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学者姓名:席光
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Abstract :
本文试图通过神经网络重构二维低雷诺数翼型绕流非定常流场.首先通过局部径向基函数(LRBF)求解器求解不可压缩流动控制方程得到计算域内流场信息,然后随机选取一些时空域内的数据点(包含位置信息和速度信息)作为训练数据代入神经网络进行训练.先学习训练得到流动的雷诺数后进行流场的重构,并与LRBF求解器得到的数值结果进行对比.流动计算中雷诺数设置为200,攻角为20°,计算域离散采用局部节点加密技术以减少计算量.
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GB/T 7714 | 王同生 , 孙中国 , 黄柱 et al. 神经网络对于翼型绕流流场的重构 [J]. | 工程热物理学报 , 2021 , 42 (5) : 1205-1212 . |
MLA | 王同生 et al. "神经网络对于翼型绕流流场的重构" . | 工程热物理学报 42 . 5 (2021) : 1205-1212 . |
APA | 王同生 , 孙中国 , 黄柱 , 席光 . 神经网络对于翼型绕流流场的重构 . | 工程热物理学报 , 2021 , 42 (5) , 1205-1212 . |
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Present paper attempts to reconstruct 2D unsteady flow field using neural network when fluid flows past airfoils at low Reynolds number. First of all, the details of fluid domain are obtained by solving incompressible fluid governing equation using our own developed fluid solver based on local radial basis function (LRBF) method, and then some randomly selected tempo-spatial points (with velocities and pressure information) are fed into neural network to train. The training process of first step is to learn Reynolds number, continuing with reconstruction of fluid field and comparison with numerical results. The flow Reynolds number is set as 200, while angle of attack is 20°. Besides, the locally refined nodes distribution of spatial domain is to globally reduce the computing resource. © 2021, Science Press. All right reserved.
Keyword :
Airfoils Angle of attack Neural networks Reynolds number Unsteady flow
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GB/T 7714 | Wang, Tong-Sheng , Sun, Zhong-Guo , Huang, Zhu et al. Reconstruction of Fluid Flows Past Airfoils Using Neural Network [J]. | Journal of Engineering Thermophysics , 2021 , 42 (5) : 1205-1212 . |
MLA | Wang, Tong-Sheng et al. "Reconstruction of Fluid Flows Past Airfoils Using Neural Network" . | Journal of Engineering Thermophysics 42 . 5 (2021) : 1205-1212 . |
APA | Wang, Tong-Sheng , Sun, Zhong-Guo , Huang, Zhu , Xi, Guang . Reconstruction of Fluid Flows Past Airfoils Using Neural Network . | Journal of Engineering Thermophysics , 2021 , 42 (5) , 1205-1212 . |
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In this paper, a finite volume WENO scheme on OpenFOAM, which can achieve arbitrary high order and be applied to unstructured grids, is used to simulate the viscous shock tube. The simulation is conducted on structured grids and triangular unstructured grids, in which the third-order and fourth-order WENO schemes are used to discretize the convection term. The results show that the accuracy and efficiency of the scheme on triangular unstructured grids are better than that on structured grids, and the efficiency of the third-order WENO scheme is higher than that of the fourth-order scheme. This work shows that the third-order WENO scheme with unstructured grids on OpenFOAM has more advantages and application potential in the simulation of complex flow fields such as internal flow of turbomachinery. © 2021, Science Press. All right reserved.
Keyword :
Efficiency Shock tubes
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GB/T 7714 | Chai, De-Lin , Xi, Guang , Sun, Zhong-Guo . Simulations of the Viscous Shock Tube With Finite Volume WENO Schemes [J]. | Journal of Engineering Thermophysics , 2021 , 42 (1) : 115-120 . |
MLA | Chai, De-Lin et al. "Simulations of the Viscous Shock Tube With Finite Volume WENO Schemes" . | Journal of Engineering Thermophysics 42 . 1 (2021) : 115-120 . |
APA | Chai, De-Lin , Xi, Guang , Sun, Zhong-Guo . Simulations of the Viscous Shock Tube With Finite Volume WENO Schemes . | Journal of Engineering Thermophysics , 2021 , 42 (1) , 115-120 . |
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The preliminary design and analysis methods of single-stage mixed-flow/centrifugal compressors were studied on the basis of the two-zone model, and the accuracy of the improved ODP problem iterative method based on SOA-TEIS mixed diffusion model in the preliminary design and analysis of the mixed-flow/centrifugal compressor was verified. The one-dimensional design and analysis of Krain high specific speed impeller and low specific speed impeller models were carried out using this method, and the results were compared with experimental data. The results show that the method presented in this paper could reduce the dependence on engineering experience parameter selection, and achieve accurate preliminary design calculations and off-design point performance predictions for mixed-flow/centrifugal compressors. The method was easy to implement programmatically, and the isentropic efficiency prediction deviation of the operating conditions near the design point obtained by the passive slip factor calculation method was within 1%. © 2021, Science Press. All right reserved.
