Flow, Turbulence and Combustion最新文献

{"title":"Effect of Low Pressure on Flame Propagation of Hydrogen-Kerosene-Air Mixture","authors":"Jian Liu,&nbsp;Yafen Wang,&nbsp;Lingyun Hou,&nbsp;Xinyan Pei","doi":"10.1007/s10494-024-00630-7","DOIUrl":"10.1007/s10494-024-00630-7","url":null,"abstract":"<div><p>Hydrogen may play an important role in gas turbine engines for achieving carbon neutrality and performing high-altitude missions. Hydrogen influence on the flame speed of aviation kerosene at low pressures was investigated using a constant-volume bomb. The laminar flame speed of aviation kerosene at atmospheric pressure exhibited a linear relationship with increasing hydrogen mass fraction, with a more pronounced promoting effect under fuel-rich conditions. Hydrogen promotion effects on normalized kerosene laminar flame speed are weaker at low pressures than those at atmospheric pressures. The addition of hydrogen and low pressure suppresses flame instability of aviation kerosene especially under fuel-rich conditions, thereby reducing the promoting effect of turbulence on fuel-rich flame propagation. A scaling law that accounted for the influence of flame stability was successfully constructed to characterize the turbulent flame speed of hydrogen-rich aviation kerosene under different conditions.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 4","pages":"1297 - 1314"},"PeriodicalIF":2.0,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards LES of Liquid Jet Atomization Using an Eulerian-Lagrangian Multiscale Approach","authors":"Elias Trautner,&nbsp;Josef Hasslberger,&nbsp;Markus Klein","doi":"10.1007/s10494-024-00620-9","DOIUrl":"10.1007/s10494-024-00620-9","url":null,"abstract":"<div><p>This study is concerned with Large Eddy Simulation of liquid jet atomization using a two-way coupled Eulerian-Lagrangian multiscale approach. The proposed framework combines Volume-of-Fluid interface capturing with Lagrangian Particle Tracking. The former is used to compute the core jet and large liquid elements in the near-nozzle region, whereas the latter is used to track the large number of small droplets in the dilute downstream region of the spray. The convective and surface tension sub-grid scale terms arising in the context of two-phase flow LES are closed using suitable models, and secondary atomization is considered by employing a modified version of the Taylor Analogy Breakup model. The introduced framework is used to simulate an oil-in-air atomization as well as the Diesel-like Spray A test case of the Engine Combustion Network. Compared to previous studies based on Eulerian-Lagrangian methods, the present work stands out for the high-fidelity numerical approach, the complex test cases and the detailed comparison of the results to experimental data, which indicates a promising performance.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"115 Simulation and Measurements","pages":"243 - 273"},"PeriodicalIF":2.0,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-024-00620-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Blowout and Blowoff Limits of Confined Coaxial Ammonia/Hydrogen/Nitrogen-Air Flames with Variable Ammonia Fraction","authors":"Rajneesh Yadav,&nbsp;R. Santhosh","doi":"10.1007/s10494-024-00624-5","DOIUrl":"10.1007/s10494-024-00624-5","url":null,"abstract":"<div><p>The present experimental study reports first observations of stability, blowout, and blowoff characteristics of ammonia–hydrogen–nitrogen fuel blend flames with varying volumetric ammonia fractions (<span>({x}_{{NH}_{3}})</span>) in a coaxial combustor. The <span>({x}_{{NH}_{3}})</span> is varied from 20 to 80%. For flames of ammonia fraction equal to 70% (<span>({x}_{{NH}_{3}}=0.7)</span>), three types of flame transitions are observed within fuel flow Reynolds number (<span>({Re}_{f})</span>) of 40–575 as a coflow Reynolds number (<span>({Re}_{a})</span>) is increased in steps. Initially, the coflow air remains laminar and <span>({Re}_{a})</span> is increased gradually from laminar to turbulent limit. Different flame stabilization modes are characterized as burner-attached and lifted flame. The flame extinction modes are classified as <i>lifted-blowoff</i>, <i>attached-blowoff</i> and <i>attached-blowout</i> types. These flame transitions and stabilization characteristics are shown to be similar to methane flames. However, the <i>flame height</i> and <i>liftoff height</i> are shown to be different. The flames of fuel blends with ammonia fraction less than or equal to 60% (<span>({x}_{{NH}_{3}}le 0.6)</span>) are shown to behave fundamentally different from that of flames with <span>({x}_{{NH}_{3}}&gt;0.6)</span> (and also methane flames). Specifically, within the tested <span>({Re}_{f})</span> range, only one type of flame transition is observed as <span>({Re}_{a})</span> is systematically varied in the former as compared to three types observed in the latter. Also, with a decrease in ammonia fraction (and a corresponding increase in hydrogen percentage), the <i>liftoff limit</i>, <i>reattachment limit</i>, and <i>blowout limits</i> all are observed to increase. The effect of ammonia composition on <i>flame height</i> and <i>liftoff height</i> is also elaborated. The present study also provides empirical correlations (particularly for the low power flames) for predicting <i>blowout</i> and <i>blowoff limits</i> in both lifted and attached conditions for ammonia-hydrogen–nitrogen fuel blend flames.