Interaction between the mixing and displacement modes in a naturally ventilated enclosure

Navarro

et al. 2017

In this study, experimental and numerical results of heat transfer in a ventilated cavity with an internal heat source are presented. The cavity represents a ventilated room with a person inside in a 1:3 scale. It has a vertical wall receiving a constant and uniform heat flux, while the opposite wall is kept at a constant temperature. The rest of the walls is adiabatic. The cavity has multiple inlets and outlets of air, considering ventilation by ducts of an airconditioning system. Experimental temperature profiles were obtained at six different depths and heights consisting of 14 thermocouples each. Six turbulence models were evaluated against experimental data. The minimum average percentage differences between numerical and experimental average Nusselt numbers of the hot wall and heat source were 12.9% and 4.1% with the renormalized k-e turbulence model.

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of turbulent mixed convection in a cavity with an internal heat source

Piña-Ortiz

Navarro

et al. 2017

“…Near the hot wall, the fluid flow is always enclosed to the wall and has an ascendant direction that influences the air movement. Haslavsky et al (2006) carried out the experiments to study the interactive phenomena in buoyancy-induced natural ventilation, in a full-scale enclosure with upper and lower openings on one of the sidewalls. Both the transient process and steady-state interaction are explored.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer and airflow study of turbulent mixed convection in a ventilated cavity

Rodríguez

Xamán

2016

The experimental and numerical results of the heat transfer and airflow by turbulent mixed convection in a ventilated cavity are presented. The experimental setup was built to use air as the heat transfer fluid. One vertical wall receives a uniform and constant heat flux, whereas the opposite wall is maintained at constant temperature. The remaining walls are thermally insulated. The experimental temperature profiles were obtained for different heat fluxes and air inlet velocities. Five different turbulence models were used to obtain the numerical results. The comparison between experimental and numerical temperatures indicates that the standard k–ε turbulence model presents a better agreement, with maximum percentage differences between 2.0% and 3.0%. The heat transfer coefficient had values between 2.2 and 3.4 W/m2 K, and it increases with the Rayleigh number and the Reynolds number. The experimental and numerical convective heat transfer coefficient predictions are closer for the higher Reynolds number (inlet air velocity of 0.5 m/s). The effects of varying the Rayleigh and Reynolds number on flow patterns and temperature fields were analyzed numerically.

“…The comparison between 3D and 2D simulations showed that a 3D model is needed to capture the fluid mechanics for Ri = 10 when 10 < Re < 250 and to calculate the global Nusselt number when Re = 500 for Ri \ 1. Haslavsky et al (2006) carried out the experiments of the interactive phenomena in buoyancy-induced natural ventilation, in a full-scale enclosure with upper and lower openings on one of the sidewalls. Both the transient process and steady-state interaction are explored.…”

Section: Introductionmentioning

confidence: 99%

“…Haslavsky et al (2006) carried out the experiments of the interactive phenomena in buoyancy-induced natural ventilation, in a full-scale enclosure with upper and lower openings on one of the sidewalls. Both the transient process and steady-state interaction are explored.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of airflow and heat transfer in an air-cooled room with different inlet positions

Rodríguez

2012

This study is focused to airflow and heat transfer analyses in an air-cooled room. Three-dimensional numerical results of a rectangular room considering three different inlet configurations are presented. The study was carried out considering turbulent flow and the radiative exchange between the walls. A vertical wall receives a constant heat flux, and the opposite wall is maintained at a uniform and constant temperature; the remaining walls are adiabatic. The air inlet velocity was 0.5 m/s and the emissivity of the walls was considered as 0.8. The mathematical model was solved numerically with Computational Fluid Dynamics software. The temperature fields, flow patterns, heat transfer coefficients, and temperature distribution effectiveness are presented and discussed. It was found that the heat transfer due to the radiative effect is around 50% for the three cases studied; besides, the heat transfer coefficients and temperature distribution effectiveness are highly dependent on the inlet position.