Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines最新文献

{"title":"Use of an Integrated Approach for Analysis and Design of Turbocharged Internal Combustion Engine","authors":"T. Ebel, M. Anderson, Parth Pandya, M. Perchanok, Nick Tiney, Steve Gravante","doi":"10.1115/gt2021-60326","DOIUrl":"https://doi.org/10.1115/gt2021-60326","url":null,"abstract":"\u0000 When developing a turbocharged internal combustion engine, the choice of turbocharger is usually based on designer experience and existing hardware. However, proper turbocharger design relies on matching the compressor and turbine performance to the engine requirements so that parameters such as boost and back pressure, compressor pressure ratio, and turbine inlet temperatures meet the needs of the engine without exceeding its allowable operating envelope. Therefore, the ultimate measure of a successful turbocharger design is how well it is matched to an engine across various operating conditions. This, in turn, determines whether a new turbocharger is required, or an existing solution can be used.\u0000 When existing turbocharger solutions are not viable, the engine designer is at a loss on how to define a new turbocharger that meets the desired performance requirements. A common approach in industry has been to scale the performance of an existing turbocharger (compressor and turbine maps) and take these requirements for Original Equipment Manufacturers to possibly match it with a real machine. However, the assumptions made in a basic scaling process are quite simplistic and generally not satisfactory in this situation. A better approach would be to use a validated meanline model for a compressor and turbine instead, allowing to perform an actual preliminary design of such components. Such approach allows to link the engine performance requirements in a very early stage of te component design project and it guides the designer for the design decisions, such as rotor size, variable geometry nozzles, diameter, or shroud trims and others. Therefore, a feasible solution is more likely with design less iterations.\u0000 This paper describes a methodology for an integrated approach to design and analyze a turbocharged internal combustion engine using commercially available state-of-the-art 1D gas dynamics simulation tool linked to two powerful turbomachinery meanline programs. The outputs of this analysis are detailed performance data of the engine and turbocharger at different engine operating conditions.\u0000 Two case studies are then presented for a 10-liter diesel truck engine. The first study demonstrates how the programs are used to evaluate an existing engine and reverse engineer an existing turbocharger based only on the available performance maps. Then a second study is done using a similar approach but redesigning a new turbocharger (based on the reverse engineered one) for an increased torque output of the same engine.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134063212","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":"Prediction of Pressure Rise in a Gas Turbine Exhaust Duct Under Flameout Scenarios While Operating on Hydrogen and Natural Gas Blends","authors":"O. Ugarte, S. Menon, Wayne Rattigan, Paul Winstanley, Priyanka Saxena, M. Akiki, T. Tarver","doi":"10.1115/gt2021-59777","DOIUrl":"https://doi.org/10.1115/gt2021-59777","url":null,"abstract":"\u0000 In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125796802","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":"Influence of Supersonic Nozzle Design Parameters on the Unsteady Stator-Rotor Interaction in Radial-Inflow Turbines for Organic Rankine Cycles","authors":"A. Cappiello, R. Tuccillo","doi":"10.1115/gt2021-59123","DOIUrl":"https://doi.org/10.1115/gt2021-59123","url":null,"abstract":"\u0000 Organic Rankine Cycle (ORC) technology represents an interesting option for improving the efficiency of existing power plants and industrial processes as well as exploiting renewable and renewable-equivalent energy sources.\u0000 The use of Radial-Inflow Turbine (RIT) for ORC plant sizes below 100 kW is promising, although the application remains challenging. In fact, the single stage arrangement imposed by economic constraints and hence the large expansion ratio, together with the large molecular weight, which characterizes organic fluids, usually result in highly supersonic flows, so making the use of transonic stators often mandatory.\u0000 Particularly, the influence of RIT stator design parameters on losses and the level of unsteadiness seen by the subsequent rotor is still scarcely addressed in published literature.\u0000 Previous work by the authors investigated the effect of some stator design parameters on stator loss and downstream circumferential uniformity.\u0000 The present work investigates the effect of the convergent-divergent stators design parameters and the resulting downstream flow field non-uniformity on the unsteady stator-rotor interaction and loss generation in ORC Radial-Inflow Turbines.