Numerical investigation of combined convection and radiation heat transfer in the horizontal ducts heated from different orientations

Abstract

The heating or cooling process in a duct is employed by one or more heat transfer modes. The study aims to study the heat transfer physiognomies of combined convection and radiation in horizontal ducts heated from various orientations numerically. The square test section includes two isothermal vertical walls and two adiabatic horizontal walls. Two isothermals high and low temperature walls, respectively, act as a heat source and constant temperature sink. Surface radiation has been shown to alter overall heat transmission within the duct. The computation of Nusselt numbers shows that even at low temperatures (100°C), surface radiation effects are significant. Visible flow patterns within the square test section were observed concerning different heating configurations. The results showed that the temperature distribution along the duct walls and the flow conditions significantly affected the total Nusselt number. Moreover, major parameters such as Reynolds number, internal wall surface emissivity, and heating configurations have a significant impact on the total Nusselt number.