Thermal analysis of wavy finned heat sinks through cross-cut modifications under natural convection
DOI:
https://doi.org/10.15282/jmes.20.2.2026.1.0869Keywords:
cfd, heat sink, wavy fin, Natural ConvectionAbstract
Wavy fin heat sinks offer significant potential for thermal management due to their enhanced surface area compared to conventional straight-fin designs. However, the effect of surface area on thermal resistance is not straightforward since thermal resistance depends on the inverse product of surface area and the convective heat transfer coefficient. This study investigates the relationship between surface area, convective heat transfer coefficient, and thermal resistance for wavy fin heat sinks under natural convection. Experimental tests were conducted on a l parallel-fin heat sink (HS1) and a wavy-fin heat sink (HS2) using a polyimide heater supplying 4 W of input power. Thermal resistance is determined from steady-state temperature measurements using three thermocouples located at the heat sink base. Despite having an approximately 10% greater surface area, HS2 exhibited a thermal resistance of 14.85 K/W, about 4.7% higher than HS1 (14.19 K/W). This highlights that increased area alone does not guarantee improved performance. This is attributed to a lower convective heat transfer coefficient (8.38 vs. 9.71 Wm⁻²K⁻¹) caused by restricted airflow within the wavy fin channels. Three-dimensional steady state computational fluid dynamics simulations on four cross-cut variants of HS2 are performed to investigate the effect of geometric modifications on the convective heat transfer performance. The HS2B showed a reducing thermal resistance by up to 3% (5.57 K/W) while slightly decreasing surface area compared to HS2(16.21 K/W). These results demonstrate that effective heat sink design under natural convection requires the balancing surface area and convective heat transfer coefficient.
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