检索结果-内蒙古大学图书馆

Optimum design parameters for a venturi-shaped roof to maximize the performance of building-integrated wind turbines

引用

APPLIED ENERGY 2024年 355卷

作者： Ye, Xiulan Zhang, Xuelin Weerasuriya, A. U. Hang, Jian Zeng, Liyue Sun Yat Sen Univ Sch Atmospher Sci Southern Marine Sci & Engn Guangdong Lab Zhuhai Zhuhai Peoples R China Sun Yat Sen Univ Key Lab Trop Atmosphere Ocean Syst Minist Educ Zhuhai 519000 Peoples R China Sun Yat Sen Univ Guangdong Prov Key Lab Climate Change & Nat Disast Zhuhai Peoples R China Hong Kong Metropolitan Univ Sch Sci & Technol Dept Construct & Qual Management Ho Man Tin Hong Kong Peoples R China Chongqing Univ Dept Civil Engn Chongqing Peoples R China Hong Kong Univ Sci & Technol Dept Civil & Environm Engn Hong Kong Peoples R China

Venturi-shaped roofs provide advantageous wind conditions for efficiently operating building-integrated wind turbines without losing usable floor area. Despite these advantages, venturi-shaped roofs have been sparsely adopted for buildings due to the lack of understanding of their optimum designs to maximize the performance of building-integrated wind turbines. For the first time in literature, this study investigated four design parameters: support structure, corner modification, tunnel shape, and wind turbine arrangement to estimate the optimum venturi-shaped roof design by conducting computational fluid dynamics (CFD) simulations. The results revealed the advantages of shorter support structures with convex and concave shapes at upwind and downwind ends, creating high wind speeds with low turbulence intensities. Corner modifications to the tunnel's entrance and exit are vital to suppress flow separation at the tunnel's entrance and uniform distributions of wind speed and pressure. This study recommends aerodynamic tunnel shapes that follow a non-uniform rational B-spline (NURBS) to accelerate wind without increasing turbulence intensities. The optimum design parameters performed better in normal and oblique wind directions, confirming their universal applicability. This study proposes integrating all optimum design parameters into a venturi-shaped roof design to alleviate the adverse effects of support structures, which are essential for a stable roof design.

关键词： Venturi-shaped roof Building-integrated wind turbine computational fluid dynamics simulation Urban wind energy

来源：评论

学校读者我要写书评

暂无评论

A two-level optimisation approach for underground natural ventilation based on CFD and building energy simulations

引用

ENERGY AND BUILDINGS 2024年 310卷

作者： Wen, Yueming Wei, Jinxi Lau, Siu-Kit Gu, Zhenhong Leng, Jiawei Zhengzhou Univ Sch Architecture Zhengzhou 450001 Peoples R China Deakin Univ Sch Architecture & Built Environm Geelong Vic 3220 Australia Natl Univ Singapore Dept Architecture Singapore 117566 Singapore Southeast Univ Sch Architecture 2 Sipailou Nanjing 210096 Jiangsu Peoples R China Southeast Univ Nanjing Urban Planning Design Inst Nanjing 210096 Peoples R China

Natural ventilation is a historical and promising passive design for conserving building energy. However, a noticeable scarcity exists in design strategies and academic studies on underground natural ventilation. This study introduces a two-level optimisation approach for underground natural ventilation, considering form and environmental characteristics. At the initial level, computational fluid dynamics simulations were employed to quantify and visualise the momentary ventilation performances of various passive strategies. These simulations also furnished precise wind pressure coefficients. Subsequently, at the second level, this study predicted the annual energy savings of the proposed prototype by integrating an airflow network model with building energy simulations. To adapt design parameters, sensitivity analysis and multi-objective optimisation techniques were applied. These numerical models underwent validation against measured data from analogous studies. The results reveal that the 'inlet buried pipe + outlet shaft' led to a 6.9 % reduction in energy consumption for heating, ventilation, and air-conditioning in underground hybrid ventilation compared to underground mechanical ventilation. Moreover, it achieved a 28.8 % decrease compared to aboveground mechanical ventilation. Optimising air temperatures following climate, soil conditions, and building characteristics is imperative, aligning with design standards. This study contributes a quantitative and visual approach to support underground natural ventilation and addresses the limitations of empirical designs, providing a foundation for future research and practical applications.

