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Studies of Turbulent Heat Transfer Properties in Combined Solar Chimneys and Their engineering Applications

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SSRN 2023年

作者： Cui, Huimin Han, Mengjiao Zhang, Jitao Han, Zhiming Xu, Feng Liu, Qingkuan State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang050043 China Department of Mathematics and Physics Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China School of Physical Science and Engineering Beijing Jiaotong University Beijing100044 China

Solar chimneys can induce natural ventilation through solar radiation. However, sufficient theoretical studies are needed as a basis in order to fully exploit passive design in practical green building design. In this study, the heat transfer properties of turbulent natural convective flows in a combined solar chimney with a thermal flux at the absorption wall are investigated by theoretical analysis and numerical simulations. Two different flow patterns have been discovered, one with an obvious thermal boundary layer flow pattern and the other without, based on the high Rayleigh number. For the flow development in these two flow regimes, the transient scaling analysis is performed separately and the control mechanism for each phase is presented. Scaling correlations of air flow speed, temperature, and mass flow rate have been established to describe the ventilation properties of solar chimneys. The corresponding numerical simulation data is used for scaling verification. Ventilation times are calculated for a solar chimney with aspect ratio A=7.5 to provide a basis for the devise of a solar chimney. © 2023, The Authors. All rights reserved.

关键词： Boundary layers

A new control strategy for high speed train and its simulation analysis

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A new control strategy for high speed train and its simulati...

第八届国际振动工程会议

作者： Yiwei Zhao Shaopu Yang Yongqiang Liu Yingying Liao State Key Laboratory of Mechanical behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Department of Transportation Shijiazhuang Tiedao University Department of Mechanical Engineering Shijiazhuang Tiedao University Department of Civil Engineering Shijiazhuang Tiedao University

For a long time, the dynamic performance of high-speed train has been studied by many experts. And it will continue to be studied in the future with the rapid development of high-speed trains. The ride comfort and safety of trains which is the part of the dynamic performance is studied in this paper through applying the control method to the secondary lateral dampers and yaw dampers. Firstly, a train model is built by multi-body dynamics software UM. Then the co-simulation model is built in Simulink for the further study. The second, the multi-objective optimization for the damper damping coefficient of the secondary lateral dampers and yaw dampers is carried out in a straight track. The optimal damping coefficient that can improve the ride comfort and safety simultaneously is obtained. The objectives of optimization are the lateral acceleration and derailment coefficient. Similarly, the multi-objective optimization for the damping coefficient of the two kind of dampers is carried out in a curve track. The optimal damping coefficient is obtained. In order to keep the ride comfort and safety of the train, no matter in a straight track or in a curve track, the semi-active control method is proposed to adjust the damping coefficient. In this way, the damping coefficients of the two kinds of shock absorbers are always ***, the train model is simulated and *** results show that the control method that the two kinds of shock absorbers are controlled at the same time can significantly improve the ride comfort and safety of the train whether it's running in a straight track or a curve track. In other words,multi-point control can improve the train dynamic performance comprehensively.

关键词： high-speed train co-simulation semi-active ride comfort safety

Erratum: ‘Scattering of SH Waves Around Circular Canyon in Inhomogeneous Wedge Space’

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Geophysical Journal International 2021年第1期226卷 345-350页

作者： Zailin Yang Xinzhu Li Yunqiu Song Guanxixi Jiang Menghan Sun Xueqian Fang College of Aerospace and Civil Engineering Harbin Engineering University Harbin China Key Laboratory of Advanced Material of Ship and Mechanics Ministry of Industry and Information Technology Harbin Engineering University Harbin China sunmenghan163@*** State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

The Effects of Row Spacing and Ground Clearance On the Wind Load of Photovoltaic (Pv) Arrays

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SSRN 2023年

作者： Xu, Ang Ma, Wenyong Yuan, Huanxin Lu, Lihe State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang051132 China Key Laboratory of Road and Railway Engineering Safety Ministry of Education Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Hebei050043 China School of Civil Engineering Wuhan University Wuhan430072 China Inner Mongolia Electric Power Survey & Design Istitute Co. Ltd. Huhehot Inner Mongolia 010011 China

