Computer modelling of heat transfer in a MEMS based air micro-jet array impingement coolong device
by
R. Panneer Selvam and Joseph Khater
University 0f Arkansas
Coauthors: Simon Ang

The advancement of micro-electro-mechanical systems (MEMS) technology has brought forth, newer thermal management concepts in electronic industry. One form of MEMS structure is the micro-jet array (MJA) impingement cooling device. This MJA has 221 jets, each 0.277 mm in diameter, and uniformly distributed over a 2 cm x 2 cm x 0.15 mm thick silicon wafer. Results of the preliminary experimental investigation for some sample cases of air flow (up to 4 g/s) and heat flow (up to 75 W) have been published by Leland et al. (1999). The mechanics of fluid and heat flow in the MJA is not well understood. Computer modeling is done in order to understand its thermal transport behavior and to design an efficient MJA. The flow and heat transfer behavior in the MJA is computed by solving the Navier-Stokes (NS) equations using finite difference method. The details of the computer modeling issues will be presented in the final paper. Currently, grids ranging from 300, 000 to 800, 000 are used to understand the flow behavior. The measured temperature data at specific points are compared with computed results to verify and validate the model. The computed temperatures are in reasonable agreement with the measured results. An unexpected flow pattern was discovered upon disassembly of the MJA device. The computer model has yielded valuable information on this flow phenomenon and heat transfer within the device. The details of the computed flow and temperature distribution will be presented along with a visualization technique to explain the flow behavior. A method to improve the current MJA configuration is also investigated by changing the size of the jet holes at certain places. The impact of this change will also be presented.

Acknowledgment:
The study has been supported by ARPA grant no: MDA 972-96-1-0008 through HiDEC, University of Arkansas.

Date received: April 15, 1999

Copyright © 1999 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cacr-67.