Conjugate heat transfer of a finned oval tube with a punched longitudinal vortex generator in form of a delta winglet—parametric investigations of the winglet

Abstract

To explore the influences of the angle of attack and the aspect ratio of a winglet, which is punched near the leading edge of the fin in a high performance finned oval tube (FOT) , on the heat transfer enhancement (HTE) and flow loss penalty (FLP) , three-dimensional flow and conjugate heat transfer in a FOT were calculated for a thermally and hydrodynamically developing laminar flow (Re = 300) by solving the Navier–Stokes and energy equations with a Finite-Volume Method in body-fitted grids. The conjugate heat transfer was realized by iterations of the energy equation in the flow field and of the conduction equation in the fin. Three angles of attack (β = 20°, 30° and 45°) and two aspect ratios (Λ = 1.5 and 2) were investigated. Velocity and temperature fields, vortex formation, local heat transfer distributions and global results are presented. The winglet with β = 30° and Λ = 2 provides the best ratio of HTE to FLP with ( j\\j0) \\ ( f\\f0) = 1.04.