CFD Letters最新文献_第2页

Hybrid Nanofluid Flow over a Shrinking Darcy-Forchheimer Porous Medium with Shape Factor and Solar Radiation: A Stability Analysis 具有形状因子和太阳辐射的收缩达西-福克海默多孔介质上的混合纳米流体流动：稳定性分析

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.6081

Shahirah Abu Bakar, Nurul Syuhada Ismail, Norihan Md. Arifin

{"title":"Hybrid Nanofluid Flow over a Shrinking Darcy-Forchheimer Porous Medium with Shape Factor and Solar Radiation: A Stability Analysis","authors":"Shahirah Abu Bakar, Nurul Syuhada Ismail, Norihan Md. Arifin","doi":"10.37934/cfdl.16.11.6081","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.6081","url":null,"abstract":"This research aimed to develop a numerical solution to analyze the effects of solar radiation and nanoparticle shape factors on the flow of a hybrid nanofluid past a shrinking Darcy-Forchheimer porous medium. The base fluid chosen for this study is water (H2O), and the hybrid nanofluid consists of nanoparticles of silver (Ag) and titanium dioxide (TiO2) in four different shapes: bricks, cylinders, platelets, and blades. To account for solar radiation, the energy model incorporated a radiative heat flux, while the momentum problem considers the influence of a magnetic field. The application of an appropriate similarity transformation method converts the partial differential equations (PDEs) model into a system of nonlinear ordinary differential equations (ODEs). The mathematical model is solved using the shooting technique method and the bvp4c solver. The obtained results, along with the effects of the nanoparticle shape factor, solar radiation parameter, shrinking parameter, Darcy-Forchheimer number, and nanofluid volume fraction, are visually presented through figures and tables. It is worth noting that, in our numerical results, we observed the presence of dual solutions when λ < 0. Our findings indicate that the thermal transmittance increases with an increase in the nanoparticle shape factor and solar radiative parameter. Additionally, we observed an escalation in the velocity distribution in relation to the shrinking parameter and nanofluid volume fraction. Before reaching the two solutions, a flow stability analysis revealed that the first branch appears to be the most stable. Overall, these findings provide valuable insights into the behaviour of hybrid nanofluid flow in the presence of solar radiation and porous media.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"111 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141674212","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}

引用次数: 0

Investigating the Actuation of Sidewall Sprinkler in an Atrium Using CFD Simulation 利用 CFD 仿真研究中庭侧墙喷淋器的启动问题

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.92110

Jaime III Reyes, Jaime Honra

引用次数: 0

The Effect of Perforated Plate Geometry on Thermofluid Characteristics of Briquette Drying Oven: A 3D Computational Fluid Dynamics (CFD) Study 穿孔板几何形状对煤坯烘干炉热流体特性的影响：三维计算流体动力学 (CFD) 研究

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.111132

Samsudin Anis, Krisna Tri Romadhoni, Deni Fajar Fitriyana, Aldias Bahatmaka, Hendrix Noviyanto Firmansyah, Natalino Fonseca Da Silva Guterres

{"title":"The Effect of Perforated Plate Geometry on Thermofluid Characteristics of Briquette Drying Oven: A 3D Computational Fluid Dynamics (CFD) Study","authors":"Samsudin Anis, Krisna Tri Romadhoni, Deni Fajar Fitriyana, Aldias Bahatmaka, Hendrix Noviyanto Firmansyah, Natalino Fonseca Da Silva Guterres","doi":"10.37934/cfdl.16.11.111132","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.111132","url":null,"abstract":"The process of drying briquettes in an oven is very costly due to the amount of fuel, labor, and drying time required. Furthermore, inadequate air circulation also results in an uneven and ineffective drying process for briquettes. The performance of the briquette drying oven can be improved by changing the geometry of the perforated plate in the oven to optimize the air distribution. This research process was conducted through Computational Fluid Dynamics (CFD) simulations using Ansys Fluid Flow (Fluent) software by testing three different perforated plate geometries in the oven to determine their effect on the air distribution that occurred in the oven. The research findings indicate that the temperature, velocity, pressure, and airflow pattern of the air are all considerably impacted by the incorporation of perforated plates into the first, second, and third geometries of the oven. When compared to the original geometry, the average air temperature in ovens using the first, second, and third geometries increased by 6.86%, 7.38%, and 9.15%, respectively. Average air velocity increased by 226.04%, 235.77%, and 431.60% in ovens with the first, second, and third geometries. However, the air pressure in ovens with the first, second, and third geometries decreased by 11.05%, 8.62%, and 10.66%. The use of perforated plates on the right, back, and left sides in an oven with the third geometry is the best geometry produced in this research. This happens because this oven produces the most even airflow pattern in the oven compared to other geometries. In addition, the oven with the third geometry has the highest average temperature and average air velocity, with a lower average air pressure compared to the other geometries. Consequently, drying is more effective and takes less time.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 32","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141673552","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}

