Optimization of pin perforation(s) induced flow dynamic for effective thermal dissipation

Abstract

This study numerically investigates the 3D perforated pin-fin heat sink forced convection and the induced flow dynamics at Reynolds number ranging between 10 × 103<ReDh < 50 × 103 (Dh represents the hydraulic diameter). The preferences of single perforated pin diameter along pin diameter of Dpin/Dh = 0.188, 0.375 and 0.563, as well as the effect of multiple perforations N on pin of Dpin/Dh = 0.375 and N = 5 are studied. Response surface optimization is incorporated with two-equation turbulence model to explore the correlation between pin perforation diameter and the respective thermal dissipative preferences. Nusselt number maximization serves as the single-objective function to unveil the efficacy of optimized perforated pin-induced flow recirculation. Results show that optimum pin perforation diameter Dpf,opt exists as a function of Dpin and ReDh. Dpf,opt increases with larger Dpin but decreases at higher ReDh, owing to the size of flow recirculation induced leeward from pin. The ratio of Dpf,opt/Dpin is larger for smaller pin to effectively restructure the wider wakes coverage. The optimized flow dynamic in the lee from a perforated pin of Dpf = Dpf,opt is able to strengthen the thermal interaction within the perforation(s), weaken the capability of flow recirculation in trapping thermal energy, as a consequence, provide the most predominant thermal dissipation. Additionally, optimized pins of smaller Dpin and higher N value are more efficient in retrieving back the overheated situation to the targeted low temperature regime in a timely manner.