Accession Number : AD1026568


Title :   Novel Natural Convection Heat Sink Design Concepts From First Principles


Descriptive Note : Technical Report


Corporate Author : Naval Postgraduate School Monterey United States


Personal Author(s) : Fletcher,Derek E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1026568.pdf


Report Date : 01 Jun 2016


Pagination or Media Count : 67


Abstract : This was a two-part numerical study using ANSYS Fluent to develop novel heat sink concepts from first principles. The objective of this research was to highlight geometric structures that incorporate the principles of the stack effect to improve the heat transfer capability of a heat sink under natural convection.The first part investigated the heat transfer/fluid flow characteristics of vertically aligned tubes. The gaps between tubes break up the thermal and velocity boundary layers and the moving fluid within a tube entrains the cooler ambient air surrounding the gap, thus increasing mass flow rate and average Nusselt number through each tube. The optimal gap-to-length ratio varies depending on the number of tubes in the system. The second part built upon the insight gained to develop heat sinks to compare to pin-fin heat sinks. A tube system heat sink provides a significant improvement in the heat transfer capability over a circular pin-fin arrangement, demonstrated by an increase in both the overall heat transferred and average heat transfer coefficient. The principles discussed in this study have the potential to expand the capability of natural convective heat transfer.


Descriptors :   fluid flow , boundary layer , heat transfer , heat transfer coefficients , computational fluid dynamics , fluid dynamics , thermal resistance , buoyancy , flow rate , heat sinks , mass flow , numerical analysis , reynolds number , turbulent flow , heat flux , laminar flow , physical properties


Subject Categories : Air Condition, Heating, Lighting & Ventilating


Distribution Statement : APPROVED FOR PUBLIC RELEASE