关键词： Underground natural ventilation Performance prediction computational fluid dynamics simulation Building energy simulation Multi -objective optimization

来源：评论

学校读者我要写书评

暂无评论

Thermal assessments for design and active ventilation system of indoor dry storage facility of Chinshan Nuclear Power Plant

引用

NUCLEAR ENGINEERING AND DESIGN 2025年 431卷

作者： Wang, Wen-Yu You, Bo-Shuan Natl Kaohsiung Univ Sci & Technol Dept Energy & Refrigerating Air Conditioning Engn Kaohsiung 824 Taiwan Natl Univ Tainan Dept Greenergy Tainan 701 Taiwan

Dry storage of spent nuclear fuel (SNF) and the cooling of fuel assemblies are essential for the nuclear industry. SNF will be stored in concrete dry casks and an indoor dry storage facility at the Chinshan Nuclear Power Plant. In this study, Ansys Fluent is used to simulate the symmetric boundaries of thermal cases and the ventilation characteristics of eight vertical dry storage casks for SNF as cylinders in the studied dry storage facility. Incompressible ideal gas is adopted in the simulation, and the low Reynolds k-epsilon turbulence model is used. The following parameters are analyzed in this study: (i) different heat loads, (ii) different arrangements, (iii) accident conditions, and (iv) installation of an active ventilation system at the outlet position of the dry storage systems (DSSs) in the facility. The results show that the DSS heat load, half-blockages, and arrangements significantly influence the temperature distribution in the facility. Installing an active ventilation system at the outlet position affects the staff and significantly decreases the temperature distribution in the facility. It is recommended that the rotational fan speed be set at 600 to 750 rpm for future designs. The results provide future design guidelines for indoor dry storage facilities.

关键词： Active ventilation system Building design computational fluid dynamics simulation Chinshan Nuclear Power Plant Indoor dry storage

来源：评论

学校读者我要写书评

暂无评论

Elucidating the Electrochemical Corrosion of a Water Pump Impeller in an Industrial Cooling System with Zero Liquid Discharge

引用

WATER 2025年第2期17卷 173-173页

作者： Jarrahi, Mina Mousavi Khajavian, Ehsan Nezhad, Amir Hossein Noorbakhsh Zahrani, Ehsan Mohammadi Alfantazi, Akram Ferdowsi Univ Mashhad Fac Engn Dept Mat Sci & Engn Mashhad 91775 1111 Iran Khalifa Univ Sci & Technol Dept Chem Engn POB 2533 Abu Dhabi U Arab Emirates

The electrochemical corrosion of a single-suction centrifugal water pump impeller made of gray cast iron operating at 85 degrees C was investigated in two industrial water media, i.e., groundwater extracted from a borehole and treated wastewater. Open circuit potential (OCP) measurement plus potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques elucidated the electrochemical corrosion performance and inductively coupled plasma-optical emission spectroscopy (ICP-OES) characterized the water samples. The retired and brand-new impellers were studied using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and visual and metallographic examinations. Impeller trailing edges were vulnerable to corrosion damage due to increased total fluid pressure, velocity, and temperature. The groundwater was more contaminated with Ca, Mg, Na, Si, and S elements and possessed higher conductivity, pH, and suspended solids than the treated wastewater. The impeller was more susceptible to graphitic corrosion in the groundwater due to emerging microgalvanic cells. A kinetic control electrochemical mechanism was elucidated as the corrosion rate-controlling step in the wastewater. A mixed kinetic and diffusion control mechanism was predominant in the groundwater because a short Warburg impedance element emerged. This study showcased the significance of integrated industrial water management and treatment strategies to protect pumps' integrity and uptime in critical industrial units implementing a zero-liquid discharge program.

关键词： electrochemical corrosion gray cast iron computational fluid dynamics simulation EIS Warburg diffusion impedance centrifugal water pump zero liquid discharge cooling system

来源：评论

学校读者我要写书评

暂无评论

Mitigating near-surface polarizations in membrane distillation via membrane surface decoration

引用

DESALINATION 2024年 579卷

作者： Zhang, Yaoling Guo, Fei Dalian Univ Technol Sch Energy & Power Engn 2 Linggong Rd Dalian 116024 Peoples R China

Temperature and concentration polarizations near the membrane surface zone can significantly affect the performance of membrane distillation, resulting in reduced transmembrane flux and overall efficiency. The fundamental approach to mitigating near-surface polarizations involves enhancing turbulence flow near the membrane surface to minimize the formation of polarization layers. This study focuses on modifying the membrane surface via surface decoration to reduce the polarization layers. The effects of membrane surface decoration on the performance of membrane distillation were systematically investigated through an air gap membrane distillation module under various operating conditions. The hydrodynamic characteristics of the flow near the membrane surface were studied using computational fluid dynamics simulations. The characteristics of both bottom-up and top-down disturbing configurations were analyzed. In addition, we investigated the influence of various flow disturbing methods on the mass transfer coefficient in membrane distillation processes. The membrane distillation test results show that at feed temperatures of 50 degrees C and 70 degrees C, there are respective increases in transmembrane flux of 30 % and 12 %. The results provide insights into optimizing the flow state near the membrane surface for enhanced membrane distillation performance.

