Numerical study of modeling methods and evaluation indexes for jet fans

2021 ◽  
pp. 108284
Author(s):  
Yu Xue ◽  
Xiaomeng Li ◽  
Zhichao Wang ◽  
Honglei Wang
Keyword(s):  
Numerical Study ◽  
Evaluation Indexes ◽  
Modeling Methods

Numerical Simulations of Turbulent Mixing and Autoignition of Hydrogen Fuel at Reheat Combustor Operating Conditions

2011 ◽  
Author(s):  
Elizaveta Ivanova ◽  
Berthold Noll ◽  
Peter Griebel ◽  
Manfred Aigner ◽  
Khawar Syed
Keyword(s):  
Natural Gas ◽  
Numerical Simulations ◽  
Flue Gas ◽  
Turbulent Mixing ◽  
Turbulence Modeling ◽  
Numerical Study ◽  
Operating Conditions ◽  
Fuel Blend ◽  
Flow Configuration ◽  
Modeling Methods

Turbulent mixing and autoignition of H2-rich fuels at relevant reheat combustor operating conditions are investigated in the present numerical study. The flow configuration under consideration is a fuel jet perpendicularly injected into a crossflow of hot flue gas (T > 1000K, p = 15bar). Based on the results of the experimental study for the same flow configuration and operating conditions two different fuel blends are chosen for the numerical simulations. The first fuel blend is a H2/natural gas/N2 mixture at which no autoignition events were observed in the experiments. The second fuel blend is a H2/N2 mixture at which autoignition in the mixing section occurred. First, the non-reacting flow simulations are performed for the H2/natural gas/N2 mixture in order to compare the accuracy of different turbulence modeling methods. Here the steady-state Reynolds-averaged Navier-Stokes (RANS) as well as the unsteady scale-adaptive simulation (SAS) turbulence modeling methods are applied. The velocity fields obtained in both simulations are directly validated against experimental data. The SAS method shows better agreement with the experimental results. In the second part of the present work the autoignition of the H2/N2 mixture is numerically studied using the 9-species 21-steps reaction mechanism of O’Conaire et al. [1]. As in the reference experiments, autoignition can be observed in the simulations. Influences of the turbulence modeling as well as of the hot flue gas temperature are investigated. The onset and the propagation of the ignition kernels are studied based on the SAS modeling results. The obtained numerical results are discussed and compared with data from experimental autoignition studies.

scholarly journals TA3 Numerical study of the evaluation indexes for outdoor pedestrian thermal comfort.

2006 ◽  
Vol 2006 (108) ◽  
pp. 509-528 ◽  
Author(s):  
Borong Lin ◽  
Yingxin Zhu ◽  
Xiaofeng Li ◽  
Youguo Qin ◽  
Shinji Yoshida ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Numerical Study ◽  
Evaluation Indexes

scholarly journals The use of mathematical modeling methods for solving geo-ecological problems of sustainable development of regions

2020 ◽  
Vol 161 ◽  
pp. 01005
Author(s):  
M V Volik
Keyword(s):  
Mathematical Modeling ◽  
Air Pollution ◽  
Sustainable Development ◽  
Numerical Study ◽  
Digital Technologies ◽  
Motor Vehicles ◽  
Gaseous Pollutants ◽  
Mathematical Apparatus ◽  
Modeling Methods ◽  
Ecological Problems

Currently, a number of environmental problems have a significant impact on the stable economic development of the country. A global problem is the study of air pollution. The solution of such geoecological problems should be carried out with the use of modern mathematical apparatus and digital technologies. The paper presents the results of a numerical study of the distribution of gaseous pollutants emitted by motor vehicles in the pedestrian zone of streets. It is shown that the vortex structures formed in the studied city buildings development have a significant impact on the accumulation of anthropogenic impurities.

scholarly journals Numerical Study on Optimal Scheme of the Geothermally Heated Bridge Deck System

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6633
Author(s):  
Weidong Lyu ◽  
Hefu Pu ◽  
Jiannan (Nick) Chen ◽  
Zelei Gao
Keyword(s):  
Ambient Temperature ◽  
Bridge Deck ◽  
Numerical Study ◽  
Concrete Cover ◽  
Evaluation Index ◽  
Inlet Temperature ◽  
Evaluation Indexes ◽  
Ground Source ◽  
Absorption Power ◽  
Synthetic Evaluation

Ground source deicing system application in bridge decks is an alternative to salt use, which reduces corrosion and extends the deck service life. Herein, a preliminary parametric numerical analysis is performed to investigate the effects of several important parameters (tube spacing, inlet temperature, flow rate, and concrete cover) on heat transfer performance. Three evaluation indexes (average top surface temperature, snow melting proportion, and heat absorption power) are introduced, and a synthetic evaluation index is proposed to comprehensively consider factors. Mainly referring to the synthetic evaluation index, the optimal design scheme of a geothermally heated bridge deck system under various conditions (layout, lane number, ambient temperature, and tube spacing) is obtained and analyzed to determine the optimal inlet temperature and guide heated bridge deck design. Finally, the influence of wind speed and two adjustment methods are studied. The results indicate that the horizontal layout is the recommended circulating tube layout. The established empirical equations reveal that the optimal inlet temperature is linearly related to ambient temperature and exhibits a quadratic relationship with tube spacing. There is no need to add a heat insulation layer at the bridge deck bottom, and only tubes arranged near the wheels in lanes are recommended.

