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computational fluid dynamics simulation OF AIRFLOW PATTERNS AND PARTICLE DEPOSITION CHARACTERISTICS IN CHILDREN UPPER RESPIRATORY TRACTS

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ENGINEERING APPLICATIONS OF computational fluid MECHANICS 2012年第4期6卷 556-571页

作者： Liu, Zhijian Li, Angui Xu, Xiaoxia Gao, Ran Xian Univ Architecture & Technol Sch Environm & Municipal Engn Xian 710055 Shanxi Peoples R China

As findings from studies of airflow patterns and particle deposition in the upper respiratory tracts (URTs) of adults may not be readily extrapolated to studies of the URTs of children, due to the differences in airway anatomy and breathing conditions, the effects of pediatric, physiological features on airflow patterns and particle deposition have been investigated utilizing an idealized model of the URTs of children. Particle deposition characteristics in a 0.01-10 mm spectrum were assessed employing a well-verified, Lagrangian tracking method for different inhalation flow rates, consistent with sedentary (3.5 L/min), light (7.0 L/min) and high (10.5 L/min) activity levels. The main results are: (1) airflow patterns during inhalation and exhalation modes are very different, while airflow patterns are similar during each inhalation or exhalation mode, while subject to three different airflow rates;(2) higher Stokes and impaction numbers are observed in the model for a 3 year old child, when compared to adults under comparably scaled activity levels;and (3) breathing airflow rates, particle diameters and particle densities are three key factors influencing particle deposition rates, with higher deposition rates for children observed when compared to adults under comparable activity levels. For identical impaction parameters, all deposition rates for children are also higher. The localized particle deposition rates in the mouth cavity are similar for children and adults, while those in the larynx, pharynx, trachea and bronchi are higher for children than for adults. Results of this study demonstrate that differences do exist between children and adults in both airflow distribution and aerosol deposition characteristics. These differences should be taken into account in the determination of children's risk exposure levels for airborne toxicants.

关键词： children upper respiratory tract airflow patterns particle deposition rates Stokes number computational fluid dynamics simulation

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Integrated molecular and computational fluid dynamics study of CO2 mass transport mechanisms in carbon molecular sieve membranes

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SEPARATION AND PURIFICATION TECHNOLOGY 2025年 363卷

作者： Tognia, Meudjeu Hou, Mengjie Dong, Xinyu Li, Lin Wang, Hua Wang, Tonghua Dalian Univ Technol State Key Lab Fine Chem Dalian Key Lab Membrane Mat & Membrane Proc Grp Carbon Membranes & Porous MatSch Chem Engn Dalian 116024 Liaoning Peoples R China

This study investigates CO2 mass transport in carbon molecular sieve (CMS) membranes using an integrated approach combining molecular simulations and computational fluid dynamics (CFD). Two CMS membranes derived from 4,4 '-(4,4 '-isopropyldiphenyl-1,1 '-dioxy) diphenylamine-pyromellitic dianhydride (BAPP-PMDA) and p-phenylenediamine-pyromellitic dianhydride (PPDA-PMDA) are analyzed to understand their adsorption behavior, pore structure, and transport mechanisms. Molecular simulations reveal that BAPP-CMS membrane, with its higher porosity (19746.97 & Aring;3 free volume) and diverse functional groups, exhibits superior CO2 adsorption (1.45 mmol/g at 100 kPa) due to stronger electrostatic interactions. In contrast, PPDA-CMS, with a denser pore structure (10761.23 & Aring;3 free volume), shows lower CO2 uptake (0.42 mmol/g at 100 kPa) but higher selectivity (CO2/CH4 selectivity of 203, and CO2/N2 selectivity of 48.2). CFD simulations highlight distinct transport mechanisms: surface diffusion dominates in BAPP-CMS, enhancing permeability, while PPDA-CMS relies on molecular sieve diffusion, restricting larger gas molecules. The combined approach also reveals transport pathways, pore architecture, and connectivity, which are difficult to observe experimentally. These insights enable a deeper understanding of the interplay between adsorption, pore structure, and transport properties. The results highlight the value of using molecular simulations and CFD to optimize materials for CO2 capture and gas separation, offering a comprehensive view of the factors that influence membrane performance.

关键词： Molecular simulation computational fluid dynamics simulation Carbon molecular sieve membrane CO 2 transport Gas separation membrane

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Significantly enhanced energy efficiency through reflective materials integration in plant factories with artificial light

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APPLIED ENERGY 2025年第PartC期377卷

作者： Cai, Wenyi Li, Saiya Zha, Lingyan He, Junyi Zhang, Jingjin Bao, Hua Shanghai Jiao Tong Univ Univ Michigan Shanghai Jiao Tong Univ Joint Inst Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Sch Agr & Biol Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Global Inst Future Technol Shanghai 200240 Peoples R China

