Design optimization of a circular enclosure with flexible fins: Fluid-Structure interaction and heat transfer analysis using rotating frame modeling

This study optimizes heat transfer in a circular vessel containing cold and hot cylinders, a rotating frame, and flexible baffles designed to enhance thermal exchange. Optimized design of such topics improves the performance of heat exchangers. The investigation analyzes the impact of rotational speeds ( ω * = 10 - 400), distances of the cylinders from the frame axis ( e * = 0.32 – 0.43), and Rayleigh number ( Ra = 10 3 – 10 5 ) on the heat transfer. Time-dependent equations are discretized and solved using the finite element method with rotating meshes. The Nelder-Mead optimization method was utilized to identify the optimal conditions that enhance the system's thermal stability and heat exchange efficiency. This approach establishes a foundation for improved thermal designs for applications requiring high dynamic thermal responsiveness. The results indicated that the maximum heat exchanges were obtained at e*= 0.32378 and ω*=366.48 for Ra = 10 3 , and at e*=0.32 and ω*=379.43 for Ra = 10 5 . The Nusselt numbers for these conditions were 5.32 and 7.7, respectively. Therefore, to achieve optimal heat transfer, the operating conditions, such as the frame's angular speed and the cylinder's distance, should be optimized for each Rayleigh number.