The impact of vortex generator positioning and heated surface orientation on thermal performance and flow dynamics in asymmetrically heated duct

Abstract

This computational investigation primarily explores the impact of three factors on thermo-hydraulic performance: the dimensionless distance ratio (z/L = −0.1 to 0.5), Heated Surface [HS] orientation (HS-Up, HS-Down), and Delta Winglet [DW] positioning (DW-PU, DW-PD). The numerical model applies steady-state RANS and energy equations with the (SST) k-ω turbulence model, assuming incompressibility, constant thermophysical properties, and ignoring radiation and buoyancy effects. A comprehensive analysis of resulting data reveals that the DW-PD configuration yields lower Darcy friction factors across all z/L ratios compared to DW-PU layout, exhibiting reductions of 6.35 % at z/L = −0.1 and 3.49 % at z/L = 0.5. The DW-PD setup with HS-Down demonstrates the best thermal performance among all configurations and dimensionless distance ratios (except z/L = −0.1). Moreover, the optimum dimensionless distance ratios for achieving the highest Nusselt numbers are determined as z/L = 0.1 for HS-Up and z/L = 0.2 for HS-Down under both configurations. The computational data indicates that the difference between the maximum and minimum Thermal Enhancement Factor [TEF] is approximately 23.78 % and the highest TEF = 1.25, is achieved with the utilization of DW-PD at z/L = 0.2 for HS-Down at Re = 5000. This study underscores the critical significance of examining all these parameters to attain the highest thermal performance.