Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling最新文献

{"title":"Investigation of Unsteady Flow Characteristics in Axial Rim Seal","authors":"X. Lei, Du Qiang, L. Guang, Lian Zengyan, Ran Ren","doi":"10.1115/gt2021-58822","DOIUrl":"https://doi.org/10.1115/gt2021-58822","url":null,"abstract":"\u0000 Unsteady flow structures have been observed and reported in a number of recent rim-sealing investigations. These unsteady flow structures will influence the cavity pressure distribution, therefore influence the sealing efficiency. As a result, it is important to determine the mechanisms of these unsteady flow structures and how they influence the hot gas ingestion and sealing efficiency. A two-sector axial rim seal model is used to carry out the numerical investigation. The simulation is performed using the URANS method by the commercial CFD code ANSYS CFX, in which the SST turbulent model is applied. The mechanism and influence of the unsteady flow structures are analyzed. It was found that two different types of unsteadiness are observed inside the wheel space cavity: radial large flow structures dominated by the mainstream pressure distribution and inertia wave, and circumferential Kelvin-Helmholtz vortexes induced by circumferential velocity discontinuous distribution. The number and rotating speed of the radial and circumferential flow structures can be calculated using a cross-correlation method, and it was found that they can lead to a deeper ingress. By increasing the sealing flow rate, the pressure fluctuation inside the wheel space cavity is suppressed and the rotating speed of the flow structures is deaccelerated; thus, the sealing flow stabilizes the flow inside the wheel space cavity. Meanwhile, the K-H vortices’ position is lifted by the increased sealing flow rate, and the strength of the K-H vortices is suppressed, thus the sealing efficiency inside the wheel space cavity is also improved.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","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":"128330451","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":"Multi-Objective Optimization on the Fluid Flow and Heat Transfer of Semi-Attached Rib-Channels","authors":"Xu Wang, Huazhao Xu, Jian-hua Wang, Yuefeng Li, W. Song","doi":"10.1115/gt2021-58725","DOIUrl":"https://doi.org/10.1115/gt2021-58725","url":null,"abstract":"\u0000 Rib-turbulators have been widely used in turbine blade cooling designs to enhance internal heat transfer. However, application of the ribs in blade cooling channels inevitably causes large pressure losses and lower heat transfer areas behind the ribs and at the joint parts of the ribbed wall with sidewalls in comparison to smooth channels. Semi-attached rib having two rectangular holes at the bottom of the ribs at the joint regions of the ribbed wall and two sidewalls is able to reduce friction losses and alleviates lower heat transfer in the channels. This paper presented a method of combining computational fluid dynamic simulation with an optimization method to optimize the performance of a channel with semi-attached ribs and to discuss the effects of hole geometric variables on both pressure losses and heat transfer enhancement. A fully automatic multi-objective genetic algorithm based on the Non-dominated Sorted Genetic Algorithm-II is applied for a one-pass squared channel with 60° inclined semi-attached ribs. Four geometrical variables are widths and heights of the two rectangular holes, and two objective functions are the maximum of area-averaged Nusselt number on the rib roughend wall and the minimum of friction factor. The Kriging model is constructed by using the Latin hypercube sampling method to choose 15 experimental points in the design space. The results showed that the optimization method helps to increase the channel performance and to eliminate nearly all low heat transfer areas by appropriately adjusting the heights and widths of the holes. Compared to solid ribs, the optimal semi-attached rib increases the area-averaged Nu number on the rib-roughened walls by 9.45%, whereas the friction factor in the channel is decreased by 6.95%, which corresponds to an increase of 12.13% in thermal performance. In the optimal model, the existence of large holes on the right side of the optimal semi-attached ribs moves the vortex core of the secondary flow downstream of the ribs from the right side of the solid-ribbed channel to the middle, which causes a large increase in Nu number on the middle and left side of the rib roughened walls and only a moderate reduction in Nu number on the right part of the walls. In the whole range discussed, heat transfer coefficient on the rib-roughened walls increased with the height of the right holes, but it increases with the width of the hole only in the range of 8–10mm. For the holes on the left, heat transfer coefficient deteriorates as the height and width increase. Increasing width and height of the holes on both sides of the semi-attached ribs reduces the channel friction losses.