Week 8: July 31 - August 4
This week, I not only had the opportunity to watch lab members collect 4D MRI data, but I was also able to assist them in compiling data on the computer. This enabled me to get a better sense of the software side of the CVFD lab's work. Such experience was valuable to me because I am highly interested in computers. Even if the work I engaged in was unique to the CVFD lab, I was told that many of the programs and processes were common in both mechanical engineering and engineering in general.
On a sadder note, Friday was Luis' and Armando's last day, as they headed back to Puerto Rico on Saturday. Nonetheless, I am very happy that I was able to meet them through this opportunity. In addition, it's exciting to think that in the future I might be able to participate in an engineering program that takes me to a lab in a completely different setting like theirs did.
Computational Fluid Dynamics
In addition to conducting hands-on tests, such as 4D MRI and PIV, the CVFD lab also uses Computational Fluid Dynamics (CFD) to simulate the tests beforehand. While their application is centered around blood flow through the body, CFD has a multitude of other applications, such as plumbing systems and machine engines. I was able to watch others model the patient-specific TCPCs, simulate flow through them, and collect data. The process was highly complicated. One lab member explained that, after receiving numerous parameters, such as the inlet/outlet velocities or whether the flow is turbulent or laminar, the computer rapidly performs a very large number of calculations at each point in the provided model to determine what the flow would look like. The result is highly accurate data that can also be used to create beautiful 3D diagrams of the flow.
4D MRI
On Monday this week, I had the opportunity of watching the lab collect 4D MRI data on some of the patient-specific TCPC models. While it was really interesting, because the hospital has MR specialists to run the scanner, the CVFD members only needed to hook a model up to the perfusion pump and lay it on the MR bed.
Working with Ensight
Ensight is a program that can accept various different types of fluid data, including CFD, PIV, and 4D MRI, to model fluid flow and calculate values for various variables. I used Ensight to to model both 4D MRI data of the TCPC models and CFD data from Liver models.
Both processes involved creating inlet/outlet planes on the models rendered from the data for the flow to run through. After this, streamlines could be drawn based on the data. These streamlines could be altered to show the flow rates at different points in the model and could also indicate trends in the direction of flow based on their density. On top of this, the streamlines could be animated to show a simulation of flow through the model over a span of time.
For the TCPC models, I was tasked with taking screenshots of each model with streamlines to indicate the flow rate. For the Liver models, I was tasked with recording the calculated minimum and maximum kinetic energy, helicity, and vorticity for each model, along with counting the streamline densities of the outlet flow.