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 2","pages":"527 - 560"},"PeriodicalIF":2.0,"publicationDate":"2024-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Different Throttle Openings on Multi-plane Analysis of In-cylinder Flow Fields in a Small-Bore Spark-Ignition Engine","authors":"Kartheeswaran Ayyanar,&nbsp;Soumyanil Nayek,&nbsp;T. N. C. Anand,&nbsp;Mayank Mittal","doi":"10.1007/s10494-024-00628-1","DOIUrl":"10.1007/s10494-024-00628-1","url":null,"abstract":"<div><p>To meet stringent emission norms and achieve enhanced engine performance in spark-ignition engines, in-cylinder charge motion is one of the most important factors for fuel–air mixture preparation and proper combustion. However, in small-bore spark-ignition engines, the development of tumble motion is hindered by an anticlockwise vortex located beneath the intake valve, leading to an early tumble decay during compression. Moreover, the intensity of the tumble directly depends on the intake mass flow rate, regulated by throttle valve openings. Therefore, understanding the impact of throttle openings on flow evolution in small-bore engines is essential. This study employs computational fluid dynamics (CFD) simulations, validated against experimental data of in-cylinder pressure traces and ensemble-averaged flow fields, to analyze the influence of throttle openings on flow fields. Flow evolution on multiple planes is discussed in-depth, along with the jet emanating from the intake valve curtain area, which is correlated with the formation of in-cylinder flow structures. Additionally, it is found that both intake mass flow rate and backflow intensity significantly affect the flow fields. While backflow during intake valve opening (IVO) is more pronounced under 25% throttle opening (TO) condition, it minimally impacts the flow fields on the symmetric tumble plane during the intake stroke for both the TO conditions. Conversely, backflow during intake valve closing (IVC) is more prominent under 100% TO, resulting in earlier tumble decay compared to 25% TO. Also, the effect of backflow is found to have minimal effects on the flow fields of the cross-tumble plane and offset tumble plane.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 4","pages":"1233 - 1267"},"PeriodicalIF":2.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of Energetic Low Dimensional Subspaces in Spatio-Temporal Space in Turbulent Pipe Flow","authors":"Amir Shahirpour,&nbsp;Christoph Egbers,&nbsp;Jörn Sesterhenn","doi":"10.1007/s10494-024-00600-z","DOIUrl":"10.1007/s10494-024-00600-z","url":null,"abstract":"<div><p>Low dimensional subspaces are extracted out of highly complex turbulent pipe flow at <span>(Re_{tau }=181)</span> using a Characteristic Dynamic Mode Decomposition (CDMD). Having lower degrees of freedom, the subspaces provide a more clear basis to detect events which meet our understanding of large-scale coherent structures. To this end, a temporal sequence of state vectors from direct numerical simulations are rotated in space-time such that persistent dynamical modes on a hyper-surface are found travelling along its normal in space-time, which serves as the new time-like coordinate. The main flow features are captured with a minimal number of modes on a moving frame of reference whose velocity matches that of the most energetic scale. Reconstruction of the candidate modes in physical space gives the low rank model of the flow. The structures living in this subspace have long lifetimes, posses wide range of length-scales and travel at group velocities close to that of the moving frame of reference. The modes within this subspace are highly aligned, but are separated from the remaining modes by larger angles. We are able to capture the essential features of the flow like the spectral energy distribution and Reynolds stresses with a subspace consisting of about 10 modes. The remaining modes are collected in two further subspaces, which distinguish themselves by their axial length scale and degree of isotropy.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 Heat and Mass Transfer","pages":"1017 - 1041"},"PeriodicalIF":2.