub></em> particles while exerting inconspicuous effects on larger <em>St<sub>p</sub></em> particles.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105235"},"PeriodicalIF":3.6,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785199","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}
The aggregation of molten particles in flash smelting furnaces has become a growing concern as feed rates increase, necessitating a deeper understanding to enable practical adjustments. This study presents a coupled CFD‒PBM approach to investigate the gas–particle reactive flow and particle aggregation within the furnace. Based on experimental data, a temperature-based aggregation kernel is developed and integrated into the PBM to characterize particle evolution. The simulations are validated against experimental data, demonstrating reasonable agreement in terms of particle distributed radius and growth rate. Furthermore, the effects of airflow momentum ratio and injected particle size on particle evolution are analyzed. The results reveal that the high-temperature region, generated by the exothermic oxidation of sulfides, begins at the mid-height of the reaction shaft. Within this region, molten particles aggregate and grow to over twice the injected size. Increasing the airflow momentum ratio enhances particle ignition and oxidation, and greater particle dispersion reduces collisions and aggregation. Larger injected particle sizes also decrease aggregation but may delay the particle ignition and oxidation in the middle of the reaction shaft. However, the oxidation rates of larger particles remain comparable upon reaching the settler. These findings suggest that increasing the airflow momentum ratio and the injected particle size improves production efficiency, presenting a practical strategy for optimizing FSF operations.
{"title":"CFD‒PBM modeling of gas‒particle reactive flow and particle aggregation in the flash smelting furnace","authors":"Zhenyu Zhu , Ping Zhou , Wenke Tan , Zhuo Chen , Shibo Kuang","doi":"10.1016/j.ijmultiphaseflow.2025.105233","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105233","url":null,"abstract":"<div><div>The aggregation of molten particles in flash smelting furnaces has become a growing concern as feed rates increase, necessitating a deeper understanding to enable practical adjustments. This study presents a coupled CFD‒PBM approach to investigate the gas–particle reactive flow and particle aggregation within the furnace. Based on experimental data, a temperature-based aggregation kernel is developed and integrated into the PBM to characterize particle evolution. The simulations are validated against experimental data, demonstrating reasonable agreement in terms of particle distributed radius and growth rate. Furthermore, the effects of airflow momentum ratio and injected particle size on particle evolution are analyzed. The results reveal that the high-temperature region, generated by the exothermic oxidation of sulfides, begins at the mid-height of the reaction shaft. Within this region, molten particles aggregate and grow to over twice the injected size. Increasing the airflow momentum ratio enhances particle ignition and oxidation, and greater particle dispersion reduces collisions and aggregation. Larger injected particle sizes also decrease aggregation but may delay the particle ignition and oxidation in the middle of the reaction shaft. However, the oxidation rates of larger particles remain comparable upon reaching the settler. These findings suggest that increasing the airflow momentum ratio and the injected particle size improves production efficiency, presenting a practical strategy for optimizing FSF operations.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105233"},"PeriodicalIF":3.6,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785200","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 : 2025-03-26DOI: 10.1016/j.ijmultiphaseflow.2025.105228
Xin Zhang , Jianxin Shi , Baozhi Sun , Wanze Wu , Pingtuan Wang
A numerical model is developed using the interIsoFoam solver within the OpenFOAM-v2106 framework to investigate gas-liquid two-phase annular flow in inclined tubes, with a specific focus on upward flow at five different inclination angles. The tube, which is 700 mm long with an inner diameter of 11.7 mm. The working fluid consists of air and water at atmospheric pressure, with the gas phase exhibiting a superficial velocity of 18 m/s, and the liquid film characterized by a liquid film Reynolds number (Ref) of 350. Near the inlet, high-frequency, low-amplitude initial waves are present. As the flow develops, these waves evolve into slower ripples at the top of the tube, particularly in the horizontal tube. Meanwhile, at the bottom, they transition into high-amplitude disturbance waves. This progression reflects the distinct evolution of wave types at the top and bottom as the flow progresses. The base liquid film thickness and interfacial wave amplitude in the inclined tube exhibit pronounced circumferential non-uniformity, with both decreasing gradually from the top to the bottom. This non-uniformity becomes more pronounced as the inclination angle decreases. An edge detection algorithm is used to identify the characteristic lines of ripple and disturbance waves, aiding in the investigation of circumferential wave velocity variations within the tube.
