Application of CFD technology in Research and Development
In this article, I show you a wide variety of CFD applications in Research and Development and will take a closer look at the use of CFD in bioengineering. In the end, I will demonstrate a short example of a simulation of blood flow in an artery performed using QuickerSim CFDToolbox.
Application of CFD often saves time and cuts costs. It allows us to reduce the number of physical prototypes, gain insight into physical phenomena that is difficult to observe directly from the experiment or predict key process parameters from any location in the region of interest. When most of us hear “CFD”, we immediately think about flow in pipes and valves, rotating machinery, electronics cooling or flow around the aircraft. Although CFD is mainly used in fields of mechanical and chemical engineering, its popularity grows in other areas of scientific research.
One of the crucial areas of development for CFD is bioengineering. With the ever-evolving CFD solvers, it can solve more and more complex problems, such as the systems of the human body. Such simulations can give a huge opportunity to improve the existing medical devices and investigate new design ideas.
Cardiovascular diseases are the leading cause of death worldwide, according to the WHO report [1]. The most common coronary artery disease treatment is a stent. It is a metal or plastic tube inserted into the lumen of an anatomic vessel or duct to hold open passages. In the open literature [2-4], we can find many studies on using CFD techniques to develop safer and more effective stents. CFD is used to simulate the flow of blood through the artery and predict the wall shear rate in the vessel. Further research might enable to create the unique stents and provide an individual approach to each patient.
Another area in which CFD has a lot of potentials is diabetes treatment. It is a metabolic disease in which the pancreas is unable to regulate the levels of blood glucose. Currently, the researchers work on a device called a bionic pancreas, that could automatically monitor blood glucose levels and deliver insulin or glucagon when needed. Application of CFD might help with verifying if the average time of the flow of a given blood portion is sufficient for proper hormones distribution. It is also necessary to check whether there are any turbulence or too slow flow where there would be a risk of blood clotting.
The last example concerns the COVID-19 pandemic that has affected us all. Can CFD help to fight against this problem? The answer is yes. The scientific community uses technology to study the mechanism of the airborne dispersion of particles ejected due to different respiratory mechanisms, create respiratory equipment for treatment or even aid vaccine production. Designing unique respiratory devices is particularly important because each patient has a different lung structure and breathing profile. Thanks to CFD, it is possible to create patient-specific respiratory masks with all individual details in a shorter processing time without making many expensive prototypes.
Example Simulation of the pulsatile flow of blood through the bifurcated carotid artery
In this case, I want to present the simulation case of an unsteady flow of blood. The arterial geometry was obtained thanks to the 3D reconstruction method. In the next step, I generate a computational grid that consists of 116 264 tetrahedral cells. The sinusoidal velocity profile is specified at the inlet. Figure 1 shows the geometry of the carotid artery and defined boundary conditions at the proper faces.
For the purpose of this showcase, blood is assumed to be a Newtonian fluid. In Figure 2 I present the obtained shear rate results in the analyzed vessel for the maximum velocity. Maximum shear rate occurs on the junction and near the inlet and the outlets. I observe high values of shear rate at the inlet and the outlets, which are some numerical artefacts. Since the most interesting part for us is the junction, we can omit those points from the outlets and inlets because they do not carry any physical meaning in this area.
Conclusion
In this article, I have presented the possibilities of using CFD in Research and Development. I have focused on bioengineering to show that CFD can also solve more complex problems, and with further development, it might be a powerful tool that helps to save lives. In the end, I have given an example of a blood flow simulation using our QuickerSim CFDToolbox.