Test of turbulence models for heat transfer within a ventilated cavity with and without an internal heat source

Piña-Ortiz, A.; Hinojosa, J.; Xamán, J.; Navarro, Jorge

doi:10.1016/j.icheatmasstransfer.2018.03.021

Cited by 12 publications

(9 citation statements)

References 24 publications

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“…The results show that for the studied case, the curves of turbulent kinetic energy and velocity along the cavity have almost the same variation for all the turbulent models with small difference between each model, where the rate of change between k-ε and other models does not exceed 3 %. However, since the computational time of k-ε model is much less than that of other models which is pointed out in the study of Piña-Ortiz et al (2018). Also, the k-ε model is selected for the further analysis.…”

Section: Governing Equationsmentioning

confidence: 99%

3D Numerical Simulation of Turbulent Mixed Convection in a Cubical Cavity Containing a Hot Block

Bouras¹,

Bouabdallah²,

Ghernaout³

et al. 2021

JAFM

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The considerable quantities of heat transfer are dissipated during the operating electronic/electrical systems and have harmful effects on the operating time. So; to keep these systems in good working condition, the location of efficient mechanical cooling systems is essential. The heat transfer rate in an enclosure intensely depends on the combination of geometrical and physical parameters. For this purpose, a 3D Numerical simulation of turbulent mixed convection in a cubical cavity containing an internal heat source in its middle was carried out. The cavity has an inlet port at the lower left face area and an outlet port located in the upper right face area. The analyses are performed for air at ambient circumstances (Pr = 0.71) and the variation of interval for Richardson number (Ri) is chosen between 0.01 and 30 to investigate three situations: dominated forced convection, natural convection, and mixed convection for a fixed dimension of the enclosure in turbulent regimes (Gr = 10 9 ). The effects of the variation of Ri, the dimensionless time, and the dynamic parameters on the thermal flow and fluid flow phenomena are presented and discussed. The obtained results show an exchange between the forces of pressure and of buoyancy in the studied interval and a strong dependence between the geometrical parameters and the heat transfer rate, and then the correlations of the combination of the parameters were proposed.

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Section: Governing Equationsmentioning

confidence: 99%

3D Numerical Simulation of Turbulent Mixed Convection in a Cubical Cavity Containing a Hot Block

Bouras¹,

Bouabdallah²,

Ghernaout³

et al. 2021

JAFM

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“…It can be seen from A realizable k-ε turbulent model will be used since it is known to have a good performance with indoor airflows, temperature and pressure in closed structures. [41][42][43][44][45] In the turbulence model, the enhanced wall treatment with pressure gradient effects and thermal effects, and the full buoyancy effect under gravity have been taken into account, but the viscous heating is ignored since the air flows in the living room at a low speed and there is almost no mechanical energy be converted into heat.…”

Section: Computational Model and Meshmentioning

confidence: 99%

Thermal performance of a mine refuge chamber with human body heat sources under ventilation

Zhang

Wang

et al. 2019

Applied Thermal Engineering

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This paper investigated the dynamic coupling heat transfer characteristics of rock and air in a Mine Refuge Chamber (MRC) under ventilation. In the current work, a comprehensive fiftyperson MRC model combining human-body heat sources and ventilation is established, the proposed model is validated against available experimental data with deviation less than 4%. Furthermore, sensitivity analysis is performed to investigate the influence of several control parameters such as heating rate, ventilation and wall area in a MRC through using numerical simulation. Results indicated that: (ⅰ) the heat transfer process in a MRC will reach a stage of air temperature slow increase (ATSI) in less than 0.5 h. The air temperature rises linearly with the square root of time during the ATSI stage; (ⅱ) for a MRC built in a sandstone seam with an initial rock temperature of less than 27 °C, the average air temperature will not exceed 35 °C in 96 h when the ventilation volume rate is 0.3 m 3 /min per person; (ⅲ) the rate of temperature rise in MRC is proportional to the rate of heat generation, but it is inversely proportional to the thermal conductivity, density and thermal capacity of the rock, as well as the ventilation volume rate and the wall area; (ⅳ) an empirical correlation for the MRC average air temperature is developed while the supply air temperature equals to the initial rock temperature. Keywords：Underground; Mine refuge chamber; Air temperature prediction; Ventilation; Heat transfer coefficient; Human body heat sources. Nomenclature a Constant in K expression V Ventilation volume for MRC, m 3 /h A w Wall area of MRC, m 2 x, y Coordinate direction vector b Constant in K expression Subscripts B Temperature variable, °C a Air c Constant in K expression num Numerical data C a Specific heat capacity of air, J/(kg• K) exp Experimental data C p Specific heat capacity of rock, J/(kg• K) Greek symbols d Constant in K expression α Surface heat transfer coefficient, W/(m 2 • K) i, j Constant in B expression Θ Difference k Constant in B expression ρ Density of rock, kg/m 3 K Rate for air temperature increasing, °C/s 0.5 ρ a Density of air, kg/m 3 l Constant in B expression λ Thermal conductivity of rock, W/(m• K) L Temperature variable, °C τ Heat time, h L c Perimeter of cross-section tunnel, m Acronyms m, n Constant in K expression ATSI Air temperature slow increase p Pressure, Pa CE Critical equilibrium Q Total heat generation rate in MRC, W MRC Mine refuge chamber r 0 equivalent radius of cross-section tunnel, m MMRC Movable mine rescue capsules T Temperature, °C PCM Phase change materials T 0 Initial rock temperature, °C

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“…Through a study of the natural convection phenomena inside a wall solar chimney, Bacharoudis et al [39] proved that the realizable k−ε model was likely to provide superior performance for flows boundary layers under strong adverse pressure gradients. Piña-Ortiz et al [40,41] proved that the Realizable k−ε model was the best model for natural convection in a cubic cavity with the lowest temperature difference. Therefore, the Realizable k−ε model is selected for the current study.…”

Section: Turbulence Modelmentioning

confidence: 99%

Thermal performance analysis of an underground closed chamber with human body heat sources under natural convection

Zhang

Day

Wang

et al. 2018

Applied Thermal Engineering

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Test of turbulence models for heat transfer within a ventilated cavity with and without an internal heat source

Cited by 12 publications

References 24 publications

3D Numerical Simulation of Turbulent Mixed Convection in a Cubical Cavity Containing a Hot Block

3D Numerical Simulation of Turbulent Mixed Convection in a Cubical Cavity Containing a Hot Block

Thermal performance of a mine refuge chamber with human body heat sources under ventilation

Thermal performance analysis of an underground closed chamber with human body heat sources under natural convection

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