Fluid Flow Simulation of Pneumatic Components

CFD has become an integral part in the development of pneumatic components at Festo. In the last couple of years, applications have included internal flows in valves, air supply components and vacuum ejector systems, and flows in and around sound absorbers.

The small dimensions of pneumatic components make detailed experimental measurements expensive and in some cases, simply impossible. CFD therefore plays a vital role in the pre-development phase as the only possible way to understand the influence of geometrical variations.

For its CFD requirements, Festo chose AEA Technology’s CFX-TASCflow to analyse and improve the operation of these components and to investigate innovative products. Experimental validation of the predicted forces on existing designs confirms the accuracy of CFX-TASCflow for simulating highly-compressible, turbulent flow conditions. At the same time, the fully-coupled multigrid solver ensures fast convergence and robustness.

Generally, optimisation of pneumatic valves requires maximisation of the flow rate in combination with minimisation of the flow forces. Many design increments can be investigated quickly with CFX-TASCflow, and experimental testing limited to the final optimised design.

Another major application where CFD is used extensively is in the design of Festo’s porous sound absorbers for pneumatically-driven automation systems. From experience, the greater the flow speed and velocity gradients around the sound absorber, the higher the expected sound level. Using CFX-TASCflow’s porous model option, Festo can identify designs which avoid these conditions and therefore ensure maximum flow rate with satisfactory sound levels.

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