\u0000 To this end, two stator and rotor configurations which differ by the stator design parameters (i.e., discharge metal angle and number of vanes) have been tested by means of 3D unsteady CFD calculations accounting for real-gas properties.\u0000 The results show that larger stator-rotor interaction is present for the case featuring higher vane count and lower outlet metal, which also features the largest fluctuations of power output and pressure force on blade, together with a substantially lower average total-to-static efficiency.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127547148","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":"Gas Turbine Based Fuel Cell Vehicle Charging Station","authors":"M. Ganiger, M. Pandey, Rahul Wagh, Rakesh Govindasamy","doi":"10.1115/gt2021-60269","DOIUrl":"https://doi.org/10.1115/gt2021-60269","url":null,"abstract":"\u0000 Hydrogen as fuel for transportation sector is going to play a prominent role when it comes combating the climate change, as its only by-products are heat and water. Rapid surge in adoption rate for fuel cell vehicle (FCV) could be driven by improvements in fuel cell technology, as well as rise in number of Fuel Cell Vehicle Charging Station (FCVCS).\u0000 This paper explores how a gas turbine from the Baker Hughes™ portfolio can be used to create a circular economy model for hydrogen fueling stations. Solid Oxide Electrolyzer (SOE) and carbon capture unit are the two prime components that are integrated to the gas turbine. The SOE unit, powered by the gas turbine, generates hydrogen for refueling the FCVs and to use for itself as a blended fuel, bringing down the carbon footprint.\u0000 Proposed FCVCS solution can refuel about 250 FCVs in half a day of operation (50% power split). Economic analysis shows that the solution is lucrative with attractive return on investment. The solution is flexible to incorporate Power-to-X conversions. Modular nature of the solution makes it easy to implement in city limits as well as in remote locations, along the highways, where grid availability is a challenge.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131829070","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":"Matrix Crack Networks in SiC/SiC Composites: In-Situ Characterisation and Metrics","authors":"S. Jordan, S. Jeffs, C. Newton, L. Gale, P. Nicholson, M. Bache","doi":"10.1115/gt2021-03796","DOIUrl":"https://doi.org/10.1115/gt2021-03796","url":null,"abstract":"\u0000 Ceramic matrix composites can offer clear potential for a variety of engineering applications where the temperature capabilities of conventional metals are exceeded. Continued mechanical characterisation is essential to gain an understanding of their associated damage and failure mechanisms across a wide range of representative temperatures. The present paper will report ongoing research to characterize the initiation of matrix cracking at room temperature under tensile stress and subsequent damage development under fatigue loading in a SiCf/SiC composite. Imaging and mechanical property data were obtained via in-situ loading within a scanning electron microscope. The temporal nature of damage development was also recorded through the selective employment of acoustic emission. Metrics to describe the spatial distribution of cracks, crack lengths and crack opening displacement under load will be presented. The inspections also provided detailed evidence of the associated crack closure phenomena. The understanding of matrix crack saturation and matrix/fibre interfacial mechanics will be explored, together with the implications for the use of X-ray tomographic inspection of engineering components during service. The potential for these emergent techniques as a basis for future CMC characterization, via automated image recognition and machine learning, will be highlighted.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127913800","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":"Prediction of Dynamic Behavior of a Single Shaft Gas Turbine Using NARX Models","authors":"H. Asgari, E. Ory","doi":"10.1115/gt2021-58960","DOIUrl":"https://doi.org/10.1115/gt2021-58960","url":null,"abstract":"\u0000 Gas turbines are internal combustion engines widely used in industry as main source of power for aircrafts, turbo-generators, turbo-pumps and turbo-compressors. Modelling these engines can help to improve their design and manufacturing processes, as well as to facilitate their operability and maintenance. These eventually lead to manufacturing of gas turbines with lower costs and higher efficiency at the same time. The models may also be employed to unfold nonlinear dynamics of these systems.