Keyword :
Compressors Design Impellers Iterative methods
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GB/T 7714 | Tang, Yong-Hong , Wang, Zhi-Heng , Ji, Cheng et al. Research on Preliminary Design and Analysis Method of Mixed-flow/Centrifugal Compressor [J]. | Journal of Engineering Thermophysics , 2021 , 42 (2) : 393-398 . |
MLA | Tang, Yong-Hong et al. "Research on Preliminary Design and Analysis Method of Mixed-flow/Centrifugal Compressor" . | Journal of Engineering Thermophysics 42 . 2 (2021) : 393-398 . |
APA | Tang, Yong-Hong , Wang, Zhi-Heng , Ji, Cheng , Xi, Guang . Research on Preliminary Design and Analysis Method of Mixed-flow/Centrifugal Compressor . | Journal of Engineering Thermophysics , 2021 , 42 (2) , 393-398 . |
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The propagation characteristics of inlet total-pressure distortion in a centrifugal compressor are investigated by fullannulus unsteady three-dimensional numerical simulation. The inlet distortions considered in the paper are the total-pressure distortions covering a 60-deg sector (60deg distortion) and three 20-deg sectors (3∗20deg distortion), respectively. One is the classical distortion form, and the other is to simulate the downstream flow of the axial section of a centrifugal-axial combined compressor. By analyzing the distributions of flow parameters, the propagation of the total-pressure distortion in the centrifugal compressor is interpreted. The results show that, with the distortion propagating to the downstream, the lowpressure region produces a phase deviation along the streamwise direction relative to the opposite direction of impeller rotation direction, and the range of distortion region is reduced. Additionally, the propagation of the inlet distortion makes the three-dimensional characteristics of airflow more complex. The flow angle increases with different amplitudes along the direction of blade height corresponding to the distorted sector. The distortion region affects the location of blades which are in a low-pressure area, and the intensity of the distortion affects the increase of the flow angle. The distortion region causes more local relative flow losses, especially near the leading edge of blade suction surface. © 2021 American Society of Mechanical Engineers (ASME). All rights reserved.
Keyword :
Centrifugal compressors Centrifugation
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GB/T 7714 | Wang, Mingyi , Wang, Zhiheng , Xi, Guang et al. Numerical investigation on propagation characteristics of inlet total-pressure distortion in a centrifugal compressor [C] . 2021 . |
MLA | Wang, Mingyi et al. "Numerical investigation on propagation characteristics of inlet total-pressure distortion in a centrifugal compressor" . (2021) . |
APA | Wang, Mingyi , Wang, Zhiheng , Xi, Guang , Li, Yurun . Numerical investigation on propagation characteristics of inlet total-pressure distortion in a centrifugal compressor . (2021) . |
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In this paper, a numerical model of gas flow, heat transfer, mass transfer and electrochemical reaction multi-physics field coupling of a planar SOFC is established and solved. According to the calculation results, the distribution of velocity, temperature and concentration inside the SOFC cell is analyzed. The influence of cathode inlet flow rate, porosity, rib width and other parameters on the performance of SOFC is also discussed. The results show that within a certain range, increasing the cathode inlet flow rate can significantly increase the average current density of the cell. Increasing the porosity of the electrode can improve the gas diffusion of the porous electrode, thereby increasing the rate of the electrochemical reaction. Increasing the width of the ribs will result in a significant decrease in cell performance. Therefore, the rib width should be reduced as much as possible within the allowable range to optimize the working performance of the cell.
