A New Numerical Procedure for Coupling Radiation in Participating Media With Other Modes of Heat Transfer

2005 ◽  
Vol 127 (9) ◽  
pp. 1037-1045 ◽  
Author(s):  
Sandip Mazumder
Keyword(s):  
Heat Transfer ◽  
Energy Equation ◽  
Numerical Procedure ◽  
Computer Code ◽  
Point Of View ◽  
Stability And Convergence ◽  
Participating Media ◽  
Solution Approach ◽  
Coupling Approach ◽  
Coupled Solution

Traditionally, radiation in participating media is coupled to other modes of heat transfer using an iterative procedure in which the overall energy equation (EE) and the radiative transfer equation (RTE) are solved sequentially and repeatedly until both equations converge. Although this explicit coupling approach is convenient from the point of view of computer code development, it is not necessarily the best approach for stability and convergence. A new numerical procedure is presented in which the EE and RTE are implicitly coupled and solved simultaneously, rather than as segregated equations. Depending on the average optical thickness of the medium, it is found that the coupled solution approach results in convergence that is between 2–100 times faster than the segregated solution approach. Several examples in one- and two-dimensional media, both gray and nongray, are presented to corroborate this claim.

Coupling Radiation in Participating Media With Other Modes of Heat Transfer: Segregated Versus Coupled Solution

2005 ◽  
Author(s):  
Sandip Mazumder
Keyword(s):  
Heat Transfer ◽  
Energy Equation ◽  
Numerical Procedure ◽  
Computer Code ◽  
Point Of View ◽  
Stability And Convergence ◽  
Participating Media ◽  
Solution Approach ◽  
Coupling Approach ◽  
Coupled Solution

Traditionally, radiation in participating media is coupled to other modes of heat transfer using an iterative procedure in which the overall energy equation (EE) and the radiative transfer equation (RTE) are solved sequentially and repeatedly until both equations converge. While this explicit coupling approach is convenient from the point of view of computer code development, it is not necessarily the best approach for stability and convergence. A new numerical procedure is presented in which the EE and the RTE are implicitly coupled and solved simultaneously, rather than as segregated equations. Depending on the average optical thickness of the medium, it is found that the coupled solution approach results in convergence that is between two to one hundred times faster than the segregated solution approach. Several examples in one and two-dimensional media, both gray and nongray, are presented to corroborate this claim.

scholarly journals Numerical Predictions of Local Entropy Generation in an Impinging Jet

1991 ◽  
Vol 113 (4) ◽  
pp. 823-829 ◽  
Author(s):  
M. K. Drost ◽  
M. D. White
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Numerical Procedure ◽  
Computer Code ◽  
Velocity Fields ◽  
Heated Wall ◽  
Local Entropy ◽  
Numerical Predictions ◽  
Temperature And Velocity Fields ◽  
Local Entropy Generation

Local entropy generation rates related to viscous dissipation and heat transfer across finite temperature differences can be calculated for isotropic and Newtonian fluids from the temperature and velocity fields in a thermal process. This study consisted of the development of a numerical procedure for the prediction of local entropy generation rates and the application of that procedure to convective heat transfer associated with a fluid jet impinging on a heated wall. The procedure involved expanding an existing computation fluid dynamics computer code to include the numerical calculation of local entropy generation. The modified code was bench-marked against analytical solutions and was then used to simulate a cold fluid jet impinging on a hot wall. The results show that the calculation of local entropy generation is feasible and can provide useful information.

Modeling of Newtonian and non-Newtonian-based coolants for deployment in industrial length-scale shell and tube heat exchanger

2021 ◽  
pp. 2150085
Author(s):  
S. Anitha ◽  
Tiju Thomas ◽  
V. Parthiban ◽  
M. Pichumani
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Volume Fraction ◽  
Numerical Procedure ◽  
Point Of View ◽  
Hybrid Nanofluid ◽  
Tube Heat Exchanger ◽  
Shell And Tube ◽  
Hybrid Nanofluids

To evaluate the heat transfer performance (HTP) of hybrid nanofluids, numerical simulations are carried out in an industrial length single pass shell and tube heat exchanger. In shell, ISO VG 68 oil enters with [Formula: see text]C and with [Formula: see text]C, the coolant passes into the tube. CNT-[Formula: see text]/water and CNT-[Formula: see text]/sodium alginate (SA) are used as Newtonian and non-Newtonian hybrid nanofluid, respectively. The influence of base fluid and nanoparticles on thermal performance of heat exchanger is studied. The chosen nanoparticles are reliable to the industrial deployment. The current numerical procedure is validated with the earlier experimental results. Volume fraction of nanoparticles is optimized for an effective HTP of the heat exchanger. About 60% increment in heat transfer coefficient is observed when hybrid nanofluid is employed. By using Newtonian hybrid nanofluid, 50% improvement in Nusselt number is marked out. Effectiveness and heat transfer rate of heat exchanger are higher with the employment of Newtonian hybrid nanofluid. Results indicated that, even though Newtonian hybrid nanofluid shows higher thermal performance, non-Newtonian hybrid nanofluid is preferable for energy consumption point of view.

Numerical investigation of heat transfer by natural convection and radiation in a cavity with participating media

2016 ◽  
Author(s):  
CRISTIAN URIEL MENDOZA CASTELLANOS ◽  
Jan Armengol ◽  
Carlos Salinas ◽  
Rafael Beicker Barbosa ◽  
Rogério Gonçalves dos Santos
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Investigation ◽  
Participating Media
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