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Browse Prior Art Database

High Performance Convective Surface

IP.com Disclosure Number: IPCOM000104823D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

Chrysler, GM: AUTHOR [+2]

Abstract

Disclosed is a method of increasing the amount of apparent heat transfer area of a pin array by over 33 percent while at the same time providing an enhanced convective heat transfer coefficient. Applications in the electronic industry include high-end systems with modules requiring liquid cooling (i.e., coldplates, heat exchangers) and advanced work stations constrained to air cooling. In the latter case, air impingement onto tightly packed pin fin heat sinks is considered state-of-the-art. This disclosure will significantly extend this heat sink technology.

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High Performance Convective Surface

      Disclosed is a method of increasing the amount of apparent heat
transfer area of a pin array by over 33 percent while at the same
time providing an enhanced convective heat transfer coefficient.
Applications in the electronic industry include high-end systems with
modules requiring liquid cooling (i.e., coldplates, heat exchangers)
and advanced work stations constrained to air cooling.  In the latter
case, air impingement onto tightly packed pin fin heat sinks is
considered state-of-the-art.  This disclosure will significantly
extend this heat sink technology.

      The essence of this disclosure is to add apparent heat transfer
area to the tightest pin array by threading the pins.  For
illustration purposes, the figure depicts an air-cooled multi-chip
module 1, with extended heat transfer surface pins 2, made of
standard M2 screws.  Internal to the module are electronic chips 3,
mounted to a chip carrier 4 with flexible I/O connections 5.  Thermal
contact between the chips and the module is made via a thermal paste
6 on each chip.  Impingement air 7 is directed down through the pins
and exhausts 8 through all sides of the pin package.  Since the
packaging of the pins is very tight (D x 1.25D staggered grid), the
small fins created by the thread may behave as extended surface area.
If the pin pitch was large relative to the fin (thread) length, then
most likely the coolant would not flow between the fins.  A standard
M2 screw has about 33 percent more surface area than a plain fin of 2
millimeters in diameter.

      The threading of the pins provides not only added surface area
for convection, but also enhances the convective heat transfer
coefficient.  The fins impose a secondary flow component normal to
the prevailing direction.  This further enhances mi...