CFD for the Masses

Not many engineers would think of computation fluid dynamics as an easy discipline. In fact, some of the analysts who work on the toughest flow and heat transfer problems do little else. But does CFD have to be as specialized as it's become? The engineers and software developers at Blue Ridge

"We've focused our efforts on making CFD more acceptable to the masses," says Ed Williams, the company's president and cofounder. Over the past five years, Williams and his team at Blue Ridge have created a new kind of CFD software that addresses the needs of non-specialist design engineers who want to run flow or thermal analyses early in the design process.

Called CFdesign, the software takes much of the sting out of CFD set-up. For one thing, it closely integrates with the geometry kernel of existing CAD systems, using native CAD data as the basis for the simulations. For another, it maintains an associative relationship with the CAD system, so that changes made to the model are reflected in the simulation's mesh and boundary conditions.

CFdesign also automates some of the tasks usually left to the discretion of an experienced analyst. For example, it generates a suitable mesh without user input. "The design engineer doesn't want to know about meshing," says Len Whitehead, Blue Ridge's director of operations. Or to take another important example, CFdesign has automatic convergence algorithms that decide when the analysis has run its course. "The software tells you when the analysis is finished," he says.

Best of all, engineers interact with the software "in their own language," says Rita Schnipke, Blue Ridge Numerics' cofounder and chief technology officer. Rather than specialized fluid dynamics inputs, engineers work with familiar engineering units. Thus, the software asks for inputs like GPM and PSI rather than Reynolds numbers and accelerators.

Finally, the software includes a design communication and review tool that allow engineers to view simulation results dynamically and in any cutting plane they choose. They can also share the results of their work as an HTML report for easy viewing by audiences that may lack CFD and CAD software.

The whole analysis process can take just a few minutes for a single iteration. In a recent demo on a notebook PC, Whitehead ran through the analysis of a fan blade in a sheet-metal housing in less than six minutes.

Despite its emphasis on ease-of-use, Blue Ridge didn't skimp on the physics. According to Schnipke, a PhD engineer who has contributed to more than 30 CFD codes over the course of her career, the software uses the same Navier-Stokes equations as other analysis software. She goes on to describe Blue Ridge's finite element solver as a finite element code that makes use of some finite volume tricks. "The truth is, we can model most anything that flows," she says.

That long list includes creeping to supersonic fluid flows. It includes compressible liquids. It includes a wide variety of heat transfer simulations, among them Joule heating. It includes electrical potential problems, such as current flow and voltage drop. Finally, it includes an expanding variety of motion problems—in which a solid object moves through a fluid. "This is not CFD for dummies," Schnipke says.

And one look at the company's growing roster of users backs her up. Customers include well-known OEMs such as Canon, Mitsubishi, Motorola, Hitachi, and Phillips. Applications have included medical imaging equipment, automotive systems, pumps, turbines, compressors, packaging equipment, HVAC systems, plumbing fixtures, and more. And it's started to make a mark in racing. Richard Childress Racing uses it. And so does Trek, the company that makes Lance Armstrong's bikes.

"It's really a diverse group of companies and applications," says Williams. And he predicts that the list of users will continue to grow at a rapid clip. "Wherever you have heat transfer or fluid flow problems, our chances are good," he says.

For more information including demos of CFdesign , visit: http://rbi.ims.ca/4395-528