Computational Study of Methane-air Combustion Using the Species Transport Model

2022 ◽  
Author(s):  
MD Amzad Hossain
Keyword(s):  
Transport Model ◽  
Computational Study ◽  
Species Transport

Numerical Simulation of Two-Phase Liquid–liquid Flow in a New Static Mixer Structure

2011 ◽  
Vol 368-373 ◽  
pp. 1604-1607
Author(s):  
Hong Yan Zhang ◽  
Hai Hong Dong
Keyword(s):  
Numerical Simulation ◽  
Liquid Flow ◽  
Transport Model ◽  
Simulation Method ◽  
Static Mixer ◽  
Mixing Process ◽  
Two Phase ◽  
Species Transport ◽  
Mixing Effect ◽  
Phase Liquid

In this article, Spiral belt static mixer with changing diameter was taken as the object. The numerical simulation method was used to investigate the mixing process of two-phase liquid–liquid flow in water treatment by a commercial CFD code,namely Fluent.The k-ε model and species transport model were established to research this project. Then the mixing effect was compared with that of HEV static mixer. The result showed that spiral belt static mixer with changing diameter promote the mixing effect greatly. The mixing effect relative to that of HEV static mixer increased 10 times and the the pressure loss only increased 3 times.

A Computational Study of Turbulent Airflow and Tracer Gas Diffusion in a Generic Aircraft Cabin Model

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Khosrow Ebrahimi ◽  
Zhongquan C. Zheng ◽  
Mohammad H. Hosni
Keyword(s):  
Transport Model ◽  
Computational Study ◽  
Flow Behavior ◽  
Gas Diffusion ◽  
Wall Function ◽  
Tracer Gas ◽  
Airflow Velocity ◽  
Aircraft Cabin ◽  
Cfd Models ◽  
Turbulent Airflow

In order to study the capability of computational methods in investigating the mechanisms associated with disease and contaminants transmission in aircraft cabins, the computational fluid dynamics (CFD) models are used for the simulation of turbulent airflow and tracer gas diffusion in a generic aircraft cabin mockup. The CFD models are validated through the comparisons of the CFD predictions with corresponding experimental measurements. It is found that using large eddy simulation (LES) with the Werner-Wengle wall function, one can predict unsteady airflow velocity field with relatively high accuracy. However in the middle region of the cabin mockup, where the recirculation of airflow takes place, the accuracy is not as good as that in other locations. By examining different k-ε models, the current study recommends the use of the RNG k-ε model with the nonequilibrium wall function as an Reynolds averaged Navier-Stokes model for predicting the steady-state airflow velocity. It is also found that changing the nozzle height has a significant effect on the flow behavior in the middle and upper part of the cabin, while the flow pattern in the lower part is not affected as much. Through the use of LES and species transport model in simulating tracer gas diffusion, a very good agreement between predicted and measured tracer gas concentration is achieved for some monitoring locations, but the agreement level is not uniform for all the locations. The reasons for the deviations between prediction and measurement for those locations are discussed.

scholarly journals High mixing performances of shear-thinning fluids in two-layer crossing channels micromixer at very low Reynolds numbers

2019 ◽  
Vol 13 (4) ◽  
pp. 5938-5960
Author(s):  
A. Kouadri ◽  
Y. Lasbet ◽  
M. Makhlouf
Keyword(s):  
Reynolds Number ◽  
Power Law ◽  
Transport Model ◽  
Tangential Velocity ◽  
Reynolds Numbers ◽  
Mixing Efficiency ◽  
Species Transport ◽  
Industrial Sectors ◽  
Power Law Fluids ◽  
Power Law Index

In a recent study, the Two-Layer Crossing Channels Micromixer (TLCCM) exhibited good mixing capacities in the case of the Newtonian fluids (close to 100%) for all considered Reynolds number values. However, since the majority of the used fluids in the industrial sectors are non-Newtonians, this work details the mixing evolution of power-law fluids in the considered geometry. In this paper, the power-law index ranges from 0.73 to 1 and the generalized Reynolds number is bounded between 0.1 and 50. The conservation equations of momentum, mass and species transport are numerically solved using a CFD code, considering the species transport model. The flow structure at the cross-sectional planes of our micromixer was studied using the dynamic systems theory. The evolutions of the intensity, also the axial, radial and tangential velocity profiles were examined for different values of the Reynolds number and the power-law index. Besides, the pressure drop of the power-law fluids under different Reynolds number was calculated and represented. Furthermore, the mixing efficiency is evaluated by the computation of the mixing index (MI), based on the standard deviation of the mass fraction in different cross-sections. In such geometry, a perfect mixing is achieved with MI closed to 99.47 %, at very small Reynolds number (from the value 0.1) whatever the power-law index and generalized Reynolds numbers taken in this investigation. Consequently, the targeted channel presents a useful tool for pertinent mass transfer improvements, it is highly recommended to include it in various microfluidic systems.