关键词： Membrane distillation Near -surface polarization Membrane surface decoration Bottom -up disturbance computational fluid dynamics simulation

来源：评论

学校读者我要写书评

暂无评论

computational fluid dynamics INVESTIGATION OF A NOVEL BI-DIRECTIONAL AXIAL FLOW TURBINE FOR WAVE ENERGY CONVERSION

COMPUTATIONAL FLUID DYNAMICS INVESTIGATION OF A NOVEL BI-DIR...

引用

ASME Power Conference (Power)

作者： Uddin, Mohammad Nasim Atkinson, Michael Das, Tapas K. Esau, Simon North Carolina A&T State Univ Greensboro NC 27411 USA Queens Univ Belfast Antrim North Ireland

ISBN: (纸本)9780791885826

Wave energy conversion devices incorporating the Oscillating Water Column (OWC) principle are the most extensively used wave energy converting technologies to date. In this paper, we explore the effect of a fixed blade Denniss-Auld turbine that is representative of the maximum pivot points which occur during OWC inhalation and exhalation. Whereas conventional Denniss- Auld turbines are mounted on an intricate hub system that allows for controlled blade rotation to optimize performance, we investigate the possibility of removing the mechanical complexity while maintaining good aerodynamic performance. The assessment of turbine performance is carried out using non-dimensional coefficients, i.e., torque, pressure drop, and efficiency. The simulations are completed by solving the incompressible, steady-state Reynolds Averaged Navier-Stokes (RANS) equations with the k-omega SST turbulence model using ANSYST CFX. Validation of our numerical approach was completed by comparing existing experimental and numerical data of a Wells turbine. Furthermore, a grid independence study was conducted to achieve accurate numerical results. Overall, the modified Denniss- Auld turbine does not stall at high flow coefficients and has an extended operating range similar to an impulse turbine;however, with a much lower maximum efficiency of 12%. Future work should explore a larger design space with blade optimization using parametric studies to improve device efficiency.

关键词： Oscillating Water Column Wells turbine computational fluid dynamics simulation Modified Denniss-Auld turbine Turbine blade aerodynamics

来源：评论

学校读者我要写书评

暂无评论

Toward Automatic Parabolized Stability Equation-Based Transition-to-Turbulence Prediction for Aerodynamic Flows

引用

AIAA JOURNAL 2021年第2期59卷 462-473页

作者： Olichevis Halila, Gustavo Luiz Fidkowski, Krzysztof J. Martins, Joaquim R. R. A. Univ Michigan Aerosp Engn Dept Ann Arbor MI 48109 USA

The inclusion of transition-to-turbulence effects in computational fluid dynamics simulations is essential to accurately predict drag reduction from the use of laminar flow technologies. The parabolized stability equation (PSE) method takes into account nonlocal and nonparallel effects on boundary-layer dynamics. Its computational cost compares to that of linear stability theory (LST) analysis, which does not account for these effects. However, difficulties related to the robustness of PSE have prevented its application to industrial cases, where the more straightforward LST approach has been adopted because of its relative ease of use. When using PSE with an eN transition method, it is necessary to determine the stability modes that trigger transition and their neutral points (NPs). A robust PSE-based transition framework is proposed that includes a boundary-layer solver, a database method, and an LST solver that provides the required stability modes and the corresponding NPs so that a robust PSE calculation is automatically performed. The current approach leverages an automatic framework for the application of PSE-based transition prediction to aerodynamic flow analysis.

关键词： Freestream Turbulence Natural Laminar Flow Parabolized Stability Equations Boundary Layer Thickness Aerodynamic Design computational fluid dynamics simulation Neutral Point Reynolds Averaged Navier Stokes NLF(1) 0416 Aircraft Configurations

来源：评论

学校读者我要写书评

暂无评论

Efficient prediction of unsteady piston winds in subway tunnels based on machine learning

引用

JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AEROdynamics 2025年 262卷

作者： Liu, Xue Liu, Jian Cao, Peng Wang, Yu Wang, Honglin Wang, Dong Liaoning Tech Univ Coll Safety Sci & Engn Huludao 125105 Liaoning Peoples R China Minist Educ Key Lab Mine Thermo mot Disaster & Prevent Huludao 125105 Liaoning Peoples R China Liaoning Tech Univ Liaoning Acad Mineral Resources Dev & Utilizat Tec Fuxin 123000 Peoples R China Liaoning Tech Univ Equipment Res Inst Fuxin 123000 Peoples R China