{"title":"Simulations for the interfacial waves in air-water annular flow in upward inclined tubes","authors":"Xin Zhang , Jianxin Shi , Baozhi Sun , Wanze Wu , Pingtuan Wang","doi":"10.1016/j.ijmultiphaseflow.2025.105228","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105228","url":null,"abstract":"<div><div>A numerical model is developed using the <em>interIsoFoam</em> solver within the OpenFOAM-v2106 framework to investigate gas-liquid two-phase annular flow in inclined tubes, with a specific focus on upward flow at five different inclination angles. The tube, which is 700 mm long with an inner diameter of 11.7 mm. The working fluid consists of air and water at atmospheric pressure, with the gas phase exhibiting a superficial velocity of 18 m/s, and the liquid film characterized by a liquid film Reynolds number (<em>Re<sub>f</sub></em>) of 350. Near the inlet, high-frequency, low-amplitude initial waves are present. As the flow develops, these waves evolve into slower ripples at the top of the tube, particularly in the horizontal tube. Meanwhile, at the bottom, they transition into high-amplitude disturbance waves. This progression reflects the distinct evolution of wave types at the top and bottom as the flow progresses. The base liquid film thickness and interfacial wave amplitude in the inclined tube exhibit pronounced circumferential non-uniformity, with both decreasing gradually from the top to the bottom. This non-uniformity becomes more pronounced as the inclination angle decreases. An edge detection algorithm is used to identify the characteristic lines of ripple and disturbance waves, aiding in the investigation of circumferential wave velocity variations within the tube.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105228"},"PeriodicalIF":3.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143767760","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 : 2025-03-25DOI: 10.1016/j.ijmultiphaseflow.2025.105229
Xinran Ye , Zan Wu , Haiou Wang , Jianren Fan , Kun Luo
Microreactors have been widely applied in various fields involving gas-liquid two-phase reactions. However, there is still a need to achieve stable and high conversion rates in microreactors because the complex interactions between the gas and liquid phases can lead to unstable flow patterns, resulting in inefficient mass transport and reduced conversion rates. This work designs a novel radial channel microreactor for hydrogen peroxide decomposition. By integrating fast Fourier transform (FFT) and wavelet transform (WT) methods for time-frequency analysis with visual experiments, this study reveals the impact of reactant flow rate and concentration on flow instability, as well as flow pattern transitions. The radial channel reactor attains a conversion level that remains unaffected by variations in reactant flow rate by employing periodic flow pattern transitions when using 3 wt.% H₂O₂. In the case with 10 wt.% and the case with 30 wt.% H2O2, the radial channel reactor can stabilize the flow pattern transition to achieve a high conversion. The highest conversion rate for H2O2 decomposition is 92.7 % in the case with 30 wt.% H2O2, surpassing the previously reported values in the literature. Through multiple linear regression (MLR) method, a predictive model is proposed and helps to elucidate the effects of reactant flow rate and concentration. This work proves an improved reactor design to utilize and alleviate two-phase flow instability can enhance reactor performance and achieve high conversion rates.
