A benchmark study of computational fluid dynamics predictive accuracy for component-printed circuit board heat transfer

The application of computational fluid dynamics (CFD) analysis for the ther mal design of electronic systems has the potential to enable accurate solut ions to be generated and quickly assessed. With the use of validated numeri cal models, numerical analysis can also be used to provide useful insights into heat transfer processes which could otherwise be difficult to characte rize experimentally, However, the capabilities of the CFD tool need to be c arefully evaluated so as to provide a degree of confidence in prediction ac curacy, thereby minimizing the need to qualify thermal designs. Such an evaluation is presented in this paper, which represents the culmina tion of a benchmark study by Rodgers et al, [1]-[4], This overall study ass esses the predictive accuracy of a commercial CFD code for both natural and forced convection heat transfer of single- and a multicomponent printed ci rcuit boards (PCBs), Benchmark criteria were based on both component juncti on temperature and component-PCB surface temperature profiles [1]-[4], In t he context of the overall study, this paper brings these analyses together to provide a more comprehensive assessment of CFD predictive accuracy for c omponent junction temperature. Additionally the validated numerical models are used to further investigate the sensitivity of component heat transfer to convective environment, both natural and forced, component position rela tive to the PCBs leading edge, impact of upstream aerodynamic disturbance, and the representation of PCB FR4 thermal conductivity. The significance of the listed variables is quantified by analyzing predicted component energy balances. Qualitative descriptions of the fluid now fields obtained using a novel paint Blm evaporation technique are also provided in this study. Bo th analyses yield new insights of the heat transfer processes involved and sources of numerical error.