Project leader: Professor Bahram Moshfegh
For information, contact: Dr Hans Jonsson
Supported by: University of Gävle and KK-Foundation
Introduction The current trends towards the miniaturization of electronic devices, greater functionality, increased chip-level heat fluxes and increasing processing speed fluxes make the thermal management a bottleneck in the system performance. This fact makes the thermal management of electronics an important issue for companies. Despite an increased interest in other cooling technologies air is still the preferred cooling fluid and will continue to be so in the future. Cooling of electronic components by means of forced channel flow with extended surfaces has been studied extensively in the past. In a typical electronic system, the Printed Circuit Board (PCB) will contain one or a very few high heat dissipating components, typically a processor, and many more peripheral lower dissipating electronic components. The overall cooling strategy thus must not only match the overall power dissipation load, but also address the requirements of the "hot" components. In most equipment, hot components are equipped with extended surface heat sinks. In this proposal, we will explore the combined use of forced convection channel flow between PCB's to manage the overall thermal load with "spot" cooling using jet impingement on an extended surface heat sinks. By combating the whole thermal load with forced channel flow, excessive flow rates will be required. The objective of this project is to investigate if targeted cooling systems such as impinging jets can improve the thermal performance of the system. The purpose of the present study is to investigate if an impinging jet and a low-velocity channel flow with pin fin heat sinks works in harmony.
The system approach consists of both measurement and numerical prediction methods. A combination of traditional point-measuring and newly developed whole-field measuring techniques will be used. Due to the highly unsteady flow characteristics, the heat transfer of the impinging jet is strongly time-dependent. As a result the Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation and Large Eddy Simulation (LES) will be used for predictions. The results from measurements will be used for the calibration and validation of the CFD. By a combination of CFD and experimental data, we can obtain a thorough understanding of the physics in this complex flow. Results from experimental and prediction methods will be used to develop simplified mathematical and flow network models.