Turbulence modeling of natural convection in enclosures: A review

Choi, Seok-Ki; Kim, Seong-O

doi:10.1007/s12206-011-1037-0

Cited by 59 publications

(13 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Zhang et al (2007) evaluated various turbulence models in predicting airflow and turbulence flow in enclosed environments. Choi and Kim (2012) reviewed several recent developments of turbulence models for natural convection in enclosures. Gupta et al (2011) studied the transport of expiratory droplets in an aircraft cabin and found that the bulk airflow pattern in cabin played the most important role on the droplet transport.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the unsteady flow characteristics of human body thermal plume

et al. 2016

View full text Add to dashboard Cite

Human thermal plume is quite important to the study of airflow organization in the indoor environment, especially in the micro-environment research such as personalized ventilation, infectious disease transmission through air, etc. In order to investigate the unsteady fluctuation of the thermal plume around human body, a series of transient numerical simulations are conducted in this study. Numerical simulation based on 9.7 million grids and 0.02 s time step is performed to obtain the detail quantitative data of flow field. The obvious fluctuation and separation are captured in the upper flow region of human body based on the high resolution grids. The maximum time-averaged velocity of the thermal plume is found to be 0.25 m/s while the maximum fluctuate velocity is about 0.07 m/s. The further analysis of frequency spectrum shows that the thermal plume around the body is mainly dominated by the low frequency fluctuation which is lower than 1 Hz and the principal frequency is around 0.1 Hz. In order to overcome the drawback of the high computation cost for application of the engineering simulation, a new numerical simulation method combining a modified k-ε turbulence model and coarse grids is presented. This modified k-ε model can reduce the calculation error of Reynolds stress in the flow region of natural convection through redefining the turbulence viscosity coefficient segmentally and avoid a high numerical viscosity appeared due to the central difference scheme. It can reasonably predict the general fluctuation velocity and the frequency distribution during simulation process in coarse grids and show a huge potential to be applied to the engineering application.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the unsteady flow characteristics of human body thermal plume

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The point thermal transmittance TT3D (W/K) of the light guides was calculated. The TT3D is defined in standard ISO 10211 [29] for steady state heat transfer and for temperature difference between the environments on either side of a thermal bridge:…”

Section: Resultsmentioning

confidence: 99%

“…and indoor and outdoor temperatures are defined in accordance with standard values [29]. The 2D model of light guides was studied for thermal and air flow distribution under the defined boundary conditions.…”

Section: The Final 2d Simplified Modelmentioning

confidence: 99%

Thermal CFD Analysis of Tubular Light Guides

2013

View full text Add to dashboard Cite

Tubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulent air flow. The turbulent model was applied despite the small heat flux differences between the turbulent and laminar model. The CFD simulations resulted into conclusions that the growing ratio of length/diameter increases the heat transmission loss/linear transmittance as much as by 50 percent. Tubular light guides of smaller diameters have lower heat transmission losses compared to the wider ones of the same lengths with the same outdoor temperature being taken into account. The simulation results confirmed the thermal bridge effect of the tubular light guide tube inside the insulated flat roof details. The thermal transmittance of the studied light guides in the whole roof area was substituted with the point thermal bridges. This substitution gives possibility for simple thermal evaluation of the tubular light pipes in roof constructions.

show abstract

“…Literature review on performance of turbulence models Se observa que muchos autores han evaluado los modelos k-ω estándar y k-ω SST para NC, los que muestran un excelente desempeño para predecir la temperatura y la velocidad. Un par de estudios (Choi & Kim, 2012; también han mostrado un excelente desempeño del modelo v2f y su variable v2f-dav para NC.…”

Section: Evaluación De Los Modelos De Turbulenciaunclassified