Row spacing and ground clearance have a significant effect on the wind load of a photovoltaic (PV) array. Based on wind tunnel tests and numerical simulations with the self-sustainable equilibrium atmospheric boundary layer, the influences of row spacing and ground clearance on the wind load of PV arrays are analysed, and the mechanism of the wind-induced interference effect is determined by flow field analysis. The results show that the ground clearance affects the wind load distribution on the PV module, and this effect has an inconsiderable impact on the net wind pressure on the PV modules. The effect of row spacing on the wind load of PV arrays is more significant, and this effect is mainly manifested in the shielding effect. The tilt angle is the main factor that affects the size of the vortex scale which significantly influences the wind load. The ground clearance, row spacing and tilt angle all affect the torque coefficient on the PV module. The larger the ground clearance is, the larger the torque coefficient. Finally, the wind load coefficients and reduction factors are presented as a recommendation for wind resistance design of PV arrays. © 2023, The Authors. All rights reserved.

关键词： Atmospheric boundary layer

Study on dynamic slaking response characteristics and calculation model of fouled ballast materials in heavy-haul railways

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Construction and Building Materials 2025年 481卷

作者： Yang, Zhihao Liu, Hengwen Deng, Xi Feng, Huaiping Chang, Jianmei Ma, Deliang Feng, Xiaoqing State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Traffic and Transportation Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

Investigating the dynamic slaking characteristics of fouled ballast is critical for elucidating the mud pumping mechanisms in heavy-haul railway ballasted track beds. In this study, in-situ fouled ballast materials from typical mud pumping sections were collected, and a series of dynamic slaking triaxial tests were conducted. The coupled effects of loading frequency, dynamic stress amplitude, and confining pressure on deformation behavior, water infiltration patterns, and moisture migration characteristics under dynamic slaking conditions were systematically examined. Moreover, the evolutionary mechanisms of softening indices in plastically creeping specimens were quantitatively analyzed, yielding computational models for both softening indices and accumulative plastic strain. Furthermore, based on the improved Iwan series model, a calculation model of the dynamic stress-strain relationship considering the load amplitude and frequency under dynamic slaking conditions was established. The dynamic slaking deformation mechanism of fouled ballast was discussed from three aspects: the hysteresis effect of dynamic slaking deformation, the critical frequency regulation mechanism, and the hydromechanical coupling and feedback laws. Based on the findings, a "frequency-amplitude" collaborative control strategy is proposed for mitigating mud pumping diseases in ballasted track beds. © 2025 Elsevier Ltd

关键词： Ballast (railroad track)

Study on the Band Gap and Directional Wave Propagation Mechanism of Novel Single-Phase Metamaterials

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SSRN 2022年

作者： Cheng, Shu-Liang Yang, Hong-Yun Yan, Qun Wang, Bin Sun, Yong-Tao Xin, Ya-Jun Ding, Qian Yan, Hao Wang, Liang Key Laboratory of Mechanical Reliability for Heavy Equipment and Large Structure of Hebei Province Yanshan University Qinhuangdao China Tianjin Key Laboratory of Soft Soils and Engineering Environment Tianjin Chengjian University Tianjin China Department of Mechanics Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin University Tianjin China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China Key Laboratory of Aeroacoustics and Dynamics Aircraft Strength Research Institute Xi’an China Key Laboratory of Green Construction and Intelligent Maintenance for Civil Engineering of Hebei Province Yanshan University Qinhuangdao China

In this paper, a new type of single-phase metamaterial is proposed. Based on the finite element method, the band gap characteristics of the structures with different branches are comprehensively analyzed, and the existence of the band gap is further verified by the frequency response transmission spectrum. Then, the propagation characteristics of elastic waves of different frequencies in different combinations of structures are investigated respectively. The results show that the proposed single-phase metamaterial structure has an excellent band gap range, and under the action of relatively low-frequency elastic waves, the wave propagation in the structure has a certain direction and regionality, while the elastic waves at higher frequencies are applied, the propagation direction of the wave tends to propagate in all directions. This paper provides a new idea for studying the structural design of metamaterials with specific wave propagation directions. © 2022, The Authors. All rights reserved.

关键词： Energy gap

Research on Brake Failure Control of Heavy Commercial Vehicles Based on Turning Conditions

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Research on Brake Failure Control of Heavy Commercial Vehicl...

