EFFECT OF MICRO PIN-FIN GEOMETRY ON HEAT TRANSFER PERFORMANCE AND FLUID FLOW IN A SINGLE-PHASE HEAT SINK: NUMERICAL AND EXPERIMENTAL ANALYSIS

Resumo

The growing demand for electronic devices with high processing capacity with increasingly smaller
dimensions has been requesting solutions from the scientific community to dissipate the high rates of heat
generated in such devices, ensuring their integrity and functioning. Thus, research on applications in compact
heat sinks, such as micro pin-fins, has gained visibility, mainly associated with using environmentally friendly
working fluids. In this context, the current work analyzes the thermal and hydrodynamic behavior of HFE-7100
in a heat sink based on different shape pin-fins. Moreover, different micro pin-fins (with 350 μm height) arrays,
in-line and staggered configurations, are tested at different mass velocities. Thus, a numerical and experimental
study is carried out on the single-phase heat transfer and pressure drop characteristics. The numerical results
showed a good agreement with the experimental data for both geometries and operational conditions analyzed,
with a mean absolute error lower than 3.1% for heat transfer coefficient and 12.8% for pressure drop. The results
showed that the surfaces with staggered arrays present slightly better thermal performance than the in-line
arrays, probably due to the highest number of pin-fins. The staggering array yielded a higher Nusselt number at
the same mass velocity, which can be explained by the higher flow velocity and enhanced flow mixing.
Regarding the hydrodynamic aspects, the numerical data sets for in-line and staggered pin-fin configurations
have the same tendency, increasing with the mass flux. However, the in-line pin-fin values are higher, probably
due to the diamond pin-fin shape for the staggered configuration, which, compared to the in-line square shape
pin-fins, causes a reduced disturbance to the flow, giving smaller pressure drops. To conclude, both the in-line
and staggered configurations of the heat sink are reasonable solutions for the current cooling challenge, with an
advantage for the staggered configuration compared to the in-line configuration.