Plant factory with artificial light (PFAL) based on vertical farming is a promising technology for resourceefficient plant production, especially in urban areas or arid regions. However, the lighting system of PFAL requires a large amount of energy, which makes the total energy cost much higher than open-field and greenhouse farming. To address this issue, in this work, a cultivation system integrated with highly reflective materials is demonstrated in PFAL, which reduces light energy consumption by more than 36 %. A low-cost reflective film is fabricated with an overall reflectivity of 96.5 % in the entire photosynthetically active radiation spectrum. The effectiveness of this reflective film in reducing energy consumption is further demonstrated with optical simulation analysis and the corresponding computational fluid dynamics simulation based on an experimental cultivation rack. The corresponding field experiments of 3 different types of lettuce, Crunchy, Butterhead and Grand Rapids, under different light intensities are conducted in the cultivation unit. With reflective film properly installed, a 36 % reduction of light energy consumption is demonstrated while the dry weight and fresh weight still increase. An additional benefit is that the light reception area of lettuce becomes larger due to the more uniform lighting with the integration of reflective material. This work presents a simple yet reliable strategy for enhancing the energy efficiency in PFAL systems and can achieve the cost-effective daily production of lettuce with significantly reduced energy input.

关键词： Reflective material integration Plant factory with artificial light Energy-saving Optical model simulation computational fluid dynamics simulation

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Evolution, modeling and CFD simulation of biomass particles during gasification process: Principles, applications and prospects

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CHEMICAL ENGINEERING SCIENCE 2025年 302卷

作者： Yang, Zhao Hu, Qiang Chen, Yingquan Yang, Haiping Wang, Chi-Hwa Bi, Xiaotao T. Chen, Hanping Huazhong Univ Sci & Technol Sch Energy & Power Engn State Key Lab Coal Combust Wuhan 430074 Peoples R China Natl Univ Singapore Dept Chem & Biomol Engn Singapore 117585 Singapore Univ British Columbia Clean Energy Res Ctr Dept Chem & Biol Engn Vancouver BC V6T 1Z3 Canada

Biomass particle evolution during gasification process will influence the heat and mass transfer, conversion efficiency, gasification performance of biomass conversion. However, during gasification process, the biomass particle can be melted, crushed, and shrunk, which makes it very complex to understand the particle behavior as well as the diversiform original feedstock particle. This paper reviews the characterization, modeling, and simulation of biomass particle evolution during the gasification process. Firstly, the models for the non-spherical biomass particle are firstly reviewed, and then followed by the discussion of the shrinkage and fragmentation phenomena happened during gasification process. The application of those models for the CFD simulation of biomass gasification is also discussed to analyze the effect of the particle evolution behavior on biomass gasification. Finally, the current challenges and future perspectives of biomass particle evolution are analyzed. This comprehensive review provides valuable insights into particle behavior during the biomass gasification process.

关键词： Biomass gasification computational fluid dynamics simulation Particle Evolution Particle modeling

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The role of circular shield in improving the thermal efficiency of domestic gas stove

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CASE STUDIES IN THERMAL ENGINEERING 2025年 66卷

作者： Su, Mingze Lin, Yu Meng, Deqi Gao, Naiping Zhu, Tong Chen, Jiawei Zhang, Dingrui Li, Zhonghua Liu, Xiaowen Midea Grp Co Ltd Foshan 528311 Guangdong Peoples R China Tongji Univ Sch Mech Engn Shanghai 200092 Peoples R China

Domestic gas stoves are widely used in the world as they are cheap and easy to use, therefore their thermal efficiency is one of the important factors affecting the great task of energy conservation and emission reduction. Installing a circular shield is the simplest and effective way to improve the thermal efficiency of domestic gas stove, but there is still no consensus on the role of installing a circular shield. In this paper, computational fluid dynamics simulations were carried out to mimic the testing process of the thermal efficiency of domestic gas stove. Based on the simulation results, thermodynamic analysis was then conducted to determine the heat distribution in each heat transfer pathway. By means of the thermodynamic analysis, the main role of circular shield in improving the thermal efficiency of domestic gas stove was finally elucidated. The role can be expressed as: the circular shield establishes a radiation heat transfer pathway from the circular shield to the bottom wall of the pot, and through this pathway, the circular shield transfers heat absorbed from the flue gas to the bottom wall of the pot. The clarification of the above mechanism is helpful for the further optimization of circular shield.

关键词： Domestic gas stove Circular shield Thermal efficiency Thermodynamic analysis computational fluid dynamics simulation

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Enhancing high-density battery performance through innovative single-phase spray technology in immersion cooling systems

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JOURNAL OF POWER SOURCES 2025年 626卷

作者： Shi, Hong Zeng, Zhuo Kong, Benben Yuan, Nenglin Jiangsu Univ Sci & Technol Coll Energy & Power Engn Zhenjiang 212003 Peoples R China Nanjing Univ Aeronaut & Astronaut Key Lab Aircraft Environm Control & Life Support MIIT Nanjing 210016 Peoples R China