Conference on Vehicle Control and Intelligence (CVCI)

作者： Yongjie Lu Fahui Wang Guangfeng Zhang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (数字)9781728184975

ISBN: (纸本)9781728184982

With the rapid rise of the transportation industry, commercial vehicles as an important means of transportation, its safety and stability are paid more and more attention. In order to improve the safety performance of heavy commercial vehicles when braking failure occurs under turning conditions. Based on the vehicle dynamics characteristics, this paper designed the stability control strategy in the case of brake failure in the above conditions, designed a fuzzy PID controller based on yurch angular velocity control, carried out the Trucksim-Simulink joint simulation and hardware in the loop experiment to jointly verify the control effect of the brake. The results show that the influence of vehicle brake failure on vehicle driving stability is reduced, the performance of vehicle brake under long and downhill conditions and turning conditions is improved, and the safety stability of vehicle brake failure in hardware loop is improved, which meets the requirements of national standards for vehicle braking.

关键词： Stability criteria Turning Hardware safety Brakes Acceleration Standards

Experimental Investigations on the Wind Load Interference Effects of Single-Axis Solar Tracker Arrays

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SSRN 2022年

作者： Ma, Wenyong Zhang, Weida Zhang, Xiaobin Chen, Wei Tan, Qiang School of Civil Engineering Shijiazhuang Tiedao University Hebei 050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Hebei 050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China Jiangsu Guoqiang Singsun Energy Co. Ltd 213300 China

Aiming at the interference effect of wind loads on single-axis solar tracker arrays, this study conducts rigid-model pressure measurement wind tunnel tests on a single-row solar tracker and solar tracker arrays. The effects of the tilt angle and wind direction on aerodynamic characteristics are examined. The basic characteristics of the wind-induced interference effects of a single-axis solar tracker array are clarified. The results reveal that when the tilt angle is small, the interference effect is small, the tilt angle increases, the interference effect becomes stronger. From the mean pressure and torque coefficients, the interference effect is mainly manifested as a shielding effect. Based on the fluctuating pressure and torque coefficients, the interference effect appears as a shielding effect and an amplification effect in small- and large-tilt angle ranges, respectively. The wind load power spectrum of the solar modules in the rear-row of the solar tracker arrays presents remarkable frequency peaks, and experiences stronger wind-induced vibrations than the front-row modules. The influence of the wind direction results in nonuniform distributions of wind loads along the length of the solar tracker. Thus, the enhancement in wind loads on the edge areas of solar arrays caused by the wind direction should be considered. © 2022, The Authors. All rights reserved.

关键词： Wind stress

Three-dimensional train-periodic slab track-subgrade dynamics model based on the iterative solution and Green's function method

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Computers and structures 2025年 315卷

作者： Sun, Yu Zhang, Sen Xing, Mengting Shi, Zhiyong Liu, Pengfei College of Transportation Engineering Nanjing Tech University Nanjing210009 China Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang Tiedao University Shijiazhuang050043 China College of Rail Transit Wuxi University Wuxi214105 China Department of Industrial Engineering University of Florence Florence50139 Italy State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China

This paper develops an iterative solution model for the efficient and accurate simulation of the dynamics of a three-dimensional (3D) train-periodic slab track-subgrade (TPSTS) system. The entire system is divided into the train-rail subsystem and the periodic slab-subgrade subsystem. An ordinary differential equation (ODE) model of the train-rail system is established, and a step-moving strategy is employed to enhance the computational efficiency. A frequency-domain Green's function method (GFM) model is employed for modelling the periodic slab-subgrade. Considering the periodicity, symmetry, and attenuation characteristics of the track structure, the Green's function of the slab-subgrade structure is obtained by conducting harmonic response analysis on a finite element model (FEM) of a quarter slab-subgrade structure. The proposed model is utilized to investigate the vibration characteristics of the high-speed train-track-subgrade system. The results indicate that the model exhibits good convergence, accuracy, and efficiency. The periodicity of the track structure has a significant impact on the statistical values of subgrade displacement and stress amplitudes along the track's longitudinal direction. At the subgrade surface, the amplitudes of displacement, stress, and acceleration exhibit fluctuations in the lateral direction of the track. However, with increasing depth, these amplitudes generally attenuate, leading to a more uniform distribution. © 2025 Elsevier Ltd

关键词： Railroad transportation