Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics最新文献

{"title":"Water-Oil Flow in Square Microchannels With a Crossed Junction","authors":"Z. Cao, Zan Wu, J. Qian, B. Sundén","doi":"10.1115/FEDSM2018-83056","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83056","url":null,"abstract":"In the present study, water-oil flow patterns and slug hydrodynamics were experimentally studied in square glass microchannels with various hydraulic diameters (Dh = 600 μm, 400 μm, 200 μm). The aqueous phase is the continuous phase while the organic phase is the dispersed phase. The ranges of flow rates of the continuous phase and the dispersed phase are 0–200 ml/h and 0–12 ml/h, 0–120 ml/h and 0–6 ml/h, and 0–60 ml/h and 0–2 ml/h in the microchannels with Dh = 600 μm, 400 μm and 200 μm, respectively. The results show that the hydraulic diameter has significant effects on flow patterns and three main flow patterns are observed, i.e., annular flow, slug flow and droplet flow. Generally, annular flow appeared at high flow rates of the dispersed phase and low flow rates of the continuous phase, while droplet flow appeared at low flow rates of the dispersed phase and high flow rates of the continuous phase. However, slug flow existed at comparable flow rates of the continuous and dispersed phases. A dimensionless analysis is carried out and a new dimensionless group including Weber number and Reynolds number is derived. The new defined dimensionless group performs well to develop a general flow pattern map. In addition, slug flow hydrodynamics are investigated as well in the present study, considering the slug length and slug velocity. Based on the present experimental results, a new scaling law is proposed to predict the slug length and it shows a good agreement with the experimental results. It has been widely reported that slug velocities depend linearly on the total flow rates of the two phases, which is consistent with the present study. The linear law provides a good prediction of the experimental slug velocities but different slopes are suggested in microchannels with different hydraulic diameters.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116983039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Experimental, Thermoelastohydrodynamic (TEHD) and Isothermal, Non-Deforming Computational Fluid Dynamics (CFD) Results for Thrust Bearings","authors":"Xin Deng, Cori Watson, M. He, H. Wood, R. Fittro","doi":"10.1115/FEDSM2018-83177","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83177","url":null,"abstract":"Bearings are machine elements that allow components to move with respect to each other. A thrust bearing is a particular type of rotary bearing permitting rotation between parts but designed to support a predominately axial load. Oil-lubricated bearings are widely used in high speed rotating machines such as those found in the aerospace and automotive industries. With the increase of velocity, the lubrication regime will go through boundary lubrication, mixed lubrication, and hydrodynamic lubrication (full film). In this paper, the analysis was in the hydrodynamic lubrication region.\u0000 THRUST is used to predict the steady-state operating characteristics of oil-lubricated thrust bearings. As a thermoelastohydrodynamic prediction tool, THRUST assumes a 3D turbulence model, 3D energy equation, and 2D Reynolds equation. Turbulence is included by obtaining average values of eddy momentum flux (Reynolds stress) and averaging the influence down to a 2D Reynolds equation. Convergence is achieved by iterating on the pad tilt angles and pivot film thickness until the integrated pressure matches the load applied to the pad. Despite the multiple experimental, CFD, and TEHD studies of thrust bearings that have been performed to date, no validation has yet been performed to confirm the accuracy of TEHD methods in modeling the performance of thrust bearings by both experimental and advanced computational means simultaneously. This study addresses this need by comparing TEHD and CFD simulation results of film thickness, temperature, power loss, and pressure in thrust bearings taken from the literature at multiple speeds and loads with results from experimental data.\u0000 Starting from the case of the lowest speed and load, it was verified that this case is indeed laminar and with negligible thermal and elastic effects. Four cases were run in THRUST, a TEHD solver, combining thermal and deformation in each rotational speed and load combination. Additionally, a CFD study was performed in ANSYS CFX with the assumptions of isothermal, non-deforming. The average viscosity from THRUST was used in CFD to follow the effects of the isoviscous assumption. Then, the experimental, TEHD and CFD results were compared at each case. Experimental, TEHD, and CFD results show acceptable agreement when turbulence is negligible.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127250142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strength Analysis of PV Components on Solar Tanker Based on Fluid-Structure Interaction","authors":"Zhang Dongxu, L. Hong, Xu Fangfang","doi":"10.1115/FEDSM2018-83433","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83433","url":null,"abstract":"Solar energy, as a major source of clean energy, has gradually been applied in ship industry, but it has rarely been used in large transport vessels. This paper takes VLCC (Very Large Crude Carrier) as the study object and presents a design scheme of PV (photovoltaic) modules and their supports on the deck of an oil carrier. In accordance with current ship norms and standards, the rocking inertia force and wind pressures acting on both the PV modules and the supports at different wind velocities are computed using the finite element software of Ansys and Fluent, and the simulated wind pressures are compared to the formula-based calculation results. Stress and displacement of the supporting leg in marine environment are calculated and the supports is structurally optimized as well. In the end, a simulation method for checking the strength of the solar-powered oil carrier is presented, and the scheme of adding a knee plate to decrease stress concentration at the intersection of the three tubes of the leg is proposed.