引用次数: 0

Effect of Chamfered Turbulators on Performance of Solar Air Heater - Numerical Study 倒角涡轮对太阳能空气加热器性能的影响 - 数值研究

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.1736

Arunkumar H S, Madhwesh N, Anirudh Hegde K, Manjunath Mallashetty Shivamallaiah, Kota Vasudeva Karanth, Younes Amini

{"title":"Effect of Chamfered Turbulators on Performance of Solar Air Heater - Numerical Study","authors":"Arunkumar H S, Madhwesh N, Anirudh Hegde K, Manjunath Mallashetty Shivamallaiah, Kota Vasudeva Karanth, Younes Amini","doi":"10.37934/cfdl.16.11.1736","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.1736","url":null,"abstract":"This paper presents a numerical analysis of the thermal performance improvement in a flat plate solar air heater equipped with chamfered turbulators attached below the absorber plate for evaluating performance for Reynolds numbers ranging from 3,000 to 21,000. According to the research, chamfered turbulators caused the flow to become highly turbulent. This flow behaviour with flow separation around the turbulators positively affects performance. This paper attempts to explain the complex flow behaviour found during the analysis. The turbulator diameter varies in 1 mm increments from 3 to 7 mm at a constant longitudinal pitch of 200 mm. The number of turbulator rows in the transverse direction is kept constant at three. The chamfer is represented by the flow attack angle, which can be 30°, 45°, or 60° facing the direction of flow and opposing the direction of flow. The results showed that a 7mm diameter turbulator with a 30° chamfer angle placed against the flow of air yielded a considerably more significant thermal enhancement factor of 1.15 over the spectrum of flow Reynolds number studied","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141674491","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}

引用次数: 0

CFD Analysis of Counter-Rotating Vane-Type Wing Vortex Generator for Regional Aircraft 支线飞机反旋转叶片式机翼涡流发生器的 CFD 分析

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.116

Gunawan Wijiatmoko, Eflita Yohana, Putro Adi Nugroho, Mohammad Tauviqirrahman, Ivransa Zuhdi Pane

{"title":"CFD Analysis of Counter-Rotating Vane-Type Wing Vortex Generator for Regional Aircraft","authors":"Gunawan Wijiatmoko, Eflita Yohana, Putro Adi Nugroho, Mohammad Tauviqirrahman, Ivransa Zuhdi Pane","doi":"10.37934/cfdl.16.11.116","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.116","url":null,"abstract":"Vortex generator is a component that has a significant impact on aircraft performance. The function of the vortex generator is to create vortices that can optimize the aerodynamic performance of aircraft wings by avoiding air flow separation and increasing lift at high angle of attack. Vortex generator can provide increased lift during take-off and landing due to the increased wing angle of attack. Although the use of vortex generator can be carried out using an experimental approach, a computational fluid dynamic approach to determine the influence of geometric parameters and placement of the vortex generator needs to be carried out. The aim of this research is to determine the effect of parameters like placement on the wing chord, height of the boundary layer, length, shape, angle of incidence and distance between pairs on the lift and drag. The model used as a computational fluid dynamic calculation model is the Spalart Allmaras transient model. As a result, vortex generator does not always have a good effect on aerodynamics. All configurations have a negative influence on the lift and drag values, but the flow separation phenomenon can be reduced significantly. Of all the configurations, the best configuration is obtained by exhibiting an ogive shape, positioned at 13.8% of the chord length, set at a 13o angle of incidence. The vortex generator should have a height closely matching the boundary layer, with a length 6.5 times the height and a pair spacing of 6.7 times the height","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141674574","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}

引用次数: 0

The Properties of the Physical Parameters in the Triple Diffusive Fluid Flow Model 三重扩散流体流动模型中的物理参数特性

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.133145

Siti Suzilliana Putri Mohamed Isa, Nanthini Balakrishnan, Kartini Ahmad, Norihan Md. Arifin, Fadzilah Md Ali

