# 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 industrial method.  Acquire the best design before making the final prototype.

### CFD Evaluation in Medical Device Design Validation

In short, the core objective of computational fluid dynam­ics (CFD) analysis is to acquire pertinent information about the device performance and functionality.  In terms of process, this should be prior making a physical prototype.

In fact, early-stage CFD evaluation can help to attain an efficient hydrodynamic perfor­mance for corresponding devices.  Particularly, by alternating the geometry of the inlet diameter of this pump, and performing numerical simulations.  This will benefit material selection and the determine optimal design specifications.

Additionally, CFD evaluation is used not only to achieve the best hydrodynamic performance, but also to anticipate adverse factors.  This includes bodily-region and situational analysis 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 for detailed model visualization.  This is achieved by using a 3-D computer aided design (CAD) software package such as Ansys Workbench Mechanical.

For context, the computational domain contains the inlet, and the magnetically pendulous rotor.  Added to the equation, include 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). This consists of 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, with FDA compliance, 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

Considering evaluating different inlet diameters of the pump to investigate the flow characteristics and performance, or simulating the design to the actual?  For 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: Specifically, within the initial stage of the development of a centrifugal blood pump, may reveal, for example, that adoption an impeller with a straight radial blade model may be more feasible.  As it is, operating procedure and expenses are a consideration as well as simplicity of manufacturing a prototype.

Clearly, 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.