{"title":"High-efficiency microreactor design for hydrogen peroxide decomposition: impact of concentration and flow rate on two-phase flow instability and conversion","authors":"Xinran Ye , Zan Wu , Haiou Wang , Jianren Fan , Kun Luo","doi":"10.1016/j.ijmultiphaseflow.2025.105229","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105229","url":null,"abstract":"<div><div>Microreactors have been widely applied in various fields involving gas-liquid two-phase reactions. However, there is still a need to achieve stable and high conversion rates in microreactors because the complex interactions between the gas and liquid phases can lead to unstable flow patterns, resulting in inefficient mass transport and reduced conversion rates. This work designs a novel radial channel microreactor for hydrogen peroxide decomposition. By integrating fast Fourier transform (FFT) and wavelet transform (WT) methods for time-frequency analysis with visual experiments, this study reveals the impact of reactant flow rate and concentration on flow instability, as well as flow pattern transitions. The radial channel reactor attains a conversion level that remains unaffected by variations in reactant flow rate by employing periodic flow pattern transitions when using 3 wt.% H₂O₂. In the case with 10 wt.% and the case with 30 wt.% H<sub>2</sub>O<sub>2</sub>, the radial channel reactor can stabilize the flow pattern transition to achieve a high conversion. The highest conversion rate for H<sub>2</sub>O<sub>2</sub> decomposition is 92.7 % in the case with 30 wt.% H<sub>2</sub>O<sub>2</sub>, surpassing the previously reported values in the literature. Through multiple linear regression (MLR) method, a predictive model is proposed and helps to elucidate the effects of reactant flow rate and concentration. This work proves an improved reactor design to utilize and alleviate two-phase flow instability can enhance reactor performance and achieve high conversion rates.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105229"},"PeriodicalIF":3.6,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724102","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 : 2025-03-23DOI: 10.1016/j.ijmultiphaseflow.2025.105226
Mukhtiar Ahmed , Yang Yang , Xiaoxing Liu
This study investigates the hydrodynamic behavior of fluid-particle interactions in fixed bed assemblies containing particles of various shapes, including spheres, cylinders, and trilobes. Using sequential rigid body dynamics (RBD) for particle-resolved computational fluid dynamics (PRCFD) simulations, we analysed local flow structures in random packings of these particles. The simulations were efficiently conducted for systems containing 120 to 700 particles. We also examined the influence of the tube-to-particle diameter ratio (N) to understand the wall effects on packing and flow structure. Our analyses of porosity, flow behavior, and pressure drop align well with established empirical correlations. The results indicated that local structural configurations significantly affect velocity distribution at the particle level. The RBD-CFD method employed in this study proves to be a robust and reliable tool for obtaining detailed insights into particle-level hydrodynamics in fixed bed reactors with both spherical and non-spherical particles.
{"title":"Particle-resolved simulation of flow and hydrodynamic behavior of different shape particles in fixed bed reactor","authors":"Mukhtiar Ahmed , Yang Yang , Xiaoxing Liu","doi":"10.1016/j.ijmultiphaseflow.2025.105226","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105226","url":null,"abstract":"<div><div>This study investigates the hydrodynamic behavior of fluid-particle interactions in fixed bed assemblies containing particles of various shapes, including spheres, cylinders, and trilobes. Using sequential rigid body dynamics (RBD) for particle-resolved computational fluid dynamics (PRCFD) simulations, we analysed local flow structures in random packings of these particles. The simulations were efficiently conducted for systems containing 120 to 700 particles. We also examined the influence of the tube-to-particle diameter ratio (N) to understand the wall effects on packing and flow structure. Our analyses of porosity, flow behavior, and pressure drop align well with established empirical correlations. The results indicated that local structural configurations significantly affect velocity distribution at the particle level. The RBD-CFD method employed in this study proves to be a robust and reliable tool for obtaining detailed insights into particle-level hydrodynamics in fixed bed reactors with both spherical and non-spherical particles.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105226"},"PeriodicalIF":3.6,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785201","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}
We experimentally and numerically investigated the interaction between a spark-induced bubble and an elastic plate. We focused on the bubble dynamics and plate deformation, which influenced by different boundary thickness h ( h ) and initial stand-off distance (). The elastic plate is made of carbon fiber layers, attached to a gum base of 0.1 mm thickness. A transient cavitation bubble generated by the fast electric discharge between two immersed electrodes, and the bubble maximum radius is 20 mm. We used high-speed camera to capture the bubble motion and the boundary motion at the simultaneously. We also conducted numerical simulations with the immersed boundary method, taking into account fluid compressibility and the boundary motion. The research results demonstrate that the amplitude of plate deformation directly affects the dynamic behavior of the bubble. The plate deformation along vertical direction is periodic in time, and the difference between the free end and the center () is almost an approximate wave function. A dimensionless parameter is proposed to measure the frequency and amplitude of boundary oscillations. The trend of over time satisfies the wave equation, which shows that the plate undergoes a similar harmonic vibration after the force is applied. The function can be viewed as a superposition of an external force (from the flow field) induced oscillation () and a self-inertial oscillation (). We found that increasing the initial distance mainly reduces the maximum amplitude of the external force-induced oscillation . Increasing the plate thickness h results in a reduction of both the frequency and amplitude of the oscillation function. Some of the conclusions of this work can be applied to the design of new hydromechanics of materials.
