Brian Mitchell is a lab manager responsible for the development of computational fluid dynamics (CFD) codes and methods that are used heavily by GE Aviation, GE Power & Water, and GE Oil & Gas for the design of turbomachinery, e.g. jet engines, gas turbines, etc.
I had the chance to talk with Brian to provide you with a bit more insight on the below image, beyond its visual appeal. At the bottom of the post, I’ve also shared an animation, so be sure to check that out as well. See my Q&A with Brian below and feel free to ask questions in the comment box regarding the visual and the work we are doing in CFD.
This image is hypnotizing. What are we seeing and how does it help GE?
What we are visualizing is the unsteady flow through the low pressure turbine (LPT) of a jet aircraft engine. The flow field is fundamentally unsteady due to the unsteady geometry, i.e. the blades are alternatingly rotating or stationary, but historically our computational technology was limited to steady flow. By computing the unsteadiness, we get a better understanding of aerodynamics loss which we can utilized to design more efficient products.
We used an in-house code called TACOMA to run this simulation – tell us about how it came to be and what advantages we have thanks to our solver?
GE has been utilizing CFD for the development of our turbomachinery products for 30 years. As computer power has increased, the complexity of the problems we want to simulate increases and this requires continuous attention and development of the CFD solver. In order to push the state-of-the-art in the space of turbomachinery, we have found value in having close control of our software, and so we decided many years ago to write our own CFD solver. TACOMA is our latest code and it has been in use for over a decade.
What other numerical tools are used in the design of turbomachinery?
A code like TACOMA is part of an ecosystem of software that address the need to create geometry, meshes, and to visualize the results. While much attention gets paid to the results of unsteady 3D analysis, we also rely on 1D and 2D tools as well. These lower order tools are very useful during the preliminary design phase when geometry is still being laid out.
How do we make sure a computer model gives us a good result compared to a physical test?
Validation is an important topic that cannot be ignored when utilizing simulations. GE has a variety of physical data from rig tests and full engine tests. We routinely compare our simulations back to our data to make sure we understand their accuracy.
What advantages are there to virtual engineering test over physical tests?
Simulations and physical tests are both important and both have a role in the design process. Simulations are much faster to run (compared to building test hardware) and give more data than testing. This makes simulations well suited for optimizing a design and for digging into flow physics. Physical tests are important to validate the design and to ensure we understand the accuracy of the simulations.
The Discovery Channel shared a short video featuring John Hengeveld, the marketing director for High Performance Computing (HPC) at Intel discussing how computation can play a role in curing diseases. I recommend checking it out to better understand HPC’s role in science, engineering and medicine!