Numerical study and prediction of thermohydraulic performance in crossflow over hybrid tube bundles

In this study, the hydrodynamics and thermal behavior in the crossflow of air passing over hybrid tubes in the staggered configuration were numerically investigated. CFD (Computational Fluid Dynamics) study were conducted with the help of the ANSYS Fluent program. In the study, 12 different tube bundle models were created with a combination of circular and wing-shaped tubes. The wing-shaped tubes were placed in the tube bundle at different attack angles (θ: 0° and 180°). Reynolds numbers in the range of 4000 ≤ Re ≤ 12,000 were used. To observe the effects of hybrid tubes and Reynolds numbers on thermal and flow fields, velocity, pressure, and temperature contours were acquired. According to the findings, Nusselt number (Nu) and performance criteria (PC) increased, and friction factor (f) decreased with increasing Re for all tube bundle models. The friction factor of hybrid tube bundles was higher than wing-shaped tube bundles but considerably lower than circular tube bundles. Among the hybrid models, the best heat transfer was obtained in Model 6, the lowest friction factor in Model 11, and the best PC in Model 4. Also, three different stacked ensemble models were created to predict Nu, f, and PC values for CFD analysis. These models are the ensemble of XGBoosts, the ensemble of DNNs, and the ensemble of DNN, XGBoost, and RF. This study revealed that ensemble of XGBoosts is more beneficial than the other in the CFD analysis.