{"title":"On the interaction of a cavitation bubble with an carbon fiber composite elastic plate","authors":"Lei Han, Jiacheng Chen, Ruiquan Zhou, Mindi Zhang, Biao Huang, CLEO Collaboration","doi":"10.1016/j.ijmultiphaseflow.2025.105203","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105203","url":null,"abstract":"<div><div>We experimentally and numerically investigated the interaction between a spark-induced bubble and an elastic plate. We focused on the bubble dynamics and plate deformation, which influenced by different boundary thickness <em>h</em> (<span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn><mo><</mo></mrow></math></span> <em>h</em> <span><math><mrow><mo><</mo><mn>2</mn><mo>.</mo><mn>0</mn><mspace></mspace><mi>mm</mi></mrow></math></span>) and initial stand-off distance <span><math><mi>γ</mi></math></span> (<span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn><mo><</mo><mi>γ</mi><mo><</mo><mn>2</mn><mo>.</mo><mn>0</mn></mrow></math></span>). The elastic plate is made of carbon fiber layers, attached to a gum base of 0.1 mm thickness. A transient cavitation bubble generated by the fast electric discharge between two immersed electrodes, and the bubble maximum radius is 20 mm. We used high-speed camera to capture the bubble motion and the boundary motion at the simultaneously. We also conducted numerical simulations with the immersed boundary method, taking into account fluid compressibility and the boundary motion. The research results demonstrate that the amplitude of plate deformation directly affects the dynamic behavior of the bubble. The plate deformation along vertical direction is periodic in time, and the difference between the free end and the center (<span><math><mi>λ</mi></math></span>) is almost an approximate wave function. A dimensionless parameter <span><math><mrow><mi>Δ</mi><mi>ζ</mi></mrow></math></span> is proposed to measure the frequency and amplitude of boundary oscillations. The trend of <span><math><mrow><mi>Δ</mi><mi>ζ</mi><mrow><mo>(</mo><mi>t</mi><mo>)</mo></mrow></mrow></math></span> over time satisfies the wave equation, which shows that the plate undergoes a similar harmonic vibration after the force is applied. The function can be viewed as a superposition of an external force (from the flow field) induced oscillation (<span><math><msub><mrow><mi>ζ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>) and a self-inertial oscillation (<span><math><msub><mrow><mi>ζ</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>). We found that increasing the initial distance <span><math><mi>γ</mi></math></span> mainly reduces the maximum amplitude of the external force-induced oscillation <span><math><msub><mrow><mi>ζ</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>. Increasing the plate thickness <em>h</em> results in a reduction of both the frequency and amplitude of the oscillation function. Some of the conclusions of this work can be applied to the design of new hydromechanics of materials.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105203"},"PeriodicalIF":3.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682040","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 : 2025-03-19DOI: 10.1016/j.ijmultiphaseflow.2025.105221
Najeeb Anjum Soomro
<div><div>This research provides new insights into foam-enhanced oil recovery (EOR) by using advanced X-ray CT imaging to reveal foam displacement mechanisms in porous media. It highlights the superior stability and efficiency of nitrogen foam over CO₂ foam, offering practical guidelines to optimize EOR operations in heterogeneous and gravity-affected reservoirs. Due to its superior mobility control and sweep efficiency compared to other injection methods like gas flooding, water flooding, and other EOR techniques, foam-enhanced oil recovery, or EOR, has been used as an improved recovery method. High-viscosity foam shows significant potential for liquid displacement. Foam's relative immobility in porous media appears to more stable displacement prevent fingers from forming during oil displacement, which results in a more stable displacement. Nevertheless, several factors, including the characteristics of the oil, the permeability of the rock in the reservoir, the chemical and physical makeup of the foam, and others, could potentially affect how effective foam assisted oil displacement is. Furthermore, it is yet unclear how the foam interacts with and moves within the porous environment. Therefore, using a porous media setup with gases, water, surfactant, and foam injection, we examined oil recovery three-dimensional (3D) properties in this work. The patterns of fluid displacement were recorded and examined using a CT scanning scanner. Additionally, the impact of oil viscosity on patterns of foam displacement is investigated. The study offers a quantitative and