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A coupled cfd simulation approach for investigating the pyrolysis process in industrial naphtha thermal cracking furnaces

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Chinese Journal of Chemical Engineering 2022年第4期35卷 528-542页

作者： Mohsen Rezaeimanesh Ali Asghar Ghoreyshi S.M.Peyghambarzadeh Seyed Hassan Hashemabadi Chemical Engineering Department Babol Noshirvani University of TechnologyShariati Ave.47148-71167 BabolIran Department of Chemical Engineering Mahshahr BranchIslamic Azad UniversityMahshahrIran Computational Fluid Dynamics(cfd)Research Laboratory School of ChemicalPetroleum and Gas EngineeringIran University of Science and Technology(IUST)TehranIran

In the steam thermal cracking of naphtha,the hydrocarbon stream flows inside tubular reactors and is exposed to flames of a series of burners in the *** this paper,a full three-dimensional computational fluid dynamics(cfd)model was developed to investigate the process variables in the firebox and reactor coil of an industrial naphtha *** comprehensive cfd model consists of a standard k-εturbulence model accompanied by a molecular kinetic reaction for cracking,detailed combustion model,and radiative *** order to improve the steam cracking performance,the model is solved using a proposed iterative *** respect to temperature,product yield and specially propylene-toethylene ratio(P/E),the simulation results agreed well with industrial data obtained from a mega olefin plant of a petrochemical *** deviation of P/E results from industrial data was less than 2%.The obtained velocity,temperature,and concentration profiles were used to investigate the residence time,coking rate,coke concentration,and some other *** coke concentration at coil exit was1.9×10^(-3)%(mass)and the residence time is calculated to be 0.29 *** results can be used as a scientific guide for process engineers.

关键词： Naphtha thermal cracking cfd modeling Systems engineering Residence time Product yield

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Comparison of two-and three-dimensional modeling of invert trap for sewer solid management

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Particuology 2008年第3期6卷 176-184页

作者： Tsewang Thinglas Deo Raj Kaushal Civil Engineering Department IIT DelhiHauz KhasNew Delhi 110016India

In the present study, five different invert trap configurations （rectangular with and without lids on both sides; trapezoidal, trapezoidal with rectangular base and rectangular with trapezoidal base with lids on both sides） were simulated for both two-dimensional （2D） and three-dimensional （3D） flow conditions for three sediment types （sand, styrocell and plastic beads） at six flow rates （0.35, 0.70, 1.05, 1.35, 4.55 and 9.95 L/s） for each trap. Computational fluid dynamics （cfd）-based modeling using FLUENT software with Renormalization Group （RNG） k-e model along with discrete phase model （DPM） were used in the simulations. A hexagonal/tetrahedral and map-type non-uniform grid was chosen to discretize the entire computational domain and a control volume finite difference method was used to solve the governing equations. The flow rates selected in the present study cover the entire range of flow rate expected for dry weather and monsoon. The simulation is capable of differentiating between 2D and 3D modeling of particle trajectories, the effects of flow rate and trap geometry on flow patterns developed in the trap. The sediment retention ratio for 2D is higher than that for 3D modeling for all flow conditions, particle types and model geometry due to inclusion of lateral effects in 3D modeling. The invert trap having rectangular shape with trapezoidal base is found to be the most efficient configuration in both 2D and 3D modeling.

关键词： cfd modeling 2D 3D Invert trap Sediment trapping Urban drainage

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TRAFFIC EMISSION TRANSPORTATION IN STREET CANYONS

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Journal of Hydrodynamics 2009年第1期21卷 108-117页

作者： XIE Xiao-min WANG Jia-song HUANG Zhen Key Laboratory for Power Machinery and Engineering of State Education Ministry Shanghai Jiao Tong University Shanghai 200240 China

