The Use of Computational Fluid Dynamics (CFD) Methods in Analysing Thermal Performance of Electronic Hardware

It is estimated that about 75% of failures in electronic systems are due to overheating.

The demand for smaller yet more powerful electronic systems leads to increased cabinet and component temperatures unless improvements are made to both cooling and heat transfer.

Tests to establish airflow patterns are difficult to set up and the results cannot be guaranteed.

This report details an alternative method of calculating airflow and heat transfer by computational fluid dynamic techniques.

It describes how to simplify complex components and layouts so that complete systems may be simulated, allowing modifications to the packaging and cooling strategy at the design stage, which can save both time and money.

The accuracy of the results obtained using CFD techniques can be very high, but this depends on the chosen representation of the geometry, the number of cells and the complexity of the hardware being modelled.

The report discusses the influence of these factors on the accuracy of the computed results and gives advice on the most efficient use of CFD.

Typical costs are given. A selection of CFD codes are reviewed, based on their suitability for predicting the thermal performance of electronic systems.

Methods of modelling cooling problems are also described.

Two sample simulations have been carried out - for a switched mode power supply and a domestic washing machine, using a package specifically designed for the non-CFD expert.

Finally, a "designer's guide" to cooling electronics is presented together with advice on fans, component spacing and coatings.

Useful conclusions are drawn and some CFD software suppliers are listed in an appendix.

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