qualitative experimental visualization of liquid and foam injection, oil recovery with gases, and 3D displacement structures. Consequently, foam injection exhibits good sweeping ability and produces a stable displacement front, as demonstrated by comparing fluid displacement patterns between gases, water, surfactant, and foam. Oil displacement was enhanced by the synergistic action of the surfactant, liquid, and gas components that combine to form foam. On the other hand, investigations with gas flooding and liquid flooding demonstrate trapped oil, gravity segregation, and viscous fingering. The foam that produced the best oil recovery factor displaced steadily across the permeable bed. This work clarified the mechanism of foam movement in porous media. When foam comes into contact with oil and porous medium, it bursts into free-moving liquid and gas particles. As a result, the foam injection experiment revealed two displacement fronts: the continuously flowing gas/liquid layer in front, which moves forward in contact with the oil bank, and the steadily flowing foam bank in the rear. Oil viscosity has no discernible effect on foam displacement because of the foam bank's stable displacement, which also means that there is no difference in the displacement patterns. Although the displaced oil has varying viscosities, the flow regimes remain consistent. A linear link has not been demonstrated
{"title":"Three-dimensional display of foam-driven oil displacement in porous materials","authors":"Najeeb Anjum Soomro","doi":"10.1016/j.ijmultiphaseflow.2025.105221","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105221","url":null,"abstract":"<div><div>This research provides new insights into foam-enhanced oil recovery (EOR) by using advanced X-ray CT imaging to reveal foam displacement mechanisms in porous media. It highlights the superior stability and efficiency of nitrogen foam over CO₂ foam, offering practical guidelines to optimize EOR operations in heterogeneous and gravity-affected reservoirs. Due to its superior mobility control and sweep efficiency compared to other injection methods like gas flooding, water flooding, and other EOR techniques, foam-enhanced oil recovery, or EOR, has been used as an improved recovery method. High-viscosity foam shows significant potential for liquid displacement. Foam's relative immobility in porous media appears to more stable displacement prevent fingers from forming during oil displacement, which results in a more stable displacement. Nevertheless, several factors, including the characteristics of the oil, the permeability of the rock in the reservoir, the chemical and physical makeup of the foam, and others, could potentially affect how effective foam assisted oil displacement is. Furthermore, it is yet unclear how the foam interacts with and moves within the porous environment. Therefore, using a porous media setup with gases, water, surfactant, and foam injection, we examined oil recovery three-dimensional (3D) properties in this work. The patterns of fluid displacement were recorded and examined using a CT scanning scanner. Additionally, the impact of oil viscosity on patterns of foam displacement is investigated. The study offers a quantitative and qualitative experimental visualization of liquid and foam injection, oil recovery with gases, and 3D displacement structures. Consequently, foam injection exhibits good sweeping ability and produces a stable displacement front, as demonstrated by comparing fluid displacement patterns between gases, water, surfactant, and foam. Oil displacement was enhanced by the synergistic action of the surfactant, liquid, and gas components that combine to form foam. On the other hand, investigations with gas flooding and liquid flooding demonstrate trapped oil, gravity segregation, and viscous fingering. The foam that produced the best oil recovery factor displaced steadily across the permeable bed. This work clarified the mechanism of foam movement in porous media. When foam comes into contact with oil and porous medium, it bursts into free-moving liquid and gas particles. As a result, the foam injection experiment revealed two displacement fronts: the continuously flowing gas/liquid layer in front, which moves forward in contact with the oil bank, and the steadily flowing foam bank in the rear. Oil viscosity has no discernible effect on foam displacement because of the foam bank's stable displacement, which also means that there is no difference in the displacement patterns. Although the displaced oil has varying viscosities, the flow regimes remain consistent. A linear link has not been demonstrated ","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105221"},"PeriodicalIF":3.6,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704788","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 : 2025-03-19DOI: 10.1016/j.ijmultiphaseflow.2025.105222