Keyword :
multiphysics coupling parameter study physical fields distribution solid oxide fuel cells work performance
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GB/T 7714 | Dang Zheng , Shen Xin , Ma Jinyan et al. Multiphysics Coupling Simulation and Parameter Study of Planar Solid Oxide Fuel Cell. [J]. | Frontiers in chemistry , 2021 , 8 . |
MLA | Dang Zheng et al. "Multiphysics Coupling Simulation and Parameter Study of Planar Solid Oxide Fuel Cell." . | Frontiers in chemistry 8 (2021) . |
APA | Dang Zheng , Shen Xin , Ma Jinyan , Jiang Zhaoyi , Xi Guang . Multiphysics Coupling Simulation and Parameter Study of Planar Solid Oxide Fuel Cell. . | Frontiers in chemistry , 2021 , 8 . |
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Previous publications have summarized that three special morphological structures of owl wing could reduce aerodynamic noise under low Reynolds number flows effectively. However, the coupling noise-reduction mechanism of bionic airfoil with trailing-edge serrations is poorly understood. Furthermore, while the bionic airfoil extracted from natural owl wing shows remarkable noise-reduction characteristics, the shape of the owl-based airfoils reconstructed by different researchers has some differences, which leads to diversity in the potential noise-reduction mechanisms. In this article, three kinds of owl-based airfoils with trailing-edge serrations are investigated to reveal the potential noise-reduction mechanisms, and a clean airfoil based on barn owl is utilized as a reference to make a comparison. The instantaneous flow field and sound field around the three-dimensional serrated airfoils are simulated by using incompressible large eddy simulation coupled with the FW-H equation. The results of unsteady flow field show that the flow field of Owl B exhibits stronger and wider-scale turbulent velocity fluctuation than that of other airfoils, which may be the potential reason for the greater noise generation of Owl B. The scale and magnitude of alternating mean convective velocity distribution dominates the noise-reduction effect of trailing-edge serrations. The noise-reduction characteristic of Owl C outperforms that of Barn owl, which suggests that the trailing-edge serrations can suppress vortex shedding noise of flow field effectively. The trailing-edge serrations mainly suppress the low-frequency noise of the airfoil. The trailing-edge serration can suppress turbulent noise by weakening pressure fluctuation.
Keyword :
flow control noise reduction owl trailing-edge serration
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GB/T 7714 | Li, Dian , Liu, Xiaomin , Wang, Lei et al. Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations [J]. | PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING , 2021 , 235 (14) : 2003-2016 . |
MLA | Li, Dian et al. "Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations" . | PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING 235 . 14 (2021) : 2003-2016 . |
APA | Li, Dian , Liu, Xiaomin , Wang, Lei , Hu, Fujia , Xi, Guang . Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations . | PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING , 2021 , 235 (14) , 2003-2016 . |
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The shrouded and unshrouded impellers are two typical kinds of impellers, which are widely utilized in centrifugal compressors of various applications. Centrifugal compressors with unshrouded impellers are generally recognized to display inferior performance to the shrouded impellers with the same geometry. In this paper, a comparative experiment shows some results inconsistent with conventional cognition. Measured performance indicates that the peak efficiency of the centrifugal compressor with an unshrouded impeller is higher than the shrouded one, where the two impellers have the same geometry of meridional profile and blade central plane, and matched the same vaneless diffuser and volute. In order to explore the causes of this divergence, the effects of factors such as blade thickness, surface roughness of components, tip clearance and sealing leakage characteristics on performance are analyzed by CFD code. Numerical results show that reasonable reduction in the blade thickness and improvement on the surface quality of the impeller could effectively increase the peak efficiency and the choke mass flow rate of the shrouded impeller. The unshrouded impeller with arbitrary blade surfaces would be deformed under the action of centrifugal force to achieve a small tip clearance during operation, and then obtains higher efficiency at design speed. The research results are helpful to evaluate the performance potential and sensitive design parameters of shrouded and unshrouded impellers. © 2021 American Society of Mechanical Engineers (ASME). All rights reserved.