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115108616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Development of an Ultra Low Head Axial Hydro Turbine for Electricity Supply: Part II","authors":"Jinbo Chen, A. Engeda","doi":"10.1115/fedsm2018-83016","DOIUrl":"https://doi.org/10.1115/fedsm2018-83016","url":null,"abstract":"As a major resource for electricity, hydropower is widely used around the world for renewable energy. Traditionally, large high-capital cost dam equipped with large turbine system is preferred to produce sufficient power supply. However, recently large hydropower system is questioned because of the impact of dams on the local environment, which could be a major barrier for development of large hydropower system. Besides, billions people remain without access to electricity and most of them are in remote and rural location where is not suitable for large hydropower system. Therefore, the utilization of ultra-low-head (ULH) water energy (situations where the hydraulic head is less than 3m or the water flow rate is more than 0.5m/s with zero head) has becomes more attractive. Part I of this paper focus on developing a design methodology for a low-impact, damless Kaplan turbine system for ULH water resource. Part II of this paper focus on providing detailed CFD simulations to demonstrate that this methodology is valid and effective.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122143453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Numerical and Experimental Investigation Into Hydraulic Characteristics of a No-Load Running Check Valve due to Fluid-Structure Interaction","authors":"Xiang-Yuan Zhang, Zhijun Shuai, Chenxing Jiang, Wanyou Li, J. Jian","doi":"10.1115/FEDSM2018-83524","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83524","url":null,"abstract":"Valve is a very important unit in pipeline system. The valve flow fluctuation brings about structural vibration and unpopular noise, and even leads to the safety problems and disasters. In this paper, a special no-load running check valve is investigated. The check valve is structural complex with one inlet and two outlets. It can be simplified as a spring-mass system which manipulates the flow rate by combine action of the ambient pressure of medium and the spring deformation.\u0000 The three-dimensional model of the valve is established and also the relationship between pressure drops and flow rate of the valve is obtained in various openings and operating conditions. The structure modals were verified by the field tests and thus its fixing boundaries are obtained correctly.\u0000 The mechanism causing self-excited vibration of a piping system is determined using a dynamic model which couples the hydraulics of internal flow with the structural motion of a three-ports passive check valve. The coupling is obtained by making the fluid flow coefficient at the check valve to be a function of valve plug displacement. The results are compared with the experimental data, which verifies the correctness of the theoretical results.\u0000 It is shown that the special valve has its own hydraulic characteristics, which greatly influence its flow distribution as it has two outlets. It was also testified that the coupling between fluid and structure changes its natural frequencies and has a non-negligible impact on the pressure fluctuation while working.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117101736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Wettability on Capillary Flow of Non-Newtonian Fluid in Microchannels","authors":"Kiarash Keshmiri, Neda Nazemifard, Haibo Huang","doi":"10.1115/FEDSM2018-83533","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83533","url":null,"abstract":"In this study, capillary filling of diluted bitumen was evaluated using glass etched microchannel. Glass microchannel was treated using Trichloro(1H,1H,2H,2H-perfluorooctyl) silane that makes the microchannel lyophobic (not favorable for neither hydrophilic nor hydrophobic liquids). Water contact angle, as a degree of hydrophilicity, was changed from 15° for untreated microchannel to 115° for treated microchannel. Measured Capillary filling speed of bitumen in hexane (10% to 60%) was experimentally monitored using white light microscope and compared with Washburn theoretical model. For all samples, a linear relation between square of propagation distance and time was found. However, a deviation between experimental and theoretical values of penetration as a function of time was recorded. Experimental results indicated slower velocity compared to theoretical prediction due to simplifications of the Washburn model. Advancing dynamic contact angle of capillary-driven flow was measured and compared with static contact angle using MATLAB®. It was found that dynamic contact angle was increasing during the penetration in microchannel and application of a constant contact angle leads to higher deviation between experimental and theoretical results.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129772421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Interaction Between Tip Leakage Flow Generated by Unshrouded Impeller and Diffuser Internal Flow","authors":"Asuma Ichinose, N. Kimura, M. Yoshimura, Tomoyuki Hayashi, K. Miyagawa","doi":"10.1115/FEDSM2018-83502","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83502","url":null,"abstract":"Rocket turbo pumps and industrial pumps such as water feed pumps are required to work under high pressure conditions, therefore low specific speed pumps are needed in spite of high rotational speed. In recent years, unshrouded impellers were used because of easy manufacturing and cost reduction. However, when low specific speed unshrouded impellers are used in such conditions, complex tip leakage flow occur and decrease impeller performance. In addition, splitter blades are often used, the internal flow becomes even more complicated. Therefore, such the internal flow of the unshrouded impeller must be clarified. In this research, we have studied such a centrifugal pump, and we have analyzed the internal flow using experiments and CFD (Computational Fluid Dynamics) simulations.