ABSTRACT The efficiency of smooth surface solar air heaters (SAHs) is often limited by viscous boundary layer formation and aerodynamic constraints, resulting in suboptimal thermal performance. This study introduces a novel enhancement technique using centerline perforated sine wave baffles as turbulators on the SAH surface to improve heat transfer and reduce flow resistance. The current work deals with experimental analysis of solar air heater performance using centerline perforated sine wave baffles placed as turbulators over the surface of solar air heater. Experimental analyses are conducted by varying Reynolds number, relative baffle pitch, relative baffle height, angle of attack, and relative perforation diameter, ranging from 3000 to 18,000, 8 to 14, 0.4 to 0.55, 10° to 45°, and 0.1 to 0.2 respectively. Collected experimental data are utilized to develop predictive machine learning models for Nusselt number, friction factor, and thermo-hydraulic analysis. Several models including Linear Regression, Random Forest, K-Nearest Neighbors, Adaptive Boosting, and Extreme Gradient Boosting are employed, with their performance evaluated using Mean Absolute Error, Mean Squared Error, Root Mean Squared Error, and R2. Extreme Gradient Boosting emerges as the most effective predictive model with an R2 value of 98.2%, alongside Mean Absolute Error and Root Mean Squared Error values of 8.025 and 11.3 respectively. Multi-objective optimization techniques such as Particle Swarm Optimization, Simulated Annealing, Genetic Algorithm, and Hybrid Genetic Algorithm are employed for this purpose. The optimized parameters obtained from Genetic Algorithm include Reynolds number, and values of 17,447, 8.37, 0.48, 25.045, and 0.11 respectively, aiming at maximizing and while minimizing. The results of genetic algorithms are being taken as optimal parameters which resulted in Reynolds number, relative baffle pitch, relative baffle height, angle of attack, and relative perforation diameter as 17,447, 8.37, 0.48, 25.045 and 0.11.
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