Better, more user-friendly software for heat-sink design is fast taking hold. The surge toward greater power densities puts the squeeze on larger board-cooling solutions, but developers continue to stay a few steps ahead in providing the tools for thermal analysis and design.

Members of the Power Sources Manufacturers Association, meeting last month, "recognize the need for sophisticated thermal analysis and design software now just to keep even into next year," said Chris Soule, marketing manager for Aavid Thermal Technologies. And system designers will have their challenges soon enough, including the immediate need of the industrial drive business for more efficiently cooled IGBTs and, more exciting, the demands for cooling entire boards with one customized structure.

For system designers, the problem is simply defined. Eliminate brute-force, cut-and-try techniques and you save money by reducing design time and time-to-market. But what's the best technique?

The method with the acknowledged inside track is computational fluid dynamics (CFD). While an initially expensive workstation tool, CFD performs a rigorous (no-shortcut) analysis using numerical methods to solve the equations of motion in fluids and gases, and it provides unsurpassed accuracy for the most demanding applications.

Flomerics, which first used CFD in the late 1980s, recently announced its version 2.2, which speeds up analysis by a factor of 2 to 3 over its previous edition. Fluent/Aavid's advanced CFD version, Icepak 3.1, adds macrofunctions, multiprocessing capability, more complicated geometries and more complex flows to get the job done 20 percent faster than the previous 3.0 version. Version 3.2 is expected in May.

"CFD is a powerful tool, but we've responded to everyday users in a different way," said Ken Hermann, vice president of marketing at R-Theta, pointing to his company's interactive, online Web offering, R-Tools. Although the demands for suitable heat sinking are becoming more involved, Hermann said the software-based on analytical heat transfer models, Fourier series and the steady-state solution of the Laplace equation-is practical for 80 percent of all designs.

Either way, vendors are determined to keep system designers out of the heat.