The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Yongjiang Li - One of the best experts on this subject based on the ideXlab platform.
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Analysis of flow and phase interaction characteristics in a gas-liquid two-phase pump
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2018Co-Authors: Wenwu Zhang, Zhiyi Yu, Yongjiang LiAbstract:To analyze the characteristics of internal flow and phase interaction in a gas-liquid two-phase pump, the influence of Inlet Gas Void Fraction (IGVF ), discharge coefficient, and medium viscosity were investigated using medium combinations of air-water and air-crude. Simulations were performed using ANSYS_CFX at different IGVF s and various values of discharge coefficient. Structured grid for the full flow passage was generated using ICEM_CFD and TurboGrid. Under conditions of IGVF = 0% (pure water) and IGVF = 15%, the reliability of numerical method was proved by means of the comparison with the experimental data of external characteristic. The results for air-water combination showed a uniform gas distribution in the inlet pipe, and formation of a stratified structure in the outlet pipe. The gas in impeller gathered at the hub because of the rotation of the impeller, also, the Interphase Forces increased with the increased IGVF . For the two medium combinations, the drag Force was the largest Interphase Force, followed by added mass and lift Forces, and then the turbulent dispersion Force was the least, which can be neglected. Because of the larger viscosity of crude than that of water, the variation trend of Interphase Forces in the impeller is relatively smooth along the flow direction when the medium combination was air-crude.
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study of the gas distribution in a multiphase rotodynamic pump based on Interphase Force analysis
Energies, 2018Co-Authors: Wenwu Zhang, Zhiyi Yu, Muhammad Noaman Zahid, Yongjiang LiAbstract:The performance of multiphase pumps has a remarkable influence on the related industrial application. In order to understand the flow field and gas-liquid phase interaction characteristics of a multiphase rotodynamic pump, detailed numerical analysis of the pump with a medium of air-water combination was carried out for the whole flow passage by means of a structured mesh using ICEM_CFD and TurboGrid. The results for 21% inlet gas void fraction (IGVF = 21%) condition showed that the magnitude ratio of non-drag Forces to drag in impeller and guide vane passages was generally less than 1, whereas it was always less than 0.2 for the magnitude ratio of turbulent dispersion Force to drag. When the IGVF was increased, the variation range of Interphase Forces in the impeller was greater than that in the guide vane. In addition, the gas in the impeller mainly accumulated near the suction surface in the outlet region. Further, with increased IGVF, the degree of aggregation increased as well as the gas inhomogeneity, and consequently the Interphase Forces in the impeller increased. Due to the divergent structure of the guide vane, obvious vortexes emerged at the hub and gradually moved toward the blade pressure surface along the streamwise direction.
Zhiyi Yu - One of the best experts on this subject based on the ideXlab platform.
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Analysis of flow and phase interaction characteristics in a gas-liquid two-phase pump
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2018Co-Authors: Wenwu Zhang, Zhiyi Yu, Yongjiang LiAbstract:To analyze the characteristics of internal flow and phase interaction in a gas-liquid two-phase pump, the influence of Inlet Gas Void Fraction (IGVF ), discharge coefficient, and medium viscosity were investigated using medium combinations of air-water and air-crude. Simulations were performed using ANSYS_CFX at different IGVF s and various values of discharge coefficient. Structured grid for the full flow passage was generated using ICEM_CFD and TurboGrid. Under conditions of IGVF = 0% (pure water) and IGVF = 15%, the reliability of numerical method was proved by means of the comparison with the experimental data of external characteristic. The results for air-water combination showed a uniform gas distribution in the inlet pipe, and formation of a stratified structure in the outlet pipe. The gas in impeller gathered at the hub because of the rotation of the impeller, also, the Interphase Forces increased with the increased IGVF . For the two medium combinations, the drag Force was the largest Interphase Force, followed by added mass and lift Forces, and then the turbulent dispersion Force was the least, which can be neglected. Because of the larger viscosity of crude than that of water, the variation trend of Interphase Forces in the impeller is relatively smooth along the flow direction when the medium combination was air-crude.
