Heat and mass transfer by natural convection in a square cavity filled with a mixture of Air–CO2

2013 ◽  
Vol 64 ◽  
pp. 725-734 ◽  
Author(s):  
J. Serrano-Arellano ◽  
J. Xamán ◽  
G. Álvarez ◽  
M. Gijón-Rivera
Keyword(s):  
Mass Transfer ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Square Cavity

Numerical Study of Heat and Mass Transfer by Laminar and Turbulent Natural Convection With Cross Diffusion Effects in Square Cavity

2008 ◽  
Author(s):  
Wenguang Geng ◽  
Baoming Chen ◽  
Maocheng Tian ◽  
Fang Liu
Keyword(s):  
Mass Transfer ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Soret Effect ◽  
Solute Concentration ◽  
Square Cavity ◽  
Component System ◽  
Turbulent Natural Convection ◽  
Cross Diffusion ◽  
Diffusion Effects

Laminar and turbulent natural convection flow in a two-dimensional square cavity filled two component system with compensating horizontal thermal and solute concentration gradients is investigated in this paper. The temperature gradient and volatile organic compounds (VOCs) concentration gradient are kept uniform in horizontal direction, while horizontal surfaces are kept adiabatic and impermeable within a square cavity. According to the principle of irreversible thermodynamics, with thermal-diffusion (Soret) effect and diffusion-thermo (Dufour) effect, a commercial computational fluid dynamics (Fluent) code is used to simulate heat and mass transfer numerically in present work. After validation of the method with available measurements, the range of the cross diffusion coefficients are analyzed firstly. Furthermore, the thermal field and solute concentration fields are presented for various conditions. Finally, the average Nusselt number and Sherwood number at the vertical wall are presented graphically. The numerical results show that the present work would help to know about the convective diffusion and distribution of VOCs indoor environment accurately. Also, it gives the more accurate characteristics of heat and mass transfer in multi-component system with cross diffusion effects.

The Experimental Investigation of Steam Condensation With Non-Condensable Gas Under Natural Convection

2018 ◽  
Author(s):  
Xizhen Ma ◽  
Wen Fu ◽  
Haijun Jia ◽  
Peiyue Li ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
High Pressure ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Vertical Wall ◽  
Experimental System ◽  
Steam Condensation ◽  
Transfer Coefficients ◽  
Calculation Results

The non-condensable gas is used to keep the pressure stable in the steam-gas pressurizer. The processes of heat and mass transfer during steam condensation in the presence of non-condensable gas play an important role and the thermal hydraulic characteristics in the pressurizer is particularly complicated due to the non-condensable gas. The effects of non-condensable gas on the process of heat and mass transfer during steam condensation were experimental investigated. A steam condensation experimental system under high pressure and natural convection was built and nitrogen was chosen in the experiments. The steam and nitrogen were considered in thermal equilibrium and shared the same temperature in the vessel under natural convection. In the experiments, the factors, for instance, pressure, mass fraction of nitrogen, subcooling of wall and the distribution of nitrogen in the steam, had been taken into account. The rate of heat transfer of steam condensation on the vertical wall with nitrogen was obtained and the heat transfer coefficients were also calculated. The characteristics curve of heat and mass transfer during steam condensation with non-condensable gas under high pressure were obtained and an empirical correlation was introduced to calculated to heat transfer coefficient of steam condensation with nitrogen which the calculation results showed great agreement with the experimental data.

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