Numerical analysis of heat and fluid flow characteristics of airflow inside rectangular channel with presence of perforated concave delta winglet vortex generators

Abstract

This study is intended to analyze numerically and experimentally the characteristics of heat transfer augmentation and pressure drop of airflow through vortex generators mounted to a heated plate inside a rectangular channel. Delta winglet pairs (DWPs) and concave delta winglet pairs (CDWPs) vortex generators (VGs) with one, two, and three rows were used in this study. Heat transfer enhancement and pressure drop of flow passing through the VGs with a 5 mm diameter hole for one, two, and three holes in certain positions were investigated. VGs were mounted in-line with an attack angle of 15° to the flow. The airflow was assumed to be incompressible; the steady-state and air velocity were varied in the range of 0.4 m/s to 2 m/s. The analysis showed that the use of holes in the delta winglet vortex generators could reduce the pressure drop of 34.14% from the delta winglet without holes at a velocity of 2 m/s. By using perforated delta (DWP VGs) and concave delta winglet (CDWP VGs), the heat transfer coefficient is reduced by 1.81% and 7.03% of the delta and concave delta winglet vortex generators without holes at a velocity of 2 m/s.