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"112 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":"131416649","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":"Effect of Jet-to-Jet Distance and Pipe Position on Flow and Heat Transfer Features of Active Clearance Control Systems","authors":"Lorenzo Cocchi, A. Picchi, B. Facchini, R. D. Soghe, L. Mazzei, L. Tarchi, L. Descamps, Maxime Rotenberg","doi":"10.1115/gt2021-59158","DOIUrl":"https://doi.org/10.1115/gt2021-59158","url":null,"abstract":"\u0000 The goal of the present work is to investigate the effect of supply pipe position on the heat transfer features of various active clearance control (ACC) geometries, characterized by different jet-to-jet distances. All geometries present 0.8 mm circular impingement holes arranged in a single row. The jets generated by such holes cool a flat target surface, which is replicated by a metal plate in the experimental setup. Measurements are performed using the steady-state technique, obtained by heating up the target plate thanks to an electrically heated Inconel foil applied on the side of the target opposite to the jets. Temperature is also measured on this side by means of an IR camera. Heat transfer is then evaluated thanks to a custom designed finite difference procedure, capable of solving the inverse conduction problem on the target plate.\u0000 The effect of pipe positioning is studied in terms of pipe-to-target distance (from 3 to 11 jet diameters) and pipe orientation (i.e. rotation around its axis, from 0° to 40° with respect to target normal direction), while the investigated jet Reynolds numbers range from 6000 to 10000. The obtained results reveal that heat transfer is maximized for a given pipe-to-target distance, dependent on both jet-to-jet distance and target surface extension. Pipe rotation also affects the cooling features in a non-monotonic way, suggesting the existence of different flow regimes related to jet inclination.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"332 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":"122641573","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":"Local Heat Transfer and Friction Measurements in Ribbed Channel at High Reynolds Numbers","authors":"Igor N. Baybuzenko","doi":"10.1115/gt2021-00259","DOIUrl":"https://doi.org/10.1115/gt2021-00259","url":null,"abstract":"\u0000 The power generation industry is targeting heavy duty gas turbine to increase power and efficiency. Hot gas temperature and massflow are continuously being increased. It brings new challenges for the design of cooling systems for turbine blades and vanes. Up to date most of studies of heat transfer in internal cooling channels were in the range of Reynolds numbers below 80,000 for cooling air flow, for example, experimental series done by J. Chin Han et al. since 1985. Actually the range of Reynolds numbers is increased with the increase of total massflow. Extrapolation of available data is not reliable while local distribution of heat transfer coefficients becomes critical in terms of thermal stresses. Only few recent studies deal with the range of Reynolds number above 80,000, for example, in 2009 J. Chin et. al showed results for 45° angled ribs provided only area averaged values for heat transfer coefficient over one pitch and in 2003 R. Bunker showed local distribution for 45° angled ribs only. Within current study the experimental measurements of local heat transfer and friction in ribbed cooling channel were performed for Reynolds numbers in range of 100,000 – 180,000, what fits the parameters of modern and perspective heavy duty gas turbines. Using thermochromic liquid crystal technology the following rib configurations were tested: angled 45°, 60°, 90° and chevron 45°, 60°; pitch to height ratio of 10; rib turbulator height-to-channel hydraulic diameter ratio of 0.083. Maximum averaged heat transfer value was provided by 60° angled ribs. Comparison of local distribution of heat transfer coefficients for considered configurations was performed. Minimum non-uniformness of heat transfer coefficient was provided by chevron ribs, having maximum friction factor. Conjugated thermal-hydraulic analysis for cooled vane for heavy duty gas turbine was performed in order to quantify the effect of local heat transfer coefficient distribution in ribbed cooling channel. Metal temperature calculation was performed for two cases of air side thermal boundary condition application for wall surface between rib-turbulators: averaged value of heat transfer coefficient and detailed local distribution. Comparison of calculated metal temperature for 2 cases shows that usage of locally distributed air side heat transfer coefficient is important and should increase the accuracy of temperature prediction by 50°C. Consideration of local distribution of heat transfer coefficient is important for cooling design of modern heavy duty gas turbine in order to provide acceptable thermal gradients and consequently reach lifetime targets.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"183 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":"121947376","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 a New Rotating Turbine Research Facility For Investigating the Interaction Between Mainstream and Various Secondary Air at Relevant Engine Conditions","authors":"Y. Okita, H. Futamura, Takashi Yamane, Masaya Suzuki, N. Tanaka, Haruyuki Tanimitsu, Junichi Iguchi","doi":"10.1115/gt2021-58806","DOIUrl":"https://doi.org/10.1115/gt2021-58806","url":null,"abstract":"\u0000 This paper reports a new turbine research facility that was recently completed in Japan Aerospace Exploration Agency (JAXA). The facility is a full annular rotating transonic turbine rig that allows a continuous operation of scaled and/or full-scale axial HPT or LPT.