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ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
EXPERIMENTAL AND NUMERICAL STUDY OF HEAT TRANSFER AND PRESSURE DROP IN MICRO PIN-FIN HEAT SINKS UNDER SINGLE AND TWO-PHASE FLOW CONDITIONS
Submission Author:
Jessica Martha Nunes , SP
Co-Authors:
Jessica Martha Nunes, Isabelle Guimarães da Silva, João Batista Campos Silva, Jeferson Diehl de Oliveira, Jacqueline Copetti, Elaine Maria Cardoso
Presenter: Isabelle Guimarães da Silva
doi://10.26678/ABCM.ENCIT2022.CIT22-0331
Abstract
Due to microscale effects, the segmented microchannels or micro pin fins heat sinks came out as a high thermal management solution. In this context, the present work analyzes the influence of different heights of micro pin fins with an aligned array and investigates their influence on pressure drop and heat transfer behavior. The HFE-7100 is used as the working fluid, and the pressure drop and surface temperature behavior are analyzed for different mass fluxes and inlet subcooling. The CFD software ANSYS FLUENT® was applied for single-phase flow to compare it with the experimental data. The numerical analysis shows that the highest micro pin fins configuration provides a more uniform wall temperature distribution and decreases by around 18.6% compared to the lowest configuration. There is a good agreement between the experimental results and the numerical analysis, with a mean absolute error of 6% for all the considered parameters. For the two-phase flow condition, for the highest subcooling, an increase in mass flux causes an enhancement in the heat transfer for low heat flux; by increasing heat flux, there is a gradual predominance of boiling heat transfer over convection as the heat transfer mechanism. The pressure drop drastically increases with the vapor amount flowing into the system, regardless of the pin fin height; the boiling curves for the higher fin height show a much smaller slope and a smaller wall superheat than the fin with the smallest height, and consequently, a high heat transfer performance. For lower inlet subcooling temperature, a larger region of the heat sink is filled with vapor, degrading the heat transfer performance compared to higher inlet subcooling temperature.
Keywords
Convective Boiling, HFE-7100, pin fin geometry, pressure drop, Heat transfer coefficient
