American Journal of Engineering and Applied Sciences

Combined Thermal Radiation and Mixed Convection in an Inclined Circular Duct

W. Lakhal, S. Trabelsi, E. Sediki and M. Moussa

DOI : 10.3844/ajeassp.2009.590.602

American Journal of Engineering and Applied Sciences

Volume 2, Issue 4

Pages 590-602

Abstract

Problem statement: Modeling thermal radiation with simultaneous buoyancy and forced convection for real gases flowing inside system with complex geometry is a difficult task encountered in engineering applications. Purpose of this study was to research numerically the interaction of mixed convection and thermal radiation in laminar air flow inside an inclined cylindrical duct with Uniform Wall Heat Flux (UWHF). This study highlighted the radiative double effects of water vapor in air flow on thermal and on dynamic fields. Approach: Flow equations and energy balance equation were solved simultaneously with temperature dependant thermophysical properties. An implicit finite difference technique was used to solve mass, momentum and energy equations. In order to take into account the non-gray radiative behavior of water vapor (H2O), a global absorption distribution function model was used to represent the infrared radiative properties. Results: Results were presented in term of temperature, velocity and radiative power fields and of evolution of bulk temperature and Nusselt numbers. Effects of thermal radiation on temperature and on velocity distributions were also examined. Conclusion/Recommendations: It was shown that inclination angle of duct had a significant effect on thermal and dynamic fields especially for thick medium. Radiation strongly affected the velocity profiles. Numerical results were discussed referring to available experimental data in order to improve estimations of engineering parameters.

Copyright

© 2009 W. Lakhal, S. Trabelsi, E. Sediki and M. Moussa. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.