Optimized Longitudinal-Fin Heat Sinks Accounting for Non-Uniform Heat Transfer Coefficient.
optimization method is presented to determine the optimal fin spacing and thickness of a
fully-shrouded longitudinal-fin heat sink (LFHS) with an isothermal base that minimize
its thermal resistance under conditions of hydrodynamically and thermally fully
developed laminar flow. The thermal resistance of the LFHS is expressed in a
dimensionless form that allows it to be calculated ... read morealgebraically over a relevant range
of dimensionless parameters by utilizing a dense tabulation that has been prepared and
provided in the present work, eliminating the need to solve the complicated and time
consuming conjugate problem for each particular case. Therefore, the optimization method
in the present work requires only a fraction of the time that it is required for a CFD
brute force optimization. Prescribed quantities are the density, viscosity, thermal
conductivity and specific heat capacity of the fluid, the thermal conductivity and
height of the fins, the width and length of the LFHS and the pressure gradient, or, if
the optimal length of the LFHS is also of interest, the pressure drop across the LFHS.
The analysis assumes adiabatic shroud, constant thermophysical properties, cooling
driven by forced convection, negligible heat dissipation and axial conduction in the
flow, negligible axial conduction in the fin, and negligible temperature variation
across the thickness of the fin. Also, the width of the LFHS is assumed to be very large
compared to the pitch of the fins. The present study is distinct from previous work
because it does not assume a uniform heat transfer coefficient, but fully captures the
velocity and temperature fields by numerically solving the conjugate heat transfer
problem in dimensionless form, utilizing an existing approach, in order to compute the
aforementioned tabulation. The optimization method is illustrated by optimizing a LFHS
in the context of direct liquid cooling of
Thesis (M.S.)--Tufts University, 2015.
Submitted to the Dept. of Mechanical Engineering.
Advisor: Marc Hodes.
Committee: Chris Rogers, and James Adler.
Keywords: Mechanical engineering, and Applied mathematics.read less