Fluid Simulation Reduces Valve Prototype Development Time from 3 Months to 1 Day
Aerospace valve manufacturer Shaw Aero Devices, Inc., Naples, Florida, saved at least $9000 and three months in prototyping costs by using Flomerics' FloEFD computational fluid dynamics (CFD) software to iterate to an optimized design. The CFD results for each iteration provided insights into how the design could be improved. Rob Preble, Project Engineer for Shaw, created a design that provided the required pressure drop without the need to build a single hardware prototype. "CFD simulation dramatically reduced the time needed to meet our customer's demanding specifications," Preble concluded. "We moved from the beginning of the project to the development of an acceptable software prototype in only one day."
Shaw Aero Devices designs, develops and manufactures a wide range of products in the areas of fuel, oil and water/waste systems and components. Shaw's customer was interested in purchasing a large quantity of a solenoid valve similar to one of their standard products for an unmanned aerial vehicle (UAV). The customer specified a pressure drop of 0.75 pounds per square inch (psi) at a flow rate of 4.45 gallons per minute (gpm) while Shaw's standard valve measured out at 6.09 psi. In the past, this would have required building and testing a series of designs in an effort to eliminate constrictions with no guarantee of success.
Instead, Preble simulated fluid flow within the original standard product design. FloEFD reduced the time required to simulate flow by analyzing the model and automatically identifying fluid and solid regions without user interaction. Preble then ran a series of simulations of the original design at flow rates from 1 to 5 gpm and the simulation predicted the pressure drop with an error of less than 10% at every point. Preble then created a series of design iterations, changing each design to reduce pressure drop guided by the CFD results of the previous iteration.
For example, in viewing the cut plot of the pressure gradient of the first design run, Preble noticed that the angled wing seat was causing a significant portion of the pressure drop. In order to address this issue he modeled the new valve with a larger opening below the solenoid poppet and removed the angled valve seat. The CFD simulation showed that this change substantially reduced the pressure drop to 1.09 psi. But it was still too high. Further changes to the design reduced the pressure drop across the valve to an acceptable 0.71 psi.
"We had complete confidence in the simulation results because FloEFD had provided such an accurate simulation of the original design," Preble concluded. "Without CFD, this knowledge would have been hard won. We would have had to go through a minimum of three prototypes, more likely several more. Each prototype would have cost $3000 and taken a month to manufacture, build and test. We took our simulation results to the customer and we were awarded the contract to build the valve. We are so confident that the new configuration will work we are not planning on building any prototypes. This application provides an excellent example of how the new generation of easy to use CFD software is helping to dramatically improve the design process at small and medium manufacturers with products that involve fluid flow."
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