In emergencies such as fires in subway tunnels, the rapid prediction of piston winds therein is needed to provide theoretical guidance for emergency decision-making and fire rescue. Previous research has neglected the efficiency of piston wind prediction. For this reason, to improve on traditional methods, this paper uses eight different machine learning algorithms, including support vector regression (SVR), k-nearest neighbors (KNN), and extreme gradient boosting (XGBoost) et al., to construct a fast prediction model for unsteady piston winds in subway tunnels. A relatively optimal machine learning algorithm was determined through various evaluation methods, and feature importance analysis was carried out. The results show that it is feasible to utilize a machine-learning method for the fast prediction of unsteady piston winds in subway tunnels. The RF algorithm had a high prediction accuracy for unsteady piston winds, and the Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), Symmetric Mean Absolute Percentage Error (SMAPE), and Coefficient of Determination (R-2) of the prediction results were 0.04, 0.05, 1.15 %, and 0.995, respectively. The influence degree of each factor on the subway tunnel piston wind, in descending order, is as follows: time t>blockage ratio beta>train running speed u>tunnel length l(tu)>train length l(tr).

关键词： Piston wind Machine learning Fast prediction Subway tunnel computational fluid dynamics simulation

来源：评论

学校读者我要写书评

暂无评论

Parametric analysis of venturi-type microbubble generator and the bubble fragmentation dynamics

引用

DESALINATION AND WATER TREATMENT 2025年 322卷

作者： Zhou, Yi Cui, Jingyu Chen, Zhen Liu, Jiancong He, Lipeng Fan, Wei Huo, Mingxin Northeast Normal Univ Sch Environm 2555 Jingyue St Changchun 130117 Peoples R China Lversheng Chongqing Environm Technol Co Ltd Chongqing Peoples R China Changchun Univ Technol Sch Mechatron Engn Changchun 130012 Peoples R China

Venturi-type tubes facilitate efficient microbubble generation, enhancing gas-liquid mixing, mass transfer, and reactions in wastewater treatment. However, the demand for high transfer efficiency with low energy consumption necessitates advancements in the parametric analysis of generators. This study presents a novel microbubble generator that integrates a suction chamber with a Venturi system. Through a comprehensive analysis of suction performance, gas-phase transport modes, and bubble collapse kinetics, we analyzed structural parameters using computational fluid dynamics simulations. The effective design features a centrally positioned nozzle, an air inlet at 2 mm depth, and a 12.5 degrees divergence angle. simulations indicated that a single bubble at the throat of the generator undergoes significant kinetic energy reduction and pressure energy increase in the expansion section, leading to pronounced tearing and deformation from inhomogeneous turbulence, resulting in smaller bubbles reduced to approximately 1/20 of their initial volume. Based on these analysis results, a laboratory-scale bubble generator was constructed, with flow tests demonstrating bubble sizes under 300 mu m. Notably, the dissolved oxygen concentration in water treated by the generator was 12.6% above the saturated level, showcasing superior oxygen enrichment compared to traditional aeration methods. This study provides valuable insights for advancing micro- and nano-bubble generation technologies.

关键词： Venturi-type bubble generator Bubble fragmentation Microbubble computational fluid dynamics simulation

来源：评论

学校读者我要写书评

暂无评论

Modified calculation model of train-induced aerodynamic pressure on vertical noise barriers considering the train geometry effect

引用

JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AEROdynamics 2024年 249卷

作者： Liu, Dongyun Wang, Chao Gonzalez-Libreros, Jaime Tu, Yongming Elfgren, Lennart Sas, Gabriel Lulea Univ Technol Dept Civil Environm & Nat Resources Engn Div Struct & Fire Engn S-97187 Lulea Sweden Southeast Univ Natl Engn Res Ctr Prestressing Technol Sch Civil Engn Key Lab Concrete & Prestressed Concrete StructMin Nanjing 211189 Peoples R China

High-speed trains (HSTs) generate air disturbance, leading to significant aerodynamic pressure on the noise barriers. Differences in train geometry result in variations in the aerodynamic pressure on noise barriers, implying that existing European standard calculation models may not necessarily be suitable for all types of HSTs. In this paper, the influence of the width, height, and nose length of the train on the aerodynamic pressure on vertical noise barriers was studied using computational fluid dynamics (CFD) simulations. Results showed that taller and wider trains result in greater aerodynamic loads on noise barriers. Conversely, an increase in the nose length of a train leads to a reduction in such pressure. Using grey relational analysis, correlation of various factors with the train-induced aerodynamic pressure is, from strong to weak: distance to the track center, width, height, and nose length of the train. Building upon the EN 14067-4 calculation model, the shape coefficients of trains with varying geometric characteristics were derived using the simulation data obtained in this study. A modified pressure calculation model was established accounting for the differences in geometric features of HSTs and pressure distribution in the vertical direction of noise barriers and validated using relevant data from the literature.

关键词： Aerodynamic pressure computational fluid dynamics simulation Pressure calculation model Train geometry Vertical noise barrier

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：