RSM and CFD Procedures for Assessing Free Convection and Entropy Generation Performance in a Porous Cassini Oval Annular Pipe

Free convection and entropy generation inside a complex annular pipe were vital for different applied thermal engineering systems. The current study investigated the thermal and flow characteristics inside a porous Cassini oval annular pipe, considering response surface methodology (RSM) joint with CFD. The multi-objective optimum design was a novel consideration to improve heat transfer in terms of Nusselt number (Nu_mR) and heat transfer rate (QR) with a reduction in entropy generation (EnR) and frictional losses (SFCR) under different design parameters, such as aspect ratio (0.08 ≤ AR ≤ 0.2), angular rotation (0° ≤ θ ≤ 90°), porosity (0.15 ≤ ɛ ≤ 0.95), and pore per inch (10 ≤ PPI ≤ 30). The main data indicate that the aim optimum design is achieved in the enhancement of Nu_mR and QR by nearly 23.78 times and the reduction in SCFR by approximately 91.45% with appropriate EnR by about 1.0227 times. This demonstrate the resilience of design's hydrothermal performance under different applied operation temperatures (10 ≤ ΔT ≤ 30). Thus, the multi-objective optimization function is a useful and novel proposed process for optimizing the hydrothermal and entropy performance of a porous Cassini oval annular pipe under several design and operation parameters.