Numerical investigation of thermal radiation effects on open cavity with discrete heat sources

Abstract

PurposeNatural convection heat transfer combined with radiation heat transfer is used in electronic cooling. The purpose of this paper is to investigate the thermal loading characteristics of an enclosure.Design/methodology/approachThe goal is to investigate the effect of thermal radiation on thermal and flow characteristics of the cavity. The enclosure lower wall is at constant temperature and the upper wall is adiabatic while there are several discrete heat sources inside the cavity. In addition the effect of parameters such as heating number (Nr), aspect ratio (A), the number of heaters (N), and thermal radiation on the maximum and mean temperature of system, thermal loading characteristics of the system, Nusselt number, and the maximum stream function rate is performed. To solve the governing nonlinear differential equations (mass, momentum, and energy), a finite‐volume code based on Patankar's SIMPLE method is utilized.FindingsHeat transfer by natural convection solely and it's conjugation with thermal radiation on the thermal and flow characteristics of the system is studied. Also a parametric study illustrating the influence of the heating number, aspect ratio, the number of heaters, and thermal radiation on the maximum and mean temperature of system, thermal loading characteristics of the system, Nusselt number, and the maximum stream function rate is investigated. The results have revealed that the thermal radiation have an important effect on the thermal characteristics of system at low heating numbers.Research limitations/implicationsThe relevant governing parameters were: the heating number, Nr from 0.05 to 500, the cavity aspect ratio, A=H/L from 0.1 to 1 and the number of heaters, N, is an odd number ranging from 1 to 19Practical implicationsThis work is numerical investigation only but can have engineering application such as electronic cooling, transformers, fusion reactors technology, hot structures, fuel cells, fibrous insulations and solar‐energy drying systems.Originality/valueThe effect of radiation in enclosure with discrete heaters within fluid has not been addressed in the literature.