\u0000 The rig design was especially focused on the ability of simulating the aerodynamic and thermal interaction between main gas paths and various / massive secondary air flows at conditions of dominant aero-heat parameters well matched to those of modern aero-engines. Cooling air can be delivered to the airfoils of vanes/blades and the endwalls separately at a massflow range covering the typical conditions. Rotor forward and aft purge air as well as through-casing cooling air can be injected with each flowrate independently controlled.\u0000 The facility, which has significant capabilities with several large compressors of 10MW in total, 5MW mainflow heater, 6MW drive motor/generator, etc., can be applied to a very wide range of turbine designs.\u0000 A series of shakedown testing has been carried out since the completion of construction in 2019. The commissioning phase of the rig will complete in early 2021 and then the rig will enter service. The very first test with a scaled HPT is planned to start in the last quarter of 2021.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"9 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":"127960622","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":"Effect of Pin Fins on Jet Impingement Heat Transfer on A Rotating Disk","authors":"Pratik S. Bhansali, K. Ramakrishnan, S. Ekkad","doi":"10.1115/gt2021-59797","DOIUrl":"https://doi.org/10.1115/gt2021-59797","url":null,"abstract":"\u0000 Heat transfer on rotating surfaces is a predominant phenomenon in rotating machinery as in the case of the gas turbine disk. The gas turbine disk needs to be cooled as well as protected from the ingress of hot turbine gases in the stator-rotor cavity. In the current study, an experimental investigation of the heat transfer of an impinging air jet on a surface rotating at low rotational Reynolds number has been carried out. Addition of pin-fins on the disk surface is an effective way to enhance the heat transfer between the disk and the jet of cooling air. The effect of addition of an inline array of square pin fins on the rotating disk heat transfer has been investigated in this study. Steady state measurements have been carried out using thermocouples embedded at different locations in an aluminum disk with an array of square pin-fins rotating in a large space. Experiments have been conducted at rotational Reynolds numbers (ReR) of 5,487–12,803 based on the disk diameter (D) and jet Reynolds numbers (Re) of 5,000–18,000 based on the jet diameter (d). Two different ratios of jet to nozzle spacing and jet diameter (z/d) of 2 and 4 and three different impingement locations – at eccentricities (ε) – 0, 0.33 and 0.67 have been considered. The diameter of the impinging jet has been kept constant in order to maintain an equal jet footprint across all the cases. The area averaged Nusselt number over the surface with pin fins has been compared with a smooth rotating disk of equal diameter. Results indicate that for the smooth surface, ε and ReR have negligible effect on Nu. However, addition of pin fins enhance Nu by a factor between 1.5 and 3.9 in the present study. Qualitative visualization of flow field has been performed using the commercial simulation package Ansys Fluent to further understand the heat transfer trends.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"56 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":"125148192","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":"Modelling Conjugate Heat Transfer Within a Gas Turbine Secondary Air System Using 1D and 2-3D Solid Models in Thermo-Fluid System Simulation","authors":"D. Hunt, Youming Yuan, Ian Gardner","doi":"10.1115/gt2021-59930","DOIUrl":"https://doi.org/10.1115/gt2021-59930","url":null,"abstract":"\u0000 This paper presents an implicit conjugate heat transfer (CHT) model designed for 1D systems of both solids and fluids. It demonstrates that this approach can be extended to include 2D and 3D elements being co-solved in a 2D or 3D thermal product. The approach is applied to a simple analytical problem and then to a Secondary Air Cavity within a Gas Turbine to illustrate the potential of this technique to be applied to more complex thermo-fluid simulations. Such simulations are important in trade off studies to balance minimizing engine bleed whilst ensuring sufficient cooling. The benefits of this CHT model are presented by comparison with the traditional approach of explicit co-simulation in which the temperature from the fluid domain is applied as a boundary condition to the thermal simulation and heat flux from the thermal simulation is applied as a boundary condition to the fluid domain (or vice versa). The ability to replace 1D elements with 2D or 3D elements allows model continuity from conceptual to detailed design and the reverse process potentially offers a route for model reduction later in lifecycle to support operation and maintenance through the use of an executable digital twin.