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study of the gas distribution in a multiphase rotodynamic pump based on Interphase Force analysis
Energies, 2018Co-Authors: Wenwu Zhang, Zhiyi Yu, Muhammad Noaman Zahid, Yongjiang LiAbstract:The performance of multiphase pumps has a remarkable influence on the related industrial application. In order to understand the flow field and gas-liquid phase interaction characteristics of a multiphase rotodynamic pump, detailed numerical analysis of the pump with a medium of air-water combination was carried out for the whole flow passage by means of a structured mesh using ICEM_CFD and TurboGrid. The results for 21% inlet gas void fraction (IGVF = 21%) condition showed that the magnitude ratio of non-drag Forces to drag in impeller and guide vane passages was generally less than 1, whereas it was always less than 0.2 for the magnitude ratio of turbulent dispersion Force to drag. When the IGVF was increased, the variation range of Interphase Forces in the impeller was greater than that in the guide vane. In addition, the gas in the impeller mainly accumulated near the suction surface in the outlet region. Further, with increased IGVF, the degree of aggregation increased as well as the gas inhomogeneity, and consequently the Interphase Forces in the impeller increased. Due to the divergent structure of the guide vane, obvious vortexes emerged at the hub and gradually moved toward the blade pressure surface along the streamwise direction.
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Interphase Force analysis for air water bubbly flow in a multiphase rotodynamic pump
Engineering Computations, 2015Co-Authors: Zhiyi YuAbstract:Purpose – Interphase Forces between the gas and liquid phases determine many phenomena in bubbly flow. For the Interphase Forces in a multiphase rotodynamic pump, the magnitude analysis was carried out within the framework of two-fluid model. The purpose of this paper is to clarify the relative importance of various Interphase Forces on the mixed transport process, and the findings herein will be a base for the future study on the mechanism of the gas blockage phenomenon, which is the most challenging issue for such pumps. Design/methodology/approach – Four types of Interphase Forces, i.e. drag Force, lift Force, virtual mass Force and turbulent dispersion Force (TDF) were taken into account. By comparing with the experiment in the respect of the head performance, the effectiveness of the numerical model was validated. In conditions of different inlet gas void fractions, bubble diameters and rotational speeds, the magnitude analyses were made for the Interphase Forces. Findings – The results demonstrate t...
Wenwu Zhang - One of the best experts on this subject based on the ideXlab platform.
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Analysis of flow and phase interaction characteristics in a gas-liquid two-phase pump
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2018Co-Authors: Wenwu Zhang, Zhiyi Yu, Yongjiang LiAbstract:To analyze the characteristics of internal flow and phase interaction in a gas-liquid two-phase pump, the influence of Inlet Gas Void Fraction (IGVF ), discharge coefficient, and medium viscosity were investigated using medium combinations of air-water and air-crude. Simulations were performed using ANSYS_CFX at different IGVF s and various values of discharge coefficient. Structured grid for the full flow passage was generated using ICEM_CFD and TurboGrid. Under conditions of IGVF = 0% (pure water) and IGVF = 15%, the reliability of numerical method was proved by means of the comparison with the experimental data of external characteristic. The results for air-water combination showed a uniform gas distribution in the inlet pipe, and formation of a stratified structure in the outlet pipe. The gas in impeller gathered at the hub because of the rotation of the impeller, also, the Interphase Forces increased with the increased IGVF . For the two medium combinations, the drag Force was the largest Interphase Force, followed by added mass and lift Forces, and then the turbulent dispersion Force was the least, which can be neglected. Because of the larger viscosity of crude than that of water, the variation trend of Interphase Forces in the impeller is relatively smooth along the flow direction when the medium combination was air-crude.