Study on Finite Element Modeling Method of Cylinder Block

2011 ◽  
Vol 143-144 ◽  
pp. 546-550
Author(s):  
Min Li ◽  
Zeng Hui Yin ◽  
Jian Jun Yao ◽  
Jian Xin Liu ◽  
Hui Yong Du
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Element Model ◽  
Cylinder Block ◽  
Evaluation Indexes ◽  
Block Modeling ◽  
Modeling Methods ◽  
Processing Software ◽  
Complex Parts ◽  
The Finite Element Model

Based on finite element pre-processing software HyperMesh and SimLab, the finite element model of a four-cylinder diesel engine block was built, the characteristics of the two meshing tools were also be described. Using inhere free modal frequencies and shapes as evaluation indexes, the influences of cylinder block modeling methods were studied. By using HyperMesh combined with SimLab, an efficiency mesh generation method of cylinder block was proposed. This mesh generation method can also be used in the modeling of other complex parts.

Experimental and Numerical Study of Gas-Liquid Displacements in Flow Cells, With Application to Carbon Dioxide Sequestration in Brine Fields

2002 ◽  
Author(s):  
Duane Smith ◽  
Goodarz Ahmadi ◽  
Chuang Ji ◽  
Grant Bromhal ◽  
Martin V. Ferer
Keyword(s):  
Co2 Sequestration ◽  
Numerical Study ◽  
Carbon Dioxide Sequestration ◽  
Flow Cell ◽  
Immiscible Fluids ◽  
Flow Cells ◽  
Modeling Methods ◽  
Simulation Results ◽  
Fingering Phenomena ◽  
Good Agreement

In this paper experimental and computational modeling methods for studying viscous fingering phenomena occurring during underground CO2 sequestration were developed. In the experiment, the displacement of two immiscible fluids in a lattice-like flow cell was studied. The flow pattern during the displacement was analyzed, and the residual saturation of the displaced fluid was measured. Numerical simulations of the experimental flow cell were performed. The numerical simulation results are compared with the experimental data good agreement was observed.

Numerical Simulations of Turbulent Mixing and Autoignition of Hydrogen Fuel at Reheat Combustor Operating Conditions

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Elizaveta M. Ivanova ◽  
Berthold E. Noll ◽  
Peter Griebel ◽  
Manfred Aigner ◽  
Khawar Syed
Keyword(s):  
Natural Gas ◽  
Numerical Simulations ◽  
Flue Gas ◽  
Turbulent Mixing ◽  
Turbulence Modeling ◽  
Numerical Study ◽  
Operating Conditions ◽  
Fuel Blend ◽  
Flow Configuration ◽  
Modeling Methods

Turbulent mixing and autoignition of H2-rich fuels at relevant reheat combustor operating conditions are investigated in the present numerical study. The flow configuration under consideration is a fuel jet perpendicularly injected into a crossflow of hot flue gas (T>1000K,p=15 bar). Based on the results of the experimental study for the same flow configuration and operating conditions, two different fuel blends are chosen for the numerical simulations. The first fuel blend is a H2/natural gas/N2 mixture at which no autoignition events were observed in the experiments. The second fuel blend is a H2/N2 mixture at which autoignition in the mixing section occurred. First, the non-reacting flow simulations are performed for the H2/natural gas/N2 mixture in order to compare the accuracy of different turbulence modeling methods. Here, the steady-state Reynolds-averaged Navier- Stokes (RANS) as well as the unsteady scale-adaptive simulation (SAS) turbulence modeling methods are applied. The velocity fields obtained in both simulations are directly validated against experimental data. The SAS method shows better agreement with the experimental results. In the second part of the present work, the autoignition of the H2/N2 mixture is numerically studied using the 9-species 21-steps reaction mechanism of O’Conaire et al. (Int. J. Chem. Kinet., 36(11), 2004). As in the reference experiments, autoignition can be observed in the simulations. Influences of the turbulence modeling as well as of the hot flue gas temperature are investigated. The onset and the propagation of the ignition kernels are studied based on the SAS modeling results. The obtained numerical results are discussed and compared with data from experimental autoignition studies.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

Numerical study of the low-frequency atomic dynamics in a Lennard-Jones glass

1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,
Keyword(s):  
Numerical Study ◽  
Low Frequency ◽  
Lennard Jones
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