Introduction of a New Fin Design for a Cooler

Introduction of a new cooler's fin: from research to industrialization Compact plate–and-fin heat exchangers are central components in automotive and industrial cooling systems due to their high thermal effectiveness and compact geometry. Nonetheless, their performance is often constrained by relatively high air-side thermal resistance, making the optimization of fin geometry a decisive factor in advancing efficiency. This thesis introduces and evaluates a novel reduced-height wavy fin (7.5 mm) as a potential replacement for the conventional 10.2 mm fin design, with the dual objective of enhancing air-side thermal–hydraulic performance and verifying its feasibility for large-scale manufacturing. The study adopts a combined computational and experimental methodology. First, the fin geometry was developed using PTC Creo, designed with smooth sinusoidal profiles to facilitate meshing and minimize numerical instabilities. High-fidelity CFD simulations were carried out in STAR-CCM+ using a steady-state RANS solver with the SST k–ω turbulence model. The computational domain was based on a representative unit cell of the plate-fin passage, incorporating boundary-layer refinement, prism layers, and a structured meshing strategy. A grid-independence study was conducted to ensure accuracy, and simulations were run over a range of flow rates to evaluate thermal and hydraulic performance indicators. In parallel, two full-scale radiator cores—one with the baseline 10.2 mm fins and another with the proposed 7.5 mm fins—were fabricated. The manufacturing process reflected industrial practices, including aluminum fin stamping, bar-and-plate stacking, and vacuum aluminum brazing. Post-braze inspection and leak testing ensured structural integrity and fluid tightness of the prototypes. A dedicated experimental facility was constructed to evaluate the prototypes. This included a vertical airflow tower equipped with a variable-speed fan, coolant circulation loop, and comprehensive instrumentation. Thermocouples measured air and liquid inlet/outlet temperatures, Pitot tubes and static pressure taps recorded dynamic and static air pressures, and differential pressure sensors monitored air-side and liquid-side pressure drops. Flow meters measured coolant and airflow rates. Tests were performed under systematically varied fan speeds, coolant flow rates, and inlet coolant temperatures. From these experiments, key performance parameters—air-side pressure drop, heat transfer rate, Reynolds number, Prandtl number, Colburn j-factor, and friction factor—were obtained. These data were then compared with CFD predictions to validate numerical models and assess the viability of the reduced-height fin for future heat exchanger applications.