CFD Analysis of Centrifugal Blood Pump | Simulation in Healthcare

In the development of a ventricular assist device, computational fluid dynamics (CFD) analysis has become an effective method to acquire the best design before making the final prototype.

CFD Evaluation in Medical Device Design Validation

The core objective of computational fluid dynam­ics (CFD) analysis is to acquire pertinent information about the device performance and functionality, before making a final prototype.

In addition, it can help to attain an efficient hydrodynamic perfor­mance for corresponding devices by alternating the geometry of the inlet diameter of this pump, and performing the numerical simulation in order to choose the design that is best suited.

What’s more, CFD evaluation is used not only to achieve the best hydrodynamic performance, but also to anticipate adverse factors, such as regions and situations of thrombus formation and blood damage.




How is CFD Analysis Utilized in Healthcare?

A three-dimensional (3-D) CFD geometry model for analysis’ on medical devices can be generated using a 3-D computer aided design (CAD) software package such as Ansys Workbench Mechanical.

For context, the computational domain contains the inlet, the magnetically pendulous rotor, the gaps which distinguish the rotor from the stationary housing wall, as well as the outlet.

In common simulations done here at SimuTech Group, an unstructured CFD mesh can be generated in a grid generating software (Ansys Fluent) with an exhaustive mesh comprised of ~600,000 tetrahedral cells.









CFD Simulation | Achieving a Time-Accurate Solution

Computational fluid dynamics (CFD) analysis can then be formed with an unstructured mesh finite volume­ based CFD package, such as Fluent, in order to achieve a time-accurate solution for rotor­ stator interaction.

Subsequently, the domain would likely be divided into moving and stationary subdomains, while the sliding mesh model can be used to compute unsteady interactions within the model.

From here, the coupling of the rotating domain and the stationary domains can be achieved through proper arrangement of the mesh model.

You’ll notice (if done correctly) the interface zones of adjacent cell zones are associated with one another to form a grid interface. The two cell zones will move analogous to each other along the grids structural interface.

For each isolated time sequence, the meshes are moved, while the fluxes at sliding interfaces are recalculated and analyzed.

The time-step size should be set to perform an entire rotational period of the corresponding rotor, and the accompanied number (____k) of uniform increments.

CFD Analysis | Importance of Discussing Results with Production Manager

I hope we have presented the power of merging engineering simulation software in modern industries such as healthcare.  As demonstrated (hopefully), computation fluid dynamics (CFD) analysis is an efficient way obtain the best design before making the final prototype of a centrifugal blood pump, along with other medical devices.

In short, these problems can be evaluated by CFD analysis in terms of exposure time of the blood cell, the shear stress applied, confined acceleration, and place of blood recirculation.






Utility of CFD Analysis | Investigating Pump Flow Characteristics

Whether evaluating different inlet diameters of the pump to investigate the flow characteristics and performance, or simulating the design to the actual, on-hand equipment available at the manufacturing facility, CFD is the best way to approach the question of design.

For flow pattern in two different instants of time, within the initial stage of the development of a centrifugal blood pump, for example, may reveal that adoption an impeller with a straight radial blade model may be more feasible, as is rather simple to manufacture a prototype.

These are common instances where engineers need to be in close contact with operations and the Production Manager.  This nuance of materials available, coupled with internal decision-making and discussion during the CFD analysis, is what is crucial for businesses to understand.