The flow field organization in liquid-cooled BTMS (Battery Thermal Management System) is crucial to the thermal performance of lithium-ion batteries. This study introduces an innovative single-phase spray technology to optimize the flow field and enhance thermal characteristics in BTMS. Using computational fluid dynamics simulations, key factors such as dielectric fluid type, nozzle diameter, spray angle, and nozzle position are analyzed. Novec 7500 is identified as the optimal dielectric fluid, with thermal conductivity and viscosity playing significant roles. Response Surface Analysis and the entropy weight TOPSIS (Technique for Order of Preference by Similarity to the Ideal Solution) determine optimal conditions: a 0.47 mm nozzle diameter, 0 mm nozzle offset, and an 88.16 degrees spray angle. These parameters reduce the maximum battery temperature to 25.43 degrees C and minimize the temperature gradient to 3.41 degrees C, achieving reductions of 14.20 % and 57.74 %, respectively, compared to non-spray systems. Furthermore, the system reduces the maximum temperature of a 36-cell battery module by 27.28 % to 25.33 degrees C and the maximum temperature difference by 69.39 % to 4.35 degrees C. The optimized spray cooling technology is effective for smaller battery stacks and demonstrates the potential to maintain high cooling efficiency in complex systems, providing a solution for BTMS.

关键词： Single-phase spray Immersion cooling computational fluid dynamics simulation Response surface analysis Entropy weight TOPSIS

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

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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

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The impact of the wind attack angle on a typical bridge deck's flutter behavior by the distributed aerodynamic characteristics method

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JOURNAL OF VIBRATION AND CONTROL 2024年第3-4期30卷 727-739页

作者： Li, Ke Yang, Qingshan Wang, Xianmeng Li, Shaopeng Hui, Yi Fang, Genshen Qian, Guowei Chongqing Univ Key Lab New Technol Construct Cities Mt Area Minist Educ Chongqing Peoples R China Chongqing Univ Sch Civil Engn Chongqing Peoples R China Chongqing Key Lab Wind Engn & Wind Energy Utilizat Chongqing Peoples R China Tongji Univ State Key Lab Disaster Reduct Civil Engn Shanghai Peoples R China Univ Tokyo Sch Engn Dept Civil Engn Bunkyo Ku Tokyo Japan Chongqing Univ Sch Civil Engn 83 Shabei St Chongqing 400045 Peoples R China

To investigate the influence of the wind attack on a bridge deck's flutter performance, the concept of "pressure flutter derivatives" was introduced as a part of the "distributed aerodynamic characteristics" method, which can be used to visualize the dominant fluctuations of the pressure field. The distributions of the aerodynamic damping and stiffness under different wind attack angles were visualized, instead of using an overall force perspective. The analysis was carried out through two-dimensional computational fluid dynamics simulations based on a typical box deck section. Necessary data were obtained through the forced vibrations of the deck. The dominant pressure fluctuations were demonstrated, around which the wind attack angles' impact on the Scanlan flutter derivatives was discussed. For the deck section used in this study, the wind attack angle was found to most affect the windward parts of the deck. When wind attack angle ranged from -1.5 degrees to 3 degrees, two regions contributed the most: one located behind the windward faring vertex and the other located behind the first vertex of the upper slab. When the wind attack angle decreased to -3 degrees, a new dominant region appeared behind the first vertex of the lower slab, which caused a sudden reduction of the flutter critical speed.

关键词： Bridge aerodynamics wind attack angle aerodynamic damping distributed aerodynamic characteristics method computational fluid dynamics simulation

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Odour-sensitive passenger comfort in small aircraft cabins

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AERONAUTICAL JOURNAL 2024年第1321期128卷 429-440页

作者： Nasoulis, C. P. Mantziou, S. Gkoutzamanis, V. G. Kalfas, A. I. Aristotle Univ Thessaloniki Dept Mech Engn Lab Fluid Mech & Turbomachinery Thessaloniki Greece

This work presents a numerical investigation targeting to simulate the slice of a small aircraft cabin as an experimental facility with a controlled environment, to assess passenger comfort when exposed to high volatile organic compound (VOC) concentrations. The mixing and transport of chemical species are evaluated using computational fluid dynamics for 800 s of in-cabin actual flow time and measurements are taken every 10 s from selected computational nodes close to the passengers' noses. The results are used to create a dataset that trains four different machine learning classifiers, namely, the Random Forest, Support Vector Machine, Logistic Regression and Naive Bayes, and their performance is compared. Moreover, an additional simulation of the cabin with a filtering system utilising high-efficiency particulate air and activated carbon filters is conducted, to evaluate the impact of the molecular weight of the compounds on their residence time, and compare it to the simulation without the filters. Results indicate that the model is insensitive to the inlet air mass flow variation and that the mass of the VOCs measured in the monitored computational nodes remains relatively unaffected, meaning that the impact of the air-conditioning system setting is minor. Additionally, a Boruta feature selection algorithm is used to determine the importance of each measurement of the simulation and to form a dataset that will train the four machine learning classifiers. Furthermore, the comparison of the two simulations, the one with and the one without the filters, indicates that the residence time (RT) of the compounds is independent of their molecular weight, as they all show equivalent percentile reductions, with the naphthalene and styrene showing a 28.5% and 28.3% reduction respectively, compared to the simulation without the filters. Finally, in-cabin flow irregularities are present, disrupting the flow symmetry and suggesting that not all passengers share the same trave

关键词： Aircraft cabin environment Volatile organic compounds (VOCs) concentration computational fluid dynamics simulation Passenger comfort

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

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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

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