{"title":"The Properties of the Physical Parameters in the Triple Diffusive Fluid Flow Model","authors":"Siti Suzilliana Putri Mohamed Isa, Nanthini Balakrishnan, Kartini Ahmad, Norihan Md. Arifin, Fadzilah Md Ali","doi":"10.37934/cfdl.16.11.133145","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.133145","url":null,"abstract":"The existence of more than one diffusive component in fluid mixtures is observed in these situations: underground water flow, the mechanism of acid rain, the existence of contaminant in some certain mixture, etc. These diffusive components are occurred with the single temperature gradient (since all of the elements are dissolved into the same mixture) and 2 types of concentration gradients (since the dual diffusive components are dissolved in the same mixture). Besides, many industrial and engineering processes are utilizing the concept of convective fluid flow especially over a shrinking sheet. Therefore, a mathematical model for triple-diffusive flow over a nonlinear compressing sheet has been developed in this paper, and subjected to the Soret-Dufour effects. The model comprises of five initial equations namely continuity, momentum, energy, concentration of component 1 and concentration of component 2 equations, together with boundary conditions. These initial equations are expressed as partial differential equations. However, the finalized equations are in the form of ordinary differential equations. Later, the bvp4c programme provided by the Matlab Software is used to solve the ordinary differential equations and the boundary conditions. Three distinct values of each governing parameter are fixed into the bvp4c function, to observe the behaviour of the physical parameters, namely as local Nusselt number and local Sherwood number. The main finding of the dual numerical solutions varies for increasing governing parameters until they intersect at the critical points. In conclusion, the governing parameters affects the heat and mass transfer of the fluid flow model model.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141676026","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}

引用次数: 0

Computational Elucidation of Electromagnetic Effects on Peristaltic Nanofluid Transport in Microfluidics: Intersections of CFD, Biomedical and Nanotechnology Research 计算阐明电磁对微流控蠕动纳米流体传输的影响：CFD、生物医学和纳米技术研究的交叉点

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.3759

Hanumesh Vaidya, Rajashekhar Choudhari, Fateh Mebarek-Oudina, Kerehalli Vinayaka Prasad, Manjunatha Gudekote, Balachandra Hadimani, Sangeeta Kalal, Shivaleela

{"title":"Computational Elucidation of Electromagnetic Effects on Peristaltic Nanofluid Transport in Microfluidics: Intersections of CFD, Biomedical and Nanotechnology Research","authors":"Hanumesh Vaidya, Rajashekhar Choudhari, Fateh Mebarek-Oudina, Kerehalli Vinayaka Prasad, Manjunatha Gudekote, Balachandra Hadimani, Sangeeta Kalal, Shivaleela","doi":"10.37934/cfdl.16.11.3759","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.3759","url":null,"abstract":"This computational study elucidates electromagnetic field effects on peristaltic transport of nanofluids in microfluidic channels using CFD modeling. The feasibility of electroosmotic micropumping for biomedical applications has garnered interest. However, the unique properties and motion of nanofluids warrant investigation. This work examines the impact on peristaltic heat and mass transfer in a non-uniform microchannel geometry incorporating electroosmosis. By explicitly accounting for electroosmotic factors, the coupled PDE system is solved to obtain concentration, temperature and velocity fields. While the electromagnetic simulations prove essential, a key focus lies on electroosmosis phenomena. Effects on parameters including skin friction, Nusselt and Sherwood numbers are analyzed for Casson and Newtonian nanofluids. Visual probing of trapping events further reveals the role of electroosmosis. Overall, this computational approach provides insights into the multifaceted interplay between peristalsis, nanofluids and electroosmotic flows under electromagnetic forces in microfluidic configurations. The perspectives gained at intersection of CFD, biomedical and nanotechnology domains can facilitate optimized designs of electroosmosis-driven biomedical microdevices.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 35","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141675557","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}

引用次数: 0

Numerical Optimization for Aerodynamic Performance of Nose Cone of FSAE Vehicle through CFD 通过 CFD 数值优化 FSAE 赛车鼻锥的空气动力性能

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.15.11.161171

Amol Dhumal, Nitin Ambhore, Pradip Tamkhade, Atharv Marne, Nihal Muzawar

{"title":"Numerical Optimization for Aerodynamic Performance of Nose Cone of FSAE Vehicle through CFD","authors":"Amol Dhumal, Nitin Ambhore, Pradip Tamkhade, Atharv Marne, Nihal Muzawar","doi":"10.37934/cfdl.15.11.161171","DOIUrl":"https://doi.org/10.37934/cfdl.15.11.161171","url":null,"abstract":"This paper presents the optimization and aerodynamic performance of a Formula SAE vehicle nose cone. The purpose of the study is to minimize drag while simultaneously enhancing downforce to improve traction and acceleration of the vehicle. Numerous CAD models of the nose cone were developed, taking into account factors such as chassis dimensions, ground clearance, and Formula SAE rulebook constraints. Computational Fluid Dynamics (CFD) analysis is carried out in ANSYS 2021 Fluent module. The fluid domain was created and meshed using tetrahedral cells, and the flow field was predicted using the Realizable k-ε turbulence model. The simulation results revealed essential information including drag and lift coefficients, as well as pressure and velocity contours. An in-depth analysis of lift and drag coefficients guided the optimization of the nose cone design. The study ultimately identified a nose cone design that yielded the most favorable drag coefficient and is found in the range between 0.2-0.3. The study also observed that the down force is increased by 27%. This design proved highly effective in reducing the vehicle's drag and sufficient downforce to enhance acceleration.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141676255","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}