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-024-00600-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of LES-ADM Accuracy for Modelling of Auto-Ignition and Flame Propagation in a Temporally-Evolving Nitrogen-Diluted Hydrogen Jet","authors":"Lena Caban,&nbsp;Artur Tyliszczak,&nbsp;Bernard J. Geurts,&nbsp;Julian A. Domaradzki","doi":"10.1007/s10494-024-00613-8","DOIUrl":"10.1007/s10494-024-00613-8","url":null,"abstract":"<div><p>The aim of the research is to analyze the accuracy of the approximate deconvolution method (ADM) for large eddy simulation (LES) modelling of auto-ignition and flame propagation in a turbulent, temporally-evolving nitrogen-diluted hydrogen jet. In ADM, filtered chemical reaction terms are not modelled; instead, they are directly computed based on deconvolved scalar variables, approximately inverting the spatial LES filter. The deconvolution process employs an iterative van Cittert method based on an assumed filter function. The study assesses the dependence of ADM accuracy on various filter types, such as Gaussian and finite/compact difference filters, used both as the LES filter (<span>({mathcal {G}}_Delta)</span>) and the filter for deconvolution (<span>({mathcal {G}}_E)</span>). The results obtained with ADM are compared with those obtained from the Eulerian stochastic field (ESF) combustion model, the laminar chemistry model (LCM) - a ’no-model’ approach, and direct numerical simulation (DNS). Particular attention is given to situations in which the filter <span>({mathcal {G}}_E)</span> differs from <span>({mathcal {G}}_Delta)</span>, whose explicit form is generally unknown in LES. It is shown that LES-ADM performs similarly to the LES-ESF model and, in general yields better results than obtained with LES-LCM. However, in certain combinations of the <span>({mathcal {G}}_E)</span> and <span>({mathcal {G}}_Delta)</span> filters, the results of simulations are worse than those using LES-LCM and sometimes even unstable. The reasons for such behaviour of the ADM method are identified, explained in 1D <i>a priori</i> tests, and then confirmed in 3D LES. It is shown that when the filter <span>({mathcal {G}}_E)</span> is of a higher order than <span>({mathcal {G}}_Delta)</span> (<span>({mathcal {O}}{({mathcal {G}}_E)}&gt;{mathcal {O}}({mathcal {G}}_Delta ))</span>) or it has a transfer function close to one over a wide range of wave numbers, the energy at small scales of the deconvolved variables is attenuated. Conversely, if the opposite situation takes place (<span>({mathcal {O}}{({mathcal {G}}_E)}&lt;{mathcal {O}}({mathcal {G}}_Delta ))</span>), the small scale’s energy is amplified. Moreover, in this case, the apparent improvement in deconvolution accuracy by increasing the number of van Cittert iterations actually worsens the results and can lead to instability.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"115 Simulation and Measurements","pages":"303 - 345"},"PeriodicalIF":2.0,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical and Experimental Study on the Deflagration Characteristics of Premixed CO in a Tube with Obstacles","authors":"Qingqing Chen,&nbsp;Teng Li,&nbsp;Yao Wang,&nbsp;Xiaolin Wei,&nbsp;Liang Zhang","doi":"10.1007/s10494-024-00627-2","DOIUrl":"10.1007/s10494-024-00627-2","url":null,"abstract":"<div><p>As the main by-product of converter steelmaking process, converter gas has significant potential for energy recovery due to its high calorific value. However, there is a significant risk of explosion during the recycling process. In order to ensure the process safety of converter gas recovery and achieve efficient energy utilization, it is necessary to study the process of CO deflagration in the tube and prevent it. This article combines experiments and numerical simulations to study the effects of obstacles inside tube, water content in the air, and the length of the smooth section on CO deflagration characteristics. The results show that the propagation characteristics of flames in the smooth section are related to the flow field and have periodicity. The length of the smooth section does not significantly affect the maximum deflagration pressure. During the propagation of flames in the obstacle section, the acceleration effect of each obstacle on the flame is similar, and the deflagration becomes more and more intense as the number of obstacles increases. The peak value is reached at the last obstacle, about 0.72 MPa, and the flame speed can reach 672 m/s. The water content in the air has a significant impact on the maximum deflagration pressure of CO, as H₂O triggers a series of chain branching reactions. When the water content increases to 0.39%, the maximum deflagration pressure reaches its peak. In terms of numerical simulation, the reliability of the open-source combustion solver XiFoam was verified. The combustion, transport, and thermodynamic property parameters for premixed gas of CO and humid air were provided using Cantera. Finally, in order to avoid the occurrence of deflagration during the converter gas recovery process, it is necessary to strictly control its moisture content.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 2","pages":"561 - 583"},"PeriodicalIF":2.0,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Eddy Simulation and Turbulence Model Assessment of Buoyant Flow in a Thermal Energy Storage Tank","authors":"Xiaowei Xu,&nbsp;Ali Haghiri,&nbsp;Richard Sandberg,&nbsp;Yicheng Cao,&nbsp;Takuo Oda,&nbsp;Koichi Tanimoto","doi":"10.1007/s10494-024-00611-w","DOIUrl":"10.1007/s10494-024-00611-w","url":null,"abstract":"<div><p>Single-medium thermal energy storage is widely used for heat and cooling supply. During the charging and discharging process via jet nozzles, strong transient turbulent mixing and heat transfer occurs. Hence, qualitative and quantitative understanding on the thermal mixing mechanisms are beneficial to the design and