Drag Characterization Study of Variable Camber Continuous Trailing Edge Flap

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Upender K. Kaul ◽  
Nhan T. Nguyen
Keyword(s):  
Transport Model ◽  
Computational Study ◽  
Lift Coefficient ◽  
Navier Stokes ◽  
Trailing Edge ◽  
Characterization Study ◽  
Analysis Of Results ◽  
Trailing Edge Flap ◽  
Lift And Drag ◽  
Flap Region

A Reynolds-averaged Navier–Stokes (RANS) computational study was conducted to investigate the effect of various variable camber continuous trailing edge flap (VCCTEF) configurations on the lift and drag of a NASA generic transport model (GTM) wing section. Out of the five two-dimensional (2D) VCCTEF configurations considered with varying camber in the three-segment flap region, with a total deflection of 6 deg, the best stall performance was exhibited by the circular and parabolic arc camber flaps. Both circular and parabolic arc flaps give similar lift performance, with the circular arc yielding a higher lift coefficient and parabolic arc resulting in the lowest drag and hence the best L/D performance at design Cl. Analysis of results based on linear theory shows excellent agreement between computed and theoretical incremental lift.

Hydrogenic species transport model for ceramic alumina used in ITER ICRH H&CD & Diagnostics Systems

2007 ◽  
Vol 82 (15-24) ◽  
pp. 2647-2654 ◽  
Author(s):  
C. Moreno ◽  
L.A. Sedano ◽  
K.J. McCarthy ◽  
E.R. Hodgson
Keyword(s):  
Transport Model ◽  
Species Transport

Numerical Modeling and Simulation of Condensation Heat Transfer in a Bundle of Transport Membrane Tubes for Waste Heat and Water Recovery

2011 ◽  
Author(s):  
Cheng-Xian Charlie Lin ◽  
Dexin Wang ◽  
Ainan Bao
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Flue Gas ◽  
Transport Model ◽  
Waste Heat ◽  
Numerical Study ◽  
Tube Bundle ◽  
Inlet Temperature ◽  
Water Recovery ◽  
Species Transport

In this paper, a numerical study has been carried out to investigate the heat and mass transfer with condensation in a transport membrane tube bundle, which is used for recovering both heat and water from combustion flue gas. The tube wall is made of a specially designed porous material that is able to extract condensate liquid from the flue gas. The flue gas investigated consists of one condensable water vapor (H2O) and three noncondensable gases (CO2, O2, and N2). A simplified multi-species transport model was developed for the heat and mass transfer of flue gas. The condensation-evaporation process was simulated as a two-step chemical reaction. The RNG two-equation turbulence model was used for the turbulent flow. The numerical study was conducted within ranges of Reynolds number of 1.0×103–7×104 based on hydraulic diameter of flue gas channel, and 6.4×100–3.3×102 based on inner diameter of the water tube. Flue gas inlet temperature is within the range of 333.2–360.9 K, while the water inlet temperature is within the range of 293.9–316.7 K. Numerical results were compared with experimental data obtained in a parallel effort. It has been found that the developed multi-species transport model was able to predict the flue gas heat and mass transfer in the tube bundle with fairly good accuracy. The heat and mass depletion levels decrease with the increase of the flue gas Reynolds numbers. A new Nusselt number correlation was developed for flue gas convection in the tube bundle. Detailed results about temperature, mass fraction, enthalpy, and skin fraction factors are also presented and discussed.

Evaluation of Turbulence Models for Thermal Striping in a Triple-Jet

2005 ◽  
Author(s):  
Seok-Ki Choi ◽  
Ho-Yun Nam ◽  
Myung-Hwan Wi ◽  
Seong-O Kim ◽  
Jong-Chull Jo ◽  
...  
Keyword(s):  
Experimental Data ◽  
Root Mean Square ◽  
Transport Model ◽  
Computational Study ◽  
Turbulence Models ◽  
Oscillatory Behavior ◽  
Mean Square ◽  
Relaxation Model ◽  
Elliptic Relaxation ◽  
Thermal Striping

A computational study for the evaluation of the current turbulence models for the prediction of a thermal striping in a triple-jet is performed. The tested turbulence models are the two-layer model, the shear stress transport model and the elliptic relaxation model. These three turbulence models are applied to the prediction of the thermal striping in a triple-jet in which detailed experimental data are available. The performances of the tested turbulence models are evaluated through comparisons with the experimental data. The predicted mean and root-mean-square values of the temperature are compared with the experimental data, and the capability of predicting the oscillatory behavior of the ensemble-averaged temperature is investigated. From these works it is shown that only the elliptic relaxation model is capable of predicting the oscillatory behavior of the ensemble-averaged temperature. It is also shown that the elliptic relaxation model predicts best the time-averaged and root-mean-square of the temperature fluctuation. However, this model predicts a slower mixing at the far downstream of the jet.

A Continuum Model of Thrombus Growth and Flow Impingement

2002 ◽  
Author(s):  
David M. Wootton
Keyword(s):  
Platelet Activation ◽  
Continuum Model ◽  
Transport Model ◽  
Species Transport ◽  
Activation Kinetics ◽  
Platelet Size

A species transport model of thrombosis is developed, which includes effects of thrombus impingement on the flow and finite platelet size. The model is implemented in commercial CFD package for easy transfer. Preliminary calculations, neglecting platelet activation kinetics, are consistent with experiments, and model the deflection of flow around the growing thrombus.

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