Thermo-fluid analysis of micro pin-fin array cooling configurations
for high heat fluxes with a hot spot
Abas Abdoli, Gianni Jimenez, George S. Dulikravich
*
Florida International University, Department of Mechanical and Materials Engineering, MAIDROC Laboratory, Miami, FL 33174, USA
article info
Article history:
Received 23 July 2014
Received in revised form
22 December 2014
Accepted 22 December 2014
Available online
Keywords:
Electronics cooling
Micro pin-fin
High heat flux chip
Hot spot
Conjugate heat transfer
abstract
Effect of micro pin-fin shapes on cooling of high heat flux electronic chips with a single hot spot was
investigated numerically. Hydrothermal performances of different micro pin-fin shapes were evaluated.
Circular shape, hydrofoil shape, modified hydrofoil shape, and symmetric convex shape were the cross
section shapes used for micro pin-fins. All cooling configurations had the same staggered arrangements
for micro pin-fins. An electronic chip with a 2.45 2.45 mm footprint having a hot spot of 0.5 0.5 mm
at its centre was used for simulations. Uniform heat flux of 2000 W cm
2
was applied at the hot spot. The
rest of the chip was exposed to 1000 W cm
2
uniform heat load. The cross section area of the circular
shape and hydrofoil shape micro pin-fins was kept the same to have a fair comparison. Convex and
hydrofoil shape designs showed significant reduction in the required pumping power as well as the
maximum required pressure. In the last case, the height of micro pin-fins was increased from 200 mm to
400 mm to remove 100% of the total heat load via convection, and at the same time keep the maximum
temperatures within an acceptable range.
© 2014 Elsevier Masson SAS. All rights reserved.
1. Introduction
Three-dimensional (3-D) integrated circuits (ICs) are believed to
be the best way to overcome barriers in inter-connect scaling and
keep Moore's law ticking by providing an opportunity for
continued higher performance ICs in the semiconductor industry
[1]. Smaller size, higher performance, better functionality and
lower consumption of power are some of the major advantages of
3-D ICs. On the other hand, increasing demand for removing heat
from 3-D ICs has become the major challenge in this field and has
constrained their applications. The next generation of the elec-
tronic chips is expected to produce heat fluxes up to 500 W cm
2
as
the background and more than 1000 W cm
2
at hot spots [2,3].
Sahu et al. [4] applied a hybrid cooling scheme which combines
microfluidic and solid-state cooling techniques in cooling hot spots
with the heat flux close to 250 W cm
2
. In other research, Sahu et al.
[5] studied a liquid-thermoelectric hybrid cooling method for hot
spots having heat fluxes of more than 600 W cm
2
. They reported
that liquid-thermoelectric hybrid cooling showed better results for
higher heat fluxes at hot spots. Abdoli and Dulikravich [6]
performed multiobjective optimization for multi-layer straight and
branching counterflow microchannel configurations with 67
design variables to maximize heat removal capacity, while mini-
mizing temperature non-uniformity and coolant pumping pressure
drop. They also optimized the multi-layer through-flow micro-
channels for heat fluxes up to 1000 W cm
2
[7]. Abdoli et al. [8] also
performed a fully 3-D thermal-fluid-stress-deformation analysis
for cooling chips with 1000 W cm
2
background heat flux and up to
2000 W cm
2
heat flux at the hot spot. They reported that multi-
floor microchannels are capable of cooling such chips without
exceeding the maximum allowable stresses.
Micro pin-fins have shown very promising results in conveying
heat from multiple layers to the heat sink [9,10]. Alfieri et al. [11]
numerically investigated cooling of 3-D stacked chips with
50 W cm
2
background and 125 W cm
2
hot spot heat fluxes. They
studied the influence and implications of the integrated water
cooling, micro pin-fins distribution and sizes also influence tem-
perature of hot spots. Alfieri et al. [12] in another research
modelled vortex shedding in water cooling of 3-D integrated
electronics. Zhang et al. [13,14] experimentally investigated effects
of silicon micro pin-fin heat sink with integrated TSVs in cooling
high power chips. Dembla et al. [15] also studied the fine pitch TSV
integration in silicon micro pin-fin heat sinks for 3D ICs with
100 W cm
2
heat load.
* Corresponding author.
E-mail addresses: aabdo004@fiu.edu (A. Abdoli), gjime006@fiu.edu (G. Jimenez),
dulikrav@fiu.edu (G.S. Dulikravich).
Contents lists available at ScienceDirect
International Journal of Thermal Sciences
journal homepage: www.elsevier.com/locate/ijts
http://dx.doi.org/10.1016/j.ijthermalsci.2014.12.021
1290-0729/© 2014 Elsevier Masson SAS. All rights reserved.
International Journal of Thermal Sciences 90 (2015) 290e297