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study of the gas distribution in a multiphase rotodynamic pump based on Interphase Force analysis
Energies, 2018Co-Authors: Wenwu Zhang, Zhiyi Yu, Muhammad Noaman Zahid, Yongjiang LiAbstract:The performance of multiphase pumps has a remarkable influence on the related industrial application. In order to understand the flow field and gas-liquid phase interaction characteristics of a multiphase rotodynamic pump, detailed numerical analysis of the pump with a medium of air-water combination was carried out for the whole flow passage by means of a structured mesh using ICEM_CFD and TurboGrid. The results for 21% inlet gas void fraction (IGVF = 21%) condition showed that the magnitude ratio of non-drag Forces to drag in impeller and guide vane passages was generally less than 1, whereas it was always less than 0.2 for the magnitude ratio of turbulent dispersion Force to drag. When the IGVF was increased, the variation range of Interphase Forces in the impeller was greater than that in the guide vane. In addition, the gas in the impeller mainly accumulated near the suction surface in the outlet region. Further, with increased IGVF, the degree of aggregation increased as well as the gas inhomogeneity, and consequently the Interphase Forces in the impeller increased. Due to the divergent structure of the guide vane, obvious vortexes emerged at the hub and gradually moved toward the blade pressure surface along the streamwise direction.
Qinggong Wang - One of the best experts on this subject based on the ideXlab platform.
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computation and validation of the Interphase Force models for bubbly flow
International Journal of Heat and Mass Transfer, 2016Co-Authors: Qinggong WangAbstract:Abstract The Interphase Forces play a crucial role in gas–liquid two-phase flow modeling as they construct the mechanical equilibrium between phases and determine the phase distribution pattern across/along the flow channel. In this work, the predictive features of different correlations for the Interphase Forces were analyzed, and corresponding simulations were conducted to validate the accuracy of each correlation. Three experimental cases with a wide range of bubble Renolds number (Reb) were considered in the modeling validation in order to verify the predictive ability of each model on different bubbly flow regimes. The models differences were clarified. The results showed that there was no standard models that could be universally used for all flow conditions. Selection of the correlations for the drag Force, lift Force and wall lubrication Force should take in account of the bubble regimes and the flow patterns in different Reb ranges. Changes of the turbulence dispersion Force model and the turbulent model showed minor influences on the phase distribution in the simulated results, but variation of the turbulent viscosity model significantly affected the turbulent structure in the gas–liquid flow. The optimal models for different Reb ranges had been determined in the simulated results. Based on the results in this work, a modeling strategy route was finally summarized for easier selection of the Interphase Force models in arranging/optimizing simulations. The strategy route can also be used as the validating steps for new Interphase models proposed for bubbly flows.
Bo Yu - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation on effects of Interphase Force closures on liquid phase turbulence and microbubbles distribution in vertical upward channel bubbly flow
Asia-Pacific Journal of Chemical Engineering, 2012Co-Authors: Mingjun Pang, Bo YuAbstract:Fully understanding mechanisms of the phase distribution and modulations of bubbles on the liquid-phase turbulence is very crucial for practical applications of bubbly flows. In this paper, influences of different Interphase Forces on both of them were widely investigated with an Euler-Lagrange model in a vertical upward channel bubbly flow laden with microbubbles. The flow field was simulated by using direct numerical simulations (DNS), while the bubble dynamics were fully analyzed by integration of Newtonian equations of motion taking into account of four different combinations of Interphase Forces. The phase distribution and turbulence statistics of the liquid phase were comprehensively analyzed for all testing cases. The results show that the local void fraction profiles for different testing cases are different, whereas profiles of the turbulent statistics for all cases have a similar distributing trend with different magnitudes. It can be concluded from the present results that the drag Force, the lift Force, and the added mass Force have a comparatively important influence on the local void fraction profile and the liquid-phase turbulence. In contrast, the influence of the pressure gradient Force seems to be extremely small. 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
