The present work details a numerical simulation of forced convective laminar flow in a channel with a heated obstacle attached to one wall. The second law analysis is employed to investigate the distribution of entrop...The present work details a numerical simulation of forced convective laminar flow in a channel with a heated obstacle attached to one wall. The second law analysis is employed to investigate the distribution of entropy generation in the flow domain to demonstrate the rate of irreversibilities in thermal system. The conjugate problem including the convection heat transfer in the fluid flow and conduction one inside the obstacle is solved numerically to obtain the velocity and temperature fields in both gas and solid phases. To reach this goal, the set of governing equations including momentum and energy equations for the gas phase and conduction equation for the obstacle are solved by CFD technique to determine the hydrodynamic and thermal behaviors of the fluid flow around the obstacle and the temperature distribution in the solid element. An attempt is made to detail the local Nusselt number distribution and mean Nusselt number and also the local entropy generation distribution for the individual exposed obstacle faces. A good consistency is found between the present numerical results with experiment.展开更多
In the current study, a numerical investigation of three-dimensional combined convection-radiation heat transfer over an inclined forward facing step (FFS) in a horizontal rectangular duct is presented. The fluid is t...In the current study, a numerical investigation of three-dimensional combined convection-radiation heat transfer over an inclined forward facing step (FFS) in a horizontal rectangular duct is presented. The fluid is treated as a gray, absorbing, emitting and scattering medium. To simulate the incline surface of FFS, the blocked-off method is employed in this study. The set of governing equations for gas flow are solved numerically using the CFD technique to obtain the temperature and velocity fields. Since the gas is considered as a radiating medium, all of the convection, conduction and radiation heat transfer mechanisms are presented in the energy equation. For computation of radiative term in energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinates method (DOM) to find the divergence of radiative heat flux distribution inside the radiating medium. The effects of optical thickness, radiation-conduction parameter and albedo coefficient on heat transfer behavior of the system are carried out.展开更多
文摘The present work details a numerical simulation of forced convective laminar flow in a channel with a heated obstacle attached to one wall. The second law analysis is employed to investigate the distribution of entropy generation in the flow domain to demonstrate the rate of irreversibilities in thermal system. The conjugate problem including the convection heat transfer in the fluid flow and conduction one inside the obstacle is solved numerically to obtain the velocity and temperature fields in both gas and solid phases. To reach this goal, the set of governing equations including momentum and energy equations for the gas phase and conduction equation for the obstacle are solved by CFD technique to determine the hydrodynamic and thermal behaviors of the fluid flow around the obstacle and the temperature distribution in the solid element. An attempt is made to detail the local Nusselt number distribution and mean Nusselt number and also the local entropy generation distribution for the individual exposed obstacle faces. A good consistency is found between the present numerical results with experiment.
文摘In the current study, a numerical investigation of three-dimensional combined convection-radiation heat transfer over an inclined forward facing step (FFS) in a horizontal rectangular duct is presented. The fluid is treated as a gray, absorbing, emitting and scattering medium. To simulate the incline surface of FFS, the blocked-off method is employed in this study. The set of governing equations for gas flow are solved numerically using the CFD technique to obtain the temperature and velocity fields. Since the gas is considered as a radiating medium, all of the convection, conduction and radiation heat transfer mechanisms are presented in the energy equation. For computation of radiative term in energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinates method (DOM) to find the divergence of radiative heat flux distribution inside the radiating medium. The effects of optical thickness, radiation-conduction parameter and albedo coefficient on heat transfer behavior of the system are carried out.