Hollow trapezoidal baffles in a rectangular channel: Thermal/hydraulic assessment with ANN numerical approach

Abstract

In this study, thermal/hydraulic performance (THP) of a heated bottom surface channel, on which hollow straight, elliptic, and wavy top surface trapezoidal baffles are attached, have been investigated. Artificial neural network modeling (ANN) and 3D ANSYS numerical valuations are presented and validated using experimental data obtained by Sahin et al. (2019). Six parameters are studied: baffle height (H), baffle width (S), baffle length (L), corner angle (α), inclination angle (β), and Reynolds number (Re). This study is carried for both aligned and staggered baffles configuration. Air is considered to be the working fluid at a range of Reynolds number (5 × 103 ≤ Re ≤ 2.3 × 104). Backpropagation technique used to determine the optimal ANN size with the Bayesian regularization algorithm. Results show that the most effective parameters on THP are Re, α, and H. Based on the thermal hydraulic efficiency values, the optimum condition is obtained at α= 16°, β = 0°, and baffle dimensions of H = 20 mm, L = 25 mm, S = 26 mm. The average value of thermal enhancement factor (TEF) shows that the staggered arrangement is superior to aligned one for all baffle shapes at the optimum condition. The largest TEF is 1.2 which is captured for the case of the wavy top surface trapezoidal baffles in staggered arrangement at Re = 5000.