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Study on dependence of hydrodynamic characteristics on gravity in a vertical upward channel bubbly flow
Advances in Space Research, 2011Co-Authors: Mingjun Pang, Bo YuAbstract:Abstract Since the bubbly flow has extensive applications in the space field, it is very necessary to comprehend the dependence of hydrodynamic characteristics on gravity. In this paper, the dependence of the microbubble distribution and the liquid turbulence modulation by the microbubbles on gravity was investigated in detail with the Euler–Lagrange method. The liquid Navier–Stokes equation was solved using direct numerical simulations (DNS), and the microbubble motion was tracked with Newtonian motion equation considering drag Force, shear lift Force, added mass Force, pressure gradient Force, and wall lift Force. The coupling between the gas and the liquid phases regarded the Interphase Force as a momentum source term in the momentum equation of the liquid. The results showed that the phase profile and the turbulence modulation by the microbubbles strongly depend on the magnitude of gravity. When the influence of gravity is relatively weak, the microbubbles approximately uniformly disperse in the wide central region of the channel, and the average statistics of the liquid turbulence are almost not influenced due to the addition of the microbubbles. However, when the influence of gravity is comparatively important, the majority of the microbubbles accumulate near the wall of the channel, and the injection of the microbubbles modifies the profiles of the liquid average statistics.
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Numerical investigation on effects of Interphase Force closures on liquid‐phase turbulence and microbubbles distribution in vertical upward channel bubbly flow
Asia-Pacific Journal of Chemical Engineering, 2011Co-Authors: Mingjun Pang, Bo YuAbstract:Fully understanding mechanisms of the phase distribution and modulations of bubbles on the liquid-phase turbulence is very crucial for practical applications of bubbly flows. In this paper, influences of different Interphase Forces on both of them were widely investigated with an Euler-Lagrange model in a vertical upward channel bubbly flow laden with microbubbles. The flow field was simulated by using direct numerical simulations (DNS), while the bubble dynamics were fully analyzed by integration of Newtonian equations of motion taking into account of four different combinations of Interphase Forces. The phase distribution and turbulence statistics of the liquid phase were comprehensively analyzed for all testing cases. The results show that the local void fraction profiles for different testing cases are different, whereas profiles of the turbulent statistics for all cases have a similar distributing trend with different magnitudes. It can be concluded from the present results that the drag Force, the lift Force, and the added mass Force have a comparatively important influence on the local void fraction profile and the liquid-phase turbulence. In contrast, the influence of the pressure gradient Force seems to be extremely small. 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
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Numerical studies on effects of bubbles regular array on the liquid‐phase turbulence
Canadian Journal of Chemical Engineering, 2010Co-Authors: Mingjun Pang, Bo YuAbstract:It is well known that additive drag-reducing methods have broadly developing prospects, so studies on mechanisms of additive drag reduction are very necessary. We hypothesised that the main reason for bubbles induced drag reduction is the modification on liquid-phase turbulence structure by the addition of bubbles, and therefore such modification is the focus of our investigation. In this paper, effects of bubbles on liquid-phase turbulence under the circumstance of regular bubble array were investigated by using Euler–Lagrange two-way numerical simulations. The liquid-phase velocity field was solved by using direct numerical simulations (DNS) in Euler frame of reference, and the bubble motion was tracked by using Newtonian motion equations that took into account interaction Forces including drag Force, shear lift Force, gravity Force, buoyant Force, and inertia Force in Lagrange frame of reference. The coupling between the phases was realised by regarding the Interphase Forces as momentum source terms of the continuous phase. Similarities and differences for effects of bubbles and surfactants on liquid turbulent flows were also analysed. The study indicated that addition of bubbles enhances the mean streamwise velocity, greatly reduces the Reynolds stress, and shows anisotropic suppression to the velocity fluctuations. The Interphase Force has a great influence on budget of energy balance. It is a gain term near the wall and is a loss term in a wide range of the channel core.
