Experimental and numerical study on thermal performance of new envelope and triangular vortex generators with different pitch and angle of attack

Abstract

In this study, experimental work has been carried out to analyze the effect of different Vortex Generators (VGs) shapes (including novel envelope shape geometry), pitch ratios, and angles of attack on various thermohydraulic parameters of the channel, and the performance of the thermoelectric generator (TEG) system. The geometry of VGs introduced in the study are triangular (Delta or D-shape) and envelope (M−shape). Numerical analysis of the temperature, pressure, and velocity distribution has been carried out to understand the effect of the vortex generators. In the study, the channel has been divided into control volumes to observe the variation in the hot gas temperature, heat transfer coefficient, percentage Nusselt number change, pressure drop, thermal enhancement factor (TEF), cost-benefit ratio (CBR), and power output of the TEG system due to the different configurations employed. Triangular VG exhibits the maximum heat transfer coefficient of 342.41 W/m2K at pitch ratio 2 and 60° angle of attack. Also, the highest increment in percentage Nusselt number of 4.2 % is shown by triangular VG (p = 2, θ = 60°). Maximum pressure loss occurs for VGs with θ = 90° for all configurations, out of which the D-shape causes the highest loss due to the largest frontal area. Triangular winglet vortex generators at 45° showed 7.6 %, 6.17 %, and 46.16 % higher thermal enhancement factor (TEF) than at 30°, 60°, and 90° respectively. Hot air at 30° had the lowest cost-benefit ratio. The maximum TEG power output of 1.5 W is observed for D-shape VG at p = 2 and θ = 60°, which is 267.24 % higher than that of the flat geometry channel flow. Therefore, the channel employed with D-shape VG at p = 2 and θ = 60° is settled for the best configuration for the overall parameters studied. The study also suggests using VGs for enhanced performance of a TEG system. © 2024 Elsevier Ltd