Columbia, MD--Bowles Fluidics Corp.'s windshield washer nozzles are complex fluidic devices that rely on flow instabilities to oscillate the jet. The most critical design elements are the fan angle and cold weather performance required to meet automobile manufacturers' specifications for cleaning performance. In the past, meeting those requirements involved a lengthy trial-and-error process plus two days to build each prototype. Now Bowles uses computational fluid dynamics (CFD) to evaluate nozzle designs in a fraction of the time previously needed.
Initially, Bowles engineers analyzed an existing washer nozzle to determine the accuracy of CFD simulations. The results achieved with 2- and 3-D turbulent models matched those attained with actual experimental measurements. That accurate prediction of critical performance parameters demonstrated the potential to dramatically reduce design time and development costs, says Bowles engineer Anju K. Bawa. And it prompted the company to begin using CFD on actual design projects.
Today, Bowles engineers use FLUENT/UNS CFD software from Fluent Inc. (Lebanon, NH) to determine the viability of proposed approaches. The flexibility of the software's unstructured solver enables them to produce a model of a washer nozzle in less than a day, says Bawa. Modifications to a model to evaluate the effect of changing a design parameter typically take less than 30 minutes. The overall result, he says: nozzle designs that meet stringent specifications created in almost half the time previously required.