operation of the thermal storage system. In this study, we perform large eddy simulation (LES) of a three-dimensional stratified water storage tank with a single jet issuing hot water to study the long-time behaviour. The simulation data are utilised to investigate the flow and thermal characteristics of the tank, especially the formation of the buoyant jet and the thermal dispersion along the vertical direction. It is shown that the fine vortical jet shear-layer structures are responsible for most of the turbulence mixing. Furthermore, the LES results are regarded as reference data for assessing the flow predictions that result from different solver set-ups and turbulence models employed in unsteady Reynolds averaged Navier–Stokes (URANS) calculations. The results demonstrate that the realisable <span>(k-varepsilon )</span> model can yield satisfactory predictive accuracy, once the buoyant production is correctly included in both transport equations. Finally, we examine the effect of different choices of turbulence heat flux models, including the standard/generalised gradient diffusion hypothesis (SGDH and GGDH) and algebraic heat flux model (AFM), on the numerical predictions. The results indicate that the URANS with GGDH and AFM can accurately and efficiently predict the flow and thermal fields in the turbulent flow regime.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"115 Simulation and Measurements","pages":"169 - 192"},"PeriodicalIF":2.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relation Between 3 and 2D Wrinkling Factors in Turbulent Premixed Flames","authors":"Markus Klein,&nbsp;Nilanjan Chakraborty","doi":"10.1007/s10494-024-00622-7","DOIUrl":"10.1007/s10494-024-00622-7","url":null,"abstract":"<div><p>The magnitude of the wrinkled flame surface area in turbulent premixed flames divided by its projection in the direction of flame propagation, known as the wrinkling factor, is a fundamental quantity for the purpose of analysis and modelling premixed combustion, for example, in flame surface density based modelling approaches. According to Damköhler’s hypothesis it is closely related to the turbulent burning velocity, an equally important measure of the overall burning rate of a wrinkled flame. Three-dimensional evaluation of the area of highly wrinkled flames remains difficult and experiments are often based on planar measurements. As a result of this, model development and calibration require an extension of 2D measurements to 3D data. Different relations between 2D and 3D wrinkling factors are known in literature and will be discussed in the present work using a variety of direct numerical simulation (DNS) databases combined with theoretical arguments. It is shown, based on an earlier analysis, that the isotropic distribution of the surface area weighted probability density function of the angle between the normal vectors on the measurement plane and the flame surface, provides a very simple relationship, stating that the ratio between 3D and 2D flame surface area is given by <span>(4/pi )</span>, which is found to be in excellent agreement with DNS data of statistically planar turbulent premixed flames.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 2","pages":"519 - 526"},"PeriodicalIF":2.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10494-024-00622-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LES Prediction of the Ignition Probability Map for a Model Aeronautical Spray Burner","authors":"Ernesto Sandoval Garzon,&nbsp;Cédric Mehl,&nbsp;Olivier Colin","doi":"10.1007/s10494-024-00617-4","DOIUrl":"10.1007/s10494-024-00617-4","url":null,"abstract":"<div><p>This study presents the computation of the ignition probability map of a model gas turbine, investigated experimentally at CORIA laboratory, using Large Eddy Simulation (LES). The simulations leverage the recently proposed TFM-AMR-I model, which is based on the Thickened Flame Model (TFM) formalism and enables a full flame resolution (i.e. no thickening) of the flame kernel in the initial instants of ignition. LES simulations of ignition are performed for 14 spatial points distributed in the combustion chamber, with 6 repetitions for each in order to obtain a reasonable estimate of ignition probabilities. Probabilities are adequately predicted for most of the selected points, with a typical error of 30 <span>(%)</span>. Nevertheless, the ignition probability is largely over-estimated at two locations where the mean diameter of liquid droplets is shown to be under-predicted, which may lead to too easy ignitions. Parametric variations show a satisfying robustness of the proposed approach with the two following key highlights: (i) the initial full flame resolution made possible by TFM-AMR-I is necessary, as an abrupt initial thickening leads to an artificial extinction; (ii) a correction of the over-sensitivity of the thickened flame to stretch, recently proposed in the literature, is necessary to predict ignition accurately.</p></div>","PeriodicalId":559,"journal":{"name":"Flow, Turbulence and Combustion","volume":"114 2","pages":"449 - 467"},"PeriodicalIF":2.0,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}