George H. Downing, Yannis Hardalupas
Understanding the preferential concentration of inertial particles in turbulent flows is crucial for a wide range of natural and industrial processes. This study advances our understanding of turbulence-particle interactions by systematically evaluating the combined effects of turbulent Reynolds number (Reλ), Stokes number (Stk), and Froude number (Fr) on particle clustering through direct numerical simulations (DNS). Our analysis demonstrates that particle clustering intensity peaks at Stk ∼ 1, where particles optimally interact with turbulent eddies. While previous research often overlooks the influence of Reynolds number, our findings reveal that this assumption holds for small Stk, but for larger Stk, Reynolds number significantly impacts clustering behaviour. Gravitational effects, quantified by Fr, also play a critical role in clustering dynamics. For Stk << 1, gravity's impact is minimal for Fr < 5.0; however, as Stk increases, gravity enhances large-scale clustering and modulates small-scale clustering—diminishing it for intermediate Stk ∼ 1 and enhancing it for Stk >> 1. Here, large-scale clustering refers to particle clustering at scales comparable to the largest energy-containing eddies, while small-scale clustering involves particle clustering at the dissipative scales of turbulence. We introduce a novel empirical model that predicts particle concentration spectra within 12 % relative error across a wide range of conditions validated against current and previous studies. This model provides a practical tool for analysing particle-laden turbulent flows in large spaces and has substantial implications for atmospheric science, chemical engineering, and environmental studies, offering improved predictions of droplet clustering in clouds, particulate dispersion in reactors, and pollutant transport.
{"title":"Spectral analysis of preferential concentration in turbulent flows: parametric dependence on Reynolds, stokes, and froude numbers","authors":"George H. Downing, Yannis Hardalupas","doi":"10.1016/j.ijmultiphaseflow.2025.105222","DOIUrl":"10.1016/j.ijmultiphaseflow.2025.105222","url":null,"abstract":"<div><div>Understanding the preferential concentration of inertial particles in turbulent flows is crucial for a wide range of natural and industrial processes. This study advances our understanding of turbulence-particle interactions by systematically evaluating the combined effects of turbulent Reynolds number (Re<sub>λ</sub>), Stokes number (Stk), and Froude number (Fr) on particle clustering through direct numerical simulations (DNS). Our analysis demonstrates that particle clustering intensity peaks at Stk ∼ 1, where particles optimally interact with turbulent eddies. While previous research often overlooks the influence of Reynolds number, our findings reveal that this assumption holds for small Stk, but for larger Stk, Reynolds number significantly impacts clustering behaviour. Gravitational effects, quantified by Fr, also play a critical role in clustering dynamics. For Stk << 1, gravity's impact is minimal for Fr < 5.0; however, as Stk increases, gravity enhances large-scale clustering and modulates small-scale clustering—diminishing it for intermediate Stk ∼ 1 and enhancing it for Stk >> 1. Here, large-scale clustering refers to particle clustering at scales comparable to the largest energy-containing eddies, while small-scale clustering involves particle clustering at the dissipative scales of turbulence. We introduce a novel empirical model that predicts particle concentration spectra within 12 % relative error across a wide range of conditions <span><math><mrow><mo>(</mo><mrow><mn>0.1</mn><mo>≤</mo><mspace></mspace><mi>S</mi><mi>t</mi><mi>k</mi><mo>≤</mo><mspace></mspace><mn>5.0</mn><mo>;</mo><mspace></mspace><mn>57</mn><mo>≤</mo><mspace></mspace><mi>R</mi><mi>e</mi><mo>≤</mo><mspace></mspace><mn>111</mn><mo>;</mo><mspace></mspace><mn>0.0</mn><mo>≤</mo><mspace></mspace><mi>F</mi><mi>r</mi><mo>≤</mo><mspace></mspace><mn>5.0</mn></mrow><mo>)</mo><mo>,</mo><mspace></mspace></mrow></math></span>validated against current and previous studies. This model provides a practical tool for analysing particle-laden turbulent flows in large spaces and has substantial implications for atmospheric science, chemical engineering, and environmental studies, offering improved predictions of droplet clustering in clouds, particulate dispersion in reactors, and pollutant transport.</div></div>","PeriodicalId":339,"journal":{"name":"International Journal of Multiphase Flow","volume":"188 ","pages":"Article 105222"},"PeriodicalIF":3.6,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682038","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}
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