EXPERIMENTAL VALIDATION OF NUMERICAL HEAT TRANSFER PREDICTIONS FOR SINGLE- AND MULTI-COMPONENT PRINTED CIRCUIT BOARDS IN A FORCED CONVECTION ENVIRONMENT: PART I - EXPERIMENTAL AND NUMERICAL MODELLING

Coupling the electronic industries desire to produce more compact and reliable systems using shorter design cycle times, highlights the need for efficient thermal design tools. Such development trends are driven by technological advances, particularly at die level where increasing power dissipation densities push the need for forced convection air-cooling of electronic components. While the analysis of such conjugate heat transfer problems is highly complex, Computational Fluid Dynamic (CFD) based numerical predictive techniques have the potential to meet the outlined demands. However, relying solely on this approach without supporting experimental analysis still remains an unreliable design strategy, as the full capabilities of these evolving tools need to be carefully evaluated for realistic electronic systems. This can only be achieved by comparing CFD predictions to accurate experimental benchmark data, thereby enabling confidence to be established in both the modelling methodology and numerical code. In this study, benchmark test cases are presented for singleand multi-component, FR-4 Printed Circuit Boards (PCBs), populated by three standard package types (SO16, TSOP48 and PQFP208) and exposed to a 2 m/s, forced airflow parallel to the PCB plane. Benchmark criteria used to validate prediction accuracy were based on the parameters of die junction temperature and component-PCB surface temperature gradients. The experimental equipment and procedure used, along with the numerical modelling techniques applied are described in this paper, while the results are presented and discussed in the accompanying Part II, [Rodgers et al., 1999a]. The motivation for this study and subsequent direction taken, is due in part to the industrial need, but also to an extensive literature review which is summarised in the opening section.

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