\u0000 The aim of this study is to predict the dynamic behavior of a single shaft gas turbine by using open-loop and closed-loop NARX models, which are subsets of artificial neural networks. To set up these models, datasets of significant variables of the gas turbine are used for training, test and validation processes. For this purpose, a comprehensive code is developed in MATLAB programming environment. In addition to the open-loop model, a closed-loop model is set up for multi-step prediction. The results of this study demonstrate the capability of the NARX models in reliable prediction of gas turbines’ dynamic behaviors over different operational ranges.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124701681","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":"A Marine Turbocharger Compressor Multi-Point 3D Design Optimization Tool","authors":"Konstantinos Ntonas, N. Aretakis, K. Mathioudakis","doi":"10.1115/gt2021-59518","DOIUrl":"https://doi.org/10.1115/gt2021-59518","url":null,"abstract":"\u0000 A marine turbocharger 3D compressor design tool, implemented on an existing marine turbocharger retrofit platform is presented. It produces 3D centrifugal compressor geometry for optimal compressor retrofit. It encompasses two modules, allowing the design process to become fully automatic.\u0000 First, a 1D compressor multi-point design optimization process is carried out, aiming to provide a fast and reliable solution based on Turbocharged diesel Engine range of operation. Structural integrity is ensured by using simplified structural analysis. Dimensionless parameters are used as optimization variables, for a given nominal compressor mass flow and power. Then a CFD compressor multi-point design optimization process is carried out, producing optimized 3D compressor geometry. It complies with the Turbocharged diesel Engine range of operation, while structural integrity is ensured by using Finite Element analysis.\u0000 A turbocharger compressor design case study is presented. First, a turbocharger 1D compressor design is carried out, aiming to at least reconstituting the original diesel engine performance. This first module provides a reliable compressor initial geometry for the 3D design module. A fully 3D compressor design is then performed, using a CFD-FEA optimization process, in order to provide an improved retrofitting solution.\u0000 Comparison between the multi-point and the traditional one-point design method, shows that the multi-point method provides a wider SFC reduction in the range that the Diesel engine normally operates.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133830594","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":"On the Challenge of Determining the Surge Limit of Turbocharger Compressors: Part 2 – Capabilities of a Geometrically Reduced Numerical Model","authors":"D. Paul, J. Ratz, W. Eißler","doi":"10.1115/gt2021-58840","DOIUrl":"https://doi.org/10.1115/gt2021-58840","url":null,"abstract":"\u0000 Steady-state numerical simulations are an essential instrument in the design process of centrifugal compressors for automotive turbochargers in an industrial environment. Although this method is state-of-the-art, the natural unsteadiness of the compressor flow especially close to stall and surge is suppressed by this kind of simulation.\u0000 Unsteady numerical simulations of the complete compressor geometry are necessary to detect unstable flow structures leading to surge. As numerical costs and thus the time needed for unsteady simulations correlate with the size of numerical setup, it is not possible for industrial applications to investigate an unsteady operation condition of a centrifugal compressor. On account of that fact, it would be beneficial to reduce the model and include only the most decisive components which are responsible for the significant flow phenomena within the impeller leading to surge.\u0000 The objective of this research paper is the investigation of the CFD simulation capabilities of a reduced radial compressor model for steady-state operation conditions using as a robust basis for further transient analysis. Thus, the results of a reduced model setup of one blade segment are compared to a full model setup.\u0000 It is concluded that the segment model approach is capable of investigating flow phenomena within the impeller without neglecting fundamental flow structures. In addition, the consequences of the geometric reduction to a diffuser segment without volute on different flow variables are studied. This provides the guidance for further transient studies.\u0000 The complete model setup, in conjunction with its validation by experimental data, serves as the starting point for this research paper. Dielenschneider et al.[1] present in the first part of the paper the procedure and a detailed comparison of complete model results with experimental analysis.