The Capabilities and Limitations of Flow Simulation

One of the grey areas of Simulation swirl around the SolidWorks Flow Simulation product-line, where the capabilities and limitations are critical to ensure successful implementation. Earlier this week, we had a potential customer inquire into the functional capabilities of Flow Simulation.

Flow Simulation is an excellent mid-range fluid flow product if you are trying to simulate anything from liquids to gas flow. It can be utilized in a wide range of applications from electronics to valves to HVAC to medical and automotive/aerospace applications, and also  where fluid flow coupled with thermal analysis is a requirement.

Below is a compiled list of the capabilities and limitations of the SOLIDWORKS Flow Simulation productline as of 2009:

What Flow Simulation can do

• Incompressible (liquid or gas) or compressible (gas) viscous flow including subsonic, transonic and supersonic regimes
• External and/or internal flows
• Non-Newtonian Flows (Viscous fluids such as blood)
• Automatic laminar/turbulent solution with transition
• Wall roughness model
• Swirling flows and fans (fan curves)
• One component or up to ten independent species -liquid-liquid mixing, or gas-gas mixing
• Forced, free or mixed convection – heat transfer
• Conjugated heat transfer (fluid, solid), conduction and convection
• Porous Media
• Radiation
• Steady state and Transient (time-dependent) fluid flow
• Rotating Frames of Reference
• TEC coolers/heat sink emulators/Thermostats
• Cavitation
• Relative Humidity

What Flow Simulation cannot do

• Phase Change – The Flow package cannot handle materials cooling and transforming from gas-to-liquid, or molten liquid-to-solid. Similarly, it cannot handle materials heating from molten solid-to-liquid, or liquid-to-gas. This requires special high-end non-linear and complex formulations specifically for modeling entropy and chemical/molecular changes to account for cool down etc. Eg: plastic flow throw an injection mold as it cools and solidifies.
• Co-existence of different phases – Flow Simulation cannot simulate a liquid and a gas in the same cavity. For instance, water flowing out of a nozzle into air (since water and air exist in the same cavity after the water flows out). Similarly, sprays (where fluid bubbles are sprayed into air). Different fluids (liquids/gases) can co-exist in a Flow Simulation if they exist in different cavities or volumes.
• Free Surface Phenomena – Flow Simulation cannot simulate the top layer of a liquid sitting in an open tank. This again requires highly non-linear and complex formulae that are characteristic of high-end packages.
• Moving bodies – Flow Simulation cannot simulate bodies moving and displacing fluids as they move. This requires special high-end focused packages that can handle Fluid-Structure-Interaction (FSI).
• Combustion – Flow Simulation cannot perform chemical reactions to account for combustion.
• Particles/Suspensions – Flow Simulation cannot simulate solid/liquid suspensions in a fluid where the suspensions can influence the pattern/parameters of flow. Since Flow Simulation cannot have two different phases in the same volume, it does not support solid particles in a fluid stream/liquid particles in a fluid stream/gas trapped in a liquid stream etc.