\u0000 The experimental verification was carried out by measuring the total pressure distribution on the outlet of the impeller and the diffuser. The unsteady static pressure distribution at the shroud side of the impeller was measured to confirm pump performance. We used two types of CFD simulation to evaluate the internal flow in detail. In the first CFD simulation, the unsteady internal flow of an impeller was evaluated by carrying out DES (Detached Eddy Simulation) with a periodic boundary condition that does not contain the diffuser. In the second CFD simulation, interaction between the impeller leakage flow and the diffuser internal flow was evaluated by DES with the whole impeller and diffuser.\u0000 From the experimental verification and CFD simulation, it was confirmed that a large-scale vortex structure caused by the tip leakage flow and the secondary flow was observed in the impeller blade-to-blade. And the influence of the impeller leakage flow on the diffuser internal flow and the diffuser performance was evaluated.\u0000 From the above studies, it was confirmed that the tip leakage flow has a large influence on the impeller internal flow and the diffuser performance.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123961236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-Plane Hydraulic Resistance Through Paper-Thin Porous Media","authors":"S. Doser, Sang Joon John Lee","doi":"10.1115/FEDSM2018-83262","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83262","url":null,"abstract":"This work investigates the special case of in-plane fluid flow of a Newtonian incompressible fluid at low Reynolds numbers across a paper-thin porous medium in a confined conduit. Fluid transport in sheets with these characteristics are used in emerging devices such as microscale paper-based analytical devices (μPADs) and “e-paper” displays. Darcy’s law is applied and tested to determine if experimentally measured pressures at two flow rates of 5 μL/min and 10 μL/min agree with predicted values. A test device was designed using kinematic design principles to ensure a deterministic 318 μm gap that directs prescribed flow, unidirectionally across porous filter paper. The paper used was Grade 50 Whatman filter paper with an average pore size of 2.7 μm. Pressure was measured along the direction of flow over a 125 mm distance by six pressure ports placed at uniform increments of 25 mm to determine a profile of pressure along the flow path. Measurements were recorded at discrete time intervals over a period up to 48 hours with at least four replicates. Experimental measurements of the pressure profile show a linear relationship as predicted by Darcy’s law, allowing material permeability to be calculated. Among replicates measured under the same set of controllable conditions, experimental data also show a nonlinear relationship. The nonlinearity suggests evidence of transition into an inertia region, providing insight into the factors and behavior of the Darcy-Forchheimer transition for this special case of porous media flow.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132485166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Unsteady Flow in a Submersible Tubular Pumping System","authors":"Yan Jin, Hongcheng Chen, D. Ting, Jacqueline A. Stagner, Junxin Wu, Chao Liu","doi":"10.1115/FEDSM2018-83062","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83062","url":null,"abstract":"To better understand the workings of submersible tubular pumping system and to enable future improvements, the pressure fluctuation and unsteady flow characteristics due to the complex rotor-stator interactions need to be properly delineated. High-frequency pressure measurements coupled with CFD simulations have been invoked in this study to elucidate the unsteady flow in different components of a submersible tubular pumping system at different discharges. The focus is on the impeller and guide vane, where the unsteady interaction is the strongest. The pressure pulsation distributions of different characteristic cross sections such as impeller exit, middle of guide vane, and exit of guide vane were quantified. In addition, the flow characteristics and the turbulent kinetic energy inside the impeller, guide vane, and bulb unit were obtained at the different time steps. The results show that the pressure pulsation frequency obtained by simulation was in agreement with the experimental results, including the critical points around the impeller and the guide vanes. The complementary two-prong approach is thus proven to be a powerful duo in researching and advancing a convoluted pumping system.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133590483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and Numerical Analyses of Unsteady Flow Regimes and Mixing in a Micro T-Mixer","authors":"M. Salvetti, A. Mariotti, C. Galletti, E. Brunazzi","doi":"10.1115/FEDSM2018-83459","DOIUrl":"https://doi.org/10.1115/FEDSM2018-83459","url":null,"abstract":"Despite the very simple geometry, T-shaped micro-mixers are characterized by different and complex laminar flow regimes. In the present work, experiments and direct numerical simulations are employed jointly to investigate unsteady periodic flow regimes, viz. the asymmetric and symmetric regimes. The first is characterized by a periodic dynamics of the three-dimensional structures and by a high degree of mixing, while in the second the flow always maintains a double mirror symmetry in the mixing channel, which causes a dramatic decrease of the mixing performance. A methodology, allowing us to quantitatively compare the numerical predictions with experimental flow visualizations, is used to investigate these unsteady regimes and to evaluate the relevant frequencies and the degree of mixing. In both regimes the characteristic non-dimensional frequency, based on the bulk velocity and hydraulic diameter of the mixing channel, increases with the Reynolds number, but a significant discontinuity is found at the transition from the first to the second regime.","PeriodicalId":285631,"journal":{"name":"Volume 3: Fluid Machinery; Erosion, Slurry, Sedimentation; Experimental, Multiscale, and Numerical Methods for Multiphase Flows; Gas-Liquid, Gas-Solid, and Liquid-Solid Flows; Performance of Multiphase Flow Systems; Micro/Nano-Fluidics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131664400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}