Designing and developing systems with rotating components often requires analysis and understanding the behavior of those components to improve performance. Computational Fluid Dynamics (CFD) software, such as SOLIDWORKS Flow Simulation, is a perfect tool for studying rotating components. It helps eliminate expensive physical prototypes, as well as finding improvements much earlier in the design process.
In previous versions, SOLIDWORKS Flow Simulation only used single and multiple rotating reference frame approaches to solve rotating flow problems. This method was a great way to analyze rotating components; however, this would only allow users to setup systems that flow in a steady-state manner. The term “steady-state” refers to a solution that does not vary with time.
Single Rotating Reference Frame, which assumes that the entire fluid domain/region rotates with the rotor/impeller, can be used to study the flow around the impeller blades, but does not take into account the boundary of the flow. For example, when analyzing a flow through a pump, a single rotating reference frame does not consider any effects of the pump casing on the flow and this is insufficient for analyzing a full pump system.
Using the Multiple Rotating Reference Frame, zero revolutions per minute (RPM) is assigned to non-rotating components, called stators, and fixed RPMs to the rotating components, called rotors. With this method, users can consider more than one rotor, each rotating with a different RPM. This method gives the user more insight to the full system but, again, it can only be solved using a steady-state approach.
With the all new Rotating mesh, also known as Sliding mesh method, flow studies can be solved in a transient approach. Essentially, the unsteady solution repeats with a period related to the speeds of the moving domains. Using the “sliding mesh” mode, SOLIDWORKS SIMULATION FLOW is able to simulate rotating equipment where fluid flow entering the rotor is highly non-symmetric with regard to the axis of rotation.
This is especially useful for rotating flow problems that require a time accurate solution for computing unsteady flow fields. Using this feature, the user is able to set the velocity and RPM properties of the rotating components, which will allow fluid driving motion with enhanced rotating regions to be simulated. Additionally, since angular velocities are dependent on time; motion flows with specified angles can also be simulated, as well as rotor speeds that are dependent on time.
From a results standpoint, everything is calculated on a time based scale. So when a user shows a cut plot, for example, they would be able to clearly see how the rotating components specifically effect the flow of the system. Furthermore, ISO surfaces and flow trajectories can then be plotted and clearly show how the flow is being “sucked” in, rotated around and blown out of a system.
To see this air flow rotation live in action and catch other exciting new enhancements in SOLIDWORKS 2015, be sure to attend a CADimensions Rollout event, coming to a town near you!