Spatial distributions of traffic-related pollutants in street canyons were investigated by field measurements and Computational Fluid Dynamics （cfd）. Two typical street canyons were selected for field monitoring, and a three-dimensional numerical model was built based on Reynolds-averaged Navier-Stokes equations equipped with the standard κ-ε turbulence models for cfd simulations. The study shows that the pollutant concentrations of vehicle emission correlate well with the traffic volume variation, wind direction and wind speed. The wind direction and speed at the roof level determine overwhellmingly the flow field and the distributions of pollutant concentrations in the street canyon. When the wind speed is equal to zero, the pollutant concentrations on the breath height of the both sides of the street canyon are almost the same. When the wind direction is perpendicular to the street, one main vortex is formed with a shape depending on the building structure on both sides of the street, the pollutant is accumulated on the leeward side, and the pollutant concentrations at the breath height on the leeward side are 2 to 3 times as those at the breath height on the windward side. If the wind direction makes some angles with the street canyon, the pollutant concentration will be higher on the leeward side because one main vortex will also be formed in the vertical section of the canyon by the perpendicular component of the wind. But pollutant concentrations decrease in the canyon because pollutants are dispersed along the axis of the street. Pollutants at different heights of the vertical section decrease with height, i.e. there are concentration gradients in the vertical section, and the pollutant concentrations on the leeward side of the upstream building are much higher than those on the windward side of the downstream building.

关键词： traffic emission street canyon field measurement cfd modeling

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Effects of window opening style on inside environment of solar greenhouse based on cfd simulation

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International Journal of Agricultural and Biological Engineering 2020年第6期13卷 53-59页

作者： Yachen Sun Encai Bao Chenmeng Zhu Lulu Yan Yanfei Cao Xuanhe Zhang Jianming Li Haiwei Jing Zhirong Zou Key Laboratory of Protected Horticultural Engineering in Northwest Ministry of AgricultureDepartment of HorticultureNorthwest A&F UniversityYangling 712100ShaanxiChina Institute of Agricultural Facilities and Equipment Jiangsu Academy of Agricultural ScienceKey Laboratory of Protected Agriculture Engineering in the Middle and Lower Reaches of Yangtze RiverMinistry of Agriculture and Rural AffairsNanjing 210014China College of Management City University of Hong KongTat Chee AvenueKowloon 999077Hong KongChina Department of Horticulture Xinyang Agriculture and Forestry UniversityXinyang 464000HenanChina Department of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100ShaanxiChina

Solar greenhouse is extensively used in horticultural production in *** ventilation is one of the key technological means to adjust the inside environment of greenhouse,while the effects of window opening styles on the inside environment are still not well *** the present study,the temperature and air flow field of five operation styles,namely back roof central opening style(G1),back roof evenly spaced opening style(G2),top roof full opening style(G3),style of G1+G3,and style of G2+G3 were simulated using the cfd *** results indicated that:(1)the simulated and measured results exhibited favorable agreement,with relative errors within 5%;(2)In the case of the windows opening area was the same and only single ventilation style was applied,back roof full opening style exhibited the best cooling *** inside average temperature of the greenhouse with G1 style decreased by 0.5°C and 1.6°C respectively compared with those of greenhouses with G2 and G3.(3)The cooling effect of the style of G2+G3 was more favorable than that of the style of G1+*** style of G2+G3 exhibited better cooling effect than the single ventilation styles,with the lowest temperature(27.5°C)and temperature uniformity coefficient(0.36).

关键词： cfd modeling window opening styles cooling effects solar greenhouse

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Design and Characterization of an Aerosol Test Chamber for Emergency Response Patient Contamination Control Simulation and Research

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Occupational Diseases and Environmental Medicine 2023年第1期11卷 78-96页

作者： Megan L. Steele Emily M. Spatz George P. Lemmer Jacob M. Denney Jeremy M. Slagley Casey W. Cooper Robert M. Eninger Fenic Ltd. Dayton USA Department of Systems Engineering and Management Air Force Institute of Technology Wright-Patterson Air Force Base Montgomery County USA Air Force Materiel Command Office of the Command Surgeon Wright-Patterson Air Force Base Montgomery County USA

Contaminated or infected patients present a risk of cross-contamination for emergency responders, attending medical personnel and medical facilities as they enter a treatment facility. The controlled conditions of an aerosol test chamber are required to examine factors of contamination, decontamination, and cross-contamination. This study presents the design, construction, and a method for characterizing an aerosol test chamber for a full-sized manikin on a standard North Atlantic Treaty Organization litter. The methodology combined air velocity measurements, aerosol particle counts and size distributions, and computational fluid dynamics modeling to describe the chamber’s performance in three dimensions. This detailed characterization facilitates future experimental design by predicting chamber performance for a variety of patient-focused research.

关键词： Test Chamber Characterization Aerosol Generation Exposure Chamber Design Air Velocity Mapping Spatial Variability cfd modeling Patient Decontamination

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