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Ehsan Khavasi

Mohammad Taghilou, Ehsan Khavasi
Thermal behavior of a PCM filled heat sink: the contrast between ambient heat convection and heat thermal storage  

This work is dedicated to present a numerical investigation on the PCM-filled heat sink with an emphasis on the ambient convective heat transfer. The main motivation to address this is a contrast between the PCM capacity to heat absorption and the convection ability to deliver heat to the ambient. For this purpose, three different heat sinks with plate and needle fins considering different convective heat transfer coefficients in the range of 5-250 W/(m2·K), under different heat fluxes are intended. Results find a certain amount of heat transfer coefficient at any using time and heat flux, which justifies the use of PCM for fewer amounts of that. This certain amount is called as a design heat transfer coefficient hd. Results show that the variation of hd is a descending function of using time, so that for a heat sink with plate fins and q“=9000 W/m2, the amount of hd is 182 and 36 W/(m2·K) at t=100 and 700 seconds, respectively. It is also shown that in low heat fluxes, the increase in the heat flux causes an increase in the amount of hd so that as the heat flux increases from 1000 to 2500 W/m2, the amount of hd increases from 50 W/m2 to 60.23 W/m2. But in high heat fluxes, any increment of heat flux reduces the design heat transfer coefficient. For example, by increasing the heat flux from 5000 to 12000 W/m2, the amount of hd decreases from 46.75 W/m2 to 30.94 W/m2 at t=700 seconds.



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