Keyword :
Centrifugal compressors Centrifugation Computational fluid dynamics Efficiency Impellers Surface roughness Turbomachinery
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GB/T 7714 | Xi, Guang , Zhao, Chenxi , Tang, Yonghong et al. Comparison study on stage performance of centrifugal compressors with shrouded and unshrouded impellers [C] . 2021 . |
MLA | Xi, Guang et al. "Comparison study on stage performance of centrifugal compressors with shrouded and unshrouded impellers" . (2021) . |
APA | Xi, Guang , Zhao, Chenxi , Tang, Yonghong , Wang, Zhiheng . Comparison study on stage performance of centrifugal compressors with shrouded and unshrouded impellers . (2021) . |
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Dealing with complex geometry boundaries is a challenge for particle boundary conditions. Since the effective area of the fluid particle is cut off by the boundary, it is difficult to obtain accurate results near the boundary, especially for complex geometry shapes. Things become more complicated when dealing with multiple sizes of particles in multi-resolution particle methods. In this paper, a generic smoothed wall (GSW) boundary is proposed by using single layer particles to accurately discretize the boundary. The boundary weight function is transformed to a distance function to fill the vacancy of the particle number density of fluid particles. The GSW boundary can be applied in the static, moving and non-linear deforming wall conditions. It also can be used to effectively handle complex geometric boundaries, since simulation results are not affected by changes in the number and size of wall particles. In addition, the GSW boundary also shows good results when combined with multi-resolution methods solving problems with multiple sizes of particles. In this paper, the MPS–DEM coupling method with GSW boundary model is applied to solve non-linear FSI problem. Several cases have been calculated to validate the accuracy, convergency and stability of the GSW boundary model. Compared with dummy particle boundary, results show that the proposed GSW boundary model can improve the numerical accuracy near the boundary, and handle arbitrary moving boundaries with high efficiency. © 2021 Elsevier B.V.
Keyword :
Computational methods Computer applications Geometry
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GB/T 7714 | Sun, Yijie , Xi, Guang , Sun, Zhongguo . A generic smoothed wall boundary in multi-resolution particle method for fluid–structure interaction problem [J]. | Computer Methods in Applied Mechanics and Engineering , 2021 , 378 . |
MLA | Sun, Yijie et al. "A generic smoothed wall boundary in multi-resolution particle method for fluid–structure interaction problem" . | Computer Methods in Applied Mechanics and Engineering 378 (2021) . |
APA | Sun, Yijie , Xi, Guang , Sun, Zhongguo . A generic smoothed wall boundary in multi-resolution particle method for fluid–structure interaction problem . | Computer Methods in Applied Mechanics and Engineering , 2021 , 378 . |
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A novel combined cooling and power system integrating Solid Oxide Fuel Cell (SOFC), Supercritical CO2 (SCO2) partial heating cycle, and ejector refrigeration cycle is proposed, and the energy, exergy, exergoeconomic, and environmental analysis is performed to evaluate the system performance comprehensively. The parametric analysis is conducted to investigate the effects of six thermodynamic variables (i.e. fuel flow rate, excess air ratio, fuel utilization factor, turbine inlet temperature, SCO2 cycle pressure ratio, and SCO2 cycle split ratio) on the system performance. The results indicate that the lower total product unit cost conflicts with the higher thermodynamic efficiencies and lower CO2 specific emission. Therefore, multi-objective optimization is carried out to obtain a trade-off among thermodynamic, exergoeconomic, and environmental performances. Under the optimal condition, the exergy efficiency, total product unit cost, and CO2 specific emission of the system are 63.77%, 36.37 $/GJ, and 298.77 g/kWh respectively, and the system can achieve the power output of 168.95 kW and cooling output of 12.48 kW. The SOFC accounts for the largest part (15.72%) of the total exergy destruction and achieves the highest cost rate (6.90 $/h) with a high exergoeconomic factor of 90.90%, indicating its capital investment can be reduced for improving system cost-effectiveness. © 2021 Elsevier Ltd
Keyword :
Carbon dioxide Cost effectiveness Economic and social effects Ejectors (pumps) Environmental management Exergy Investments Multiobjective optimization Refrigeration Solid oxide fuel cells (SOFC)
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GB/T 7714 | Zhong, Like , Yao, Erren , Zou, Hansen et al. Thermo-economic-environmental analysis of an innovative combined cooling and power system integrating Solid Oxide Fuel Cell, Supercritical CO2 cycle, and ejector refrigeration cycle [J]. | Sustainable Energy Technologies and Assessments , 2021 , 47 . |
MLA | Zhong, Like et al. "Thermo-economic-environmental analysis of an innovative combined cooling and power system integrating Solid Oxide Fuel Cell, Supercritical CO2 cycle, and ejector refrigeration cycle" . | Sustainable Energy Technologies and Assessments 47 (2021) . |
APA | Zhong, Like , Yao, Erren , Zou, Hansen , Xi, Guang . Thermo-economic-environmental analysis of an innovative combined cooling and power system integrating Solid Oxide Fuel Cell, Supercritical CO2 cycle, and ejector refrigeration cycle . | Sustainable Energy Technologies and Assessments , 2021 , 47 . |
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