In this paper the authors numerically investigate dynamic heat transfer related to free convection in porous and partially porous cavities, paying particular attention to the dependence of velocity and temperature fields on Rayleigh (Ra) number, porous layer permeability, and cavity aspect ratio (AR), that is the ratio between its height and width. Heat and fluid flow inside the cavity have been described by using the generalized porous medium model and the governing equations have been numerically solved using the Artificial Compressibility (AC) version of the Characteristic Based Split (CBS) scheme. The proposed model has been firstly applied to the simulation of heat and fluid flow in a square porous cavity, and an excellent agreement has been found between the obtained results and the data available in the literature. Then, the analysis has been extended, here for the first time, to the transient natural convection in partly porous cavities with AR equal to 4:1 and 8:1, for different Ra and Darcy (Da) numbers. The mean Nusselt (Nu) number has been calculated as function of cavity geometrical characteristics, porous layer permeability and fluid properties.
TRANSIENT INCOMPRESSIBLE FLOW IN A PARTIALLY POROUS BUOYANCY DRIVEN TALL CAVITY
ARPINO, Fausto;CORTELLESSA, Gino;DELL'ISOLA, Marco;FICCO, Giorgio;
2015-01-01
Abstract
In this paper the authors numerically investigate dynamic heat transfer related to free convection in porous and partially porous cavities, paying particular attention to the dependence of velocity and temperature fields on Rayleigh (Ra) number, porous layer permeability, and cavity aspect ratio (AR), that is the ratio between its height and width. Heat and fluid flow inside the cavity have been described by using the generalized porous medium model and the governing equations have been numerically solved using the Artificial Compressibility (AC) version of the Characteristic Based Split (CBS) scheme. The proposed model has been firstly applied to the simulation of heat and fluid flow in a square porous cavity, and an excellent agreement has been found between the obtained results and the data available in the literature. Then, the analysis has been extended, here for the first time, to the transient natural convection in partly porous cavities with AR equal to 4:1 and 8:1, for different Ra and Darcy (Da) numbers. The mean Nusselt (Nu) number has been calculated as function of cavity geometrical characteristics, porous layer permeability and fluid properties.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