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"61 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":"130442273","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":"Physics-Based Thermal Management System Components Design for All-Electric Propulsion Systems","authors":"S. Jafari, T. Nikolaidis, Roopesh Chowdary Sureddi","doi":"10.1115/gt2021-59995","DOIUrl":"https://doi.org/10.1115/gt2021-59995","url":null,"abstract":"\u0000 Although electrification allows a significant reduction in fuel burn, noise, and emissions, one of the main challenges in this technology is to deal with the thermal loads generated by the electrified propulsion system components. This is to guarantee the safe and optimal operation of the propulsion system as well as the aircraft. This challenge needs to be addressed to enable this important technology to be adopted by aircraft manufacturers. This paper presents a methodological approach to calculate the heat load values generated by electric components in All-Electric Propulsion (AEP) architectures. Initially, the architecture of an AEP system will be presented and explained. Then, for each component, physics-based models based on associated heat loss mechanisms will be developed and presented. For this purpose, thermal models for battery packs, electric motors, inverters, and rectifiers are generated and a MATLAB/Simulink library is developed to calculate the thermal loads generated by each component at different working conditions. The developed models’ results are validated against publicly available data to confirm the effectiveness of the proposed approach. The simulation results confirm that the developed library is able to predict the thermal loads generated by lithium-ion battery packs, permanent magnet synchronous electric motors, multi-stage inverters, and rectifiers with less than 1%, 9.9%, 9.2%, and 0.5% errors respectively. Finally, an AEP architecture is simulated as the case study and the total heat loads generated by different components have been calculated at the design point to confirm the capability of the developed framework in system-level analyses.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"11 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":"127790458","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":"Numerical Investigation of Array Impingement Heat Transfer on the Target With Advanced Pin Fins","authors":"T. Guo, Yun-Peng Ben, Y. Liu, Cun-liang Liu, Hui-ren Zhu","doi":"10.1115/gt2021-58813","DOIUrl":"https://doi.org/10.1115/gt2021-58813","url":null,"abstract":"\u0000 The paper proposes a technique of using advanced pin fins on a target plate to improve the impingement heat transfer performance in an array impingement cooling system. The initial shape of the advanced pin fin is a frustum of a cone. In order to enhance heat transfer and reduce flow resistance, the upper and lower sharp edges of the frustum of a cone are rounded. There are arrays of film holes on the target plate, and the influence of the crossflow is not considered. The flow and heat transfer characteristics of the array impingement flat plate and advanced pin fin plate were studied by numerical simulation. During the numerical simulation, the Reynolds number was varied from 2000 to 19500, the jet-to-plate spacing Z/d from 3 to 6 (d = 0.50mm) and the jet hole diameter d is 0.50 mm, 0.75 mm and 1.00 mm respectively. The results show that the averaged Nusselt number values for the advanced pin fin target plate showed an increase ranging from 15% to 20% over those for the flat target plate, It is generally considered that the enhancement of heat transfer is mainly due to the enhancement of fluid disturbance by the pin fins. However, by changing the size of the pin fins, it is found that the enhancement of heat transfer is mainly caused by the increase of heat transfer area, and the influence of enhancing the disturbance is not significant. The pressure loss is little higher than that of the flat plate.\u0000 The averaged Nusselt number values for the advanced pin fin target plate decreases with the increase of the jet-to-plate spacing, and increases with the increase of Reynolds number. At the same mass flow rate, the averaged heat transfer performance of the pin fin target plate decreases with the increase of jet hole diameter, and the results show that the averaged heat transfer performance of 0.5mm jet hole diameter is the best.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"113 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":"123556855","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":"Heat Transfer Enhancement in a Double Sequential Impingement Channel","authors":"M. Gaffuri, P. Ott, S. Naik, M. Henze","doi":"10.1115/gt2021-58913","DOIUrl":"https://doi.org/10.1115/gt2021-58913","url":null,"abstract":"\u0000 Sequential impingement channels can reduce the adverse effect of crossflow in narrow impingement channels, as well as increase the cooling efficiency. In this work, sequential impingement channels are experimentally investigated using the transient liquid crystal technique to assess their thermal performances. A low heat transfer region is identified in the downstream part of the first channel where the flow is discharged into the second plenum. Various means of increasing the heat transfer at this location are investigated. Ribs on the target plate allow for an increase of the average heat transfer coefficient with small losses in pressure. Reducing the channel cross-section increases the mean flow velocity and, combined with the ribs, allows for a further increase of the heat transfer. Additionally, the geometrical changes of the channel caused by the addition of a ramp with a rounded corner, allow to decrease the pressure losses associated with the discharge into the second plenum, which is not optimal in the baseline configuration due to the sharp corner of the purge hole. Further reducing the cross-section to increase the heat transfer, however, increases the pressure losses due to the small open area in the transition zone.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"31 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":"129422199","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}