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130033768","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":"Performance and Emission Assessment on a 3kW Micro Gas Turbine: Comparison of RANS and LES Predictions","authors":"Alessio Pappa, F. Nicolosi, A. Verhaeghe, L. Bricteux, M. Renzi, W. D. Paepe","doi":"10.1115/gt2021-59618","DOIUrl":"https://doi.org/10.1115/gt2021-59618","url":null,"abstract":"\u0000 Computational fluid dynamics represent a powerful tool to assess the performance of a combustor and identify possible issues/instabilities, helping thus e.g. to investigate the impact of advanced cycle modifications on the combustion in mGTs. The steady Reynolds-averaged Navier-Stokes (RANS) approach is still mostly used in this framework. With growing computational power, Large Eddy Simulation (LES) has gained more interest. LES provides higher details concerning flow structures and can better predict possible instabilities, specifically needed for advanced cycle modelling. On the other hand, LES remain rather challenging for real industrial applications. This work aims at providing an answer whether the advantages of LES justify the much higher computational costs. The objective of the present study is thus to assess the combustion performance and emissions of a typical small-scale 3.2 kWe micro gas turbine (mGT), using steady RANS and LES for various fuels. In this framework, a comparison of RANS and LES approaches (two levels of fidelity) is performed on a typical industrial case, to point out the strengths and weakness of each method with regard to industrial and research needs. The results show that both RANS (at a reduced cost) and LES can accurately predict the time-averaged trends of the main performance parameters, like temperature levels and emissions, also using various non-conventional inlet conditions. For the accurate prediction of the instabilities, the LES approach stands out as this approach takes into account the time-variation of the different quantities. Finally, a significant discrepancy has been observed between the CO levels provided by RANS and LES approaches where LES is overestimating the level of CO in the exhaust gases. Whereas it is difficult for LES to compete with convincing results provided by RANS, especially in the prediction of global emissions at reduced simulation cost, the LES strengths come out especially in flame and combustion stability analysis.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116271073","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 Analysis and Material Characterization of Ultra High Temperature Composites","authors":"A. Ghoshal, M. Walock, A. Nieto, M. Murugan, Clara Hofmeister-Mock, M. Pepi, L. Bravo, Andrew J. Wright, Jian Luo","doi":"10.1115/gt2021-60384","DOIUrl":"https://doi.org/10.1115/gt2021-60384","url":null,"abstract":"\u0000 Ultra high temperature ceramic (UHTC) materials have attracted attention for hypersonic applications. Currently there is significant interest in possible gas turbine engine applications of UHTC composites as well. However, many of these materials, such as hafnium carbide, zirconium carbide, and zirconium diboride, have significant oxidation resistance and toughness limitations. In addition, these materials are very difficult to manufacture because of their high melting points. In many cases, SiC powder is incorporated into UHTCs to aid in processing and to enhance fracture toughness. This can also improve the materials’ oxidation resistance at moderately high temperatures due to a crack-healing borosilicate phase. ZrB2-SiC composites show very good oxidation resistance up to 1700 °C, due to the formation of SiO2 and ZrO2 scales in numerous prior studies. While this may limit its application to hypersonic applications (due to reduced thermal conductivity and oxidation resistance at higher temperatures), these UHTC-SiC composites may find applications in turbomachinery, as either stand-alone parts or as a component in a multi-layer system.\u0000 The US Army Research Laboratory (ARL), the Naval Postgraduate School (NPS), and the University of California – San Diego (UCSD) are developing tough UHTC composites with high durability and oxidation resistance. For this paper, UHTC-SiC composites and high-entropy fluorite oxides were developed using planetary and high-energy ball milling and consolidated using spark plasma sintering. These materials were evaluated for their oxidation-resistance, ablation-resistance, and thermal cycling behavior under a DoD/OSD-funded Laboratory University Collaborative Initiative (LUCI) Fellowship and DoD Vannevar Bush Fellowship Program. In the present paper experimental results and post-test material characterization of SPS sintered ZrB2, ZrB2+SiC, ZrB2+SiC+HfC, HfC+SiC, and HfC+ZrB2 pellets subjected to ablation test are presented.","PeriodicalId":129194,"journal":{"name":"Volume 6: Ceramics and Ceramic Composites; Coal, Biomass, Hydrogen, and Alternative Fuels; Microturbines, Turbochargers, and Small Turbomachines","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116711636","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}