引用次数: 0

The Rheological and Energy Study of the Blade Torsion Effect in a Vessel Stirred by Two- Blade Impeller 双叶叶轮搅拌容器中叶片扭转效应的流变学和能量研究

CFD Letters Pub Date : 2024-07-05 DOI: 10.37934/cfdl.16.11.8291

youcef Kamla, Houari Ameur, Mousaab Beloudane, zied Driss, Abdessalam Hadjeb

{"title":"The Rheological and Energy Study of the Blade Torsion Effect in a Vessel Stirred by Two- Blade Impeller","authors":"youcef Kamla, Houari Ameur, Mousaab Beloudane, zied Driss, Abdessalam Hadjeb","doi":"10.37934/cfdl.16.11.8291","DOIUrl":"https://doi.org/10.37934/cfdl.16.11.8291","url":null,"abstract":"This work presents a comprehensive numerical study on the hydrodynamic behaviour and power consumption of a cylindrical vessel stirred by a two-blade impeller, employing the simulation by the RRF method (Rotation Reference Frame). The study focuses on addressing the issue of power consumption in the context of blade orientation referring to different values equal to α=15°, α=30°, α=45°, α=90°, α=135°, and α=180°. The primary objective is to identify a novel design that promotes effective fluid circulation and exhibits lower energy consumption compared to standard geometries. By employing the commercial CFD code ANSYS CFX 14.0, the research delves into the impact of fluid rheology and blade curvature on mixing efficiency. The validation of the results, achieved by comparing them with data from existing literature, demonstrated a satisfactory agreement. According to our obtained results, it has been observed that the energy consumption decreases when the blade orientation exceeds 90°. This study contributes valuable insights into both blade orientation and Reynolds number effects (ranging from 1 to 100 for laminar flow), with the ultimate goal of proposing innovative designs that optimize fluid mixing efficiency while minimizing the consumed energy.","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":" 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141673812","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}

引用次数: 0

Numerical Model Parameters Choice of Helical Savonius Wind Rotor: CFD Investigation and Experimental Validation 螺旋萨沃尼乌斯风力转子的数值模型参数选择：CFD 研究与实验验证

CFD Letters Pub Date : 2024-06-02 DOI: 10.37934/cfdl.16.10.94111

mariem lajnef, Mabrouk Mosbahi, abid Hasna, zied Driss, Emanuele Amato, Tullio Tucciarelli, Marco Sinagra

{"title":"Numerical Model Parameters Choice of Helical Savonius Wind Rotor: CFD Investigation and Experimental Validation","authors":"mariem lajnef, Mabrouk Mosbahi, abid Hasna, zied Driss, Emanuele Amato, Tullio Tucciarelli, Marco Sinagra","doi":"10.37934/cfdl.16.10.94111","DOIUrl":"https://doi.org/10.37934/cfdl.16.10.94111","url":null,"abstract":"Electrical power is essential for human beings welfare. The available wind as a clean and renewable source of energy has whetted extensive interest over decades. Savonius vertical axis wind rotor as an energy converter has the merit of being adequate for specific implementations owing to its lower cost and independency on wind direction. From this perspective, multiple studies have been conducted to boost its efficiency. This research work emphasizes on the helical Savonius wind rotor (HSWR). The basic objective is to investigate the impact of selecting the numerical model parameters on its aerodynamic and performance characteristics. Experimental tests were realized with a 3D printed HSWR in a wind tunnel. The experimental performances in terms of power, static and dynamic torque coefficients were addressed. Next, a numerical study was undertaken through Ansys Fluent 17.0 software. Grid, turbulence model and rotating domain size tests were examined. Good accordance was obtained, which validated the numerical model with an averaged error of 5%. The maximum power coefficient proved to be equal to 0.124 at a tip speed ratio of 0.73 and 0.1224 at a tip speed ratio of 0.69, respectively, numerically and experimentally","PeriodicalId":9736,"journal":{"name":"CFD Letters","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273966","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}

引用次数: 0