Indian Journal of Science and Technology

Abstract

The paper brings Numerical study of thermal performance of solar air heater channel in which delta winglet type vortex generators with and without holes punched on it are attached. Delta winglet type vortex generators having holes punched onto it are fitted in an array having 5 pair in one row, having 3 such rows starting at the entry of test section. With pitch of 60mm.Deltawinglet pair have an attack angle of 30 degrees, with height of winglet equal to half of duct height The study is carried out for Reynolds’s No in the range of 5000 to 25000 by changing airflow rate.in the test section with its upper channel wall provided with a uniform heat flux. Results are then compared with that of duct mounted with delta winglet without holes. Thermal performance is evaluated by analyzing both friction factor and Nussult’s number using R L Webb’s correlation for surfaces with roughness. Numerical simulation is done using Ansys fluent software. Analysis findings says that use of winglets brings enhancement in the heat transfer and thus increases the thermal performance. Arrangement of winglets also influences the performance. Improvements in design and performance can be brought by using winglets with different attack angles and span length.
Keywords: Delta Winglet, Longitudinal Vortices, Thermal Enhancement Factor, Vortex Generator