ARNOLD AIR FORCE BASE, Tenn. – This August, 14 test analysts and test engineers supporting the 717th Test Squadron, part of the 804th Test Group at Arnold Engineering Development Complex, headquartered at Arnold Air Force Base, participated in a training opportunity.

The 804 TG Analysis and Technology Development Branch, or TDA, had expressed a desire for AEDC analysts to become more proficient with incorporating modeling and simulations, or M&S, into their daily workflow. M&S offers turbine engine testers the ability to quickly perform design studies modeled using acquired test data. This quick turnaround provides engine program offices the analysis they need to make informed decisions for future appropriation of limited resources.

One tool increasingly common across the aerospace industry is digital simulation, sometimes referred to as “digital twin.” A digital twin is just that: a digital representation of a real-world device or physics-based process. When done correctly, the digital twin may offer predictive insight into the performance of a test article.

Numerical Propulsion System Simulation, or NPSS, is a software architecture developed by the NASA Glenn Research Center in the 1990s. It was later turned over to a consortium of turbine engine manufacturers. This software allows engineers to model complex thermodynamic processes and is used in all phases of testing. Before the test is executed, modeling predicts results and investigates potential adverse test cell/test article interactions. During test execution, models aid data validation and data quality control. After the test execution phase, models are critical in analysis of the test data and the data validates the model.

In 2013, the consortium of manufacturers chose the Southwest Research Institute, or SwRI, to manage NPSS on their behalf. Leadership from the Technical Management and Advisory Services contract at Arnold AFB reached out to SwRI to arrange for onsite training of AEDC personnel at the University of Tennessee Space Institute.

For four days, students were given a basic-intermediate level education regarding the software’s setup, use and common modifications. Students also participated in trade studies that demonstrated the software’s ability to rapidly provide results for off-design performance.

“Each module of the course consisted of a presentation followed by an exercise where we were able to put the principles to use while receiving feedback,” said Erin Sanders, AEDC test analyst. “As a whole, I found the course also helped expand my coding skills in different languages, something that I have found to be a bit lacking from my undergraduate curriculum. One of the features I found most fascinating was how a visual representation is built as one writes applicable elements of the code. I look forward to working with my colleagues to apply NPSS on future projects.”

Stephen Arnold, 717 TS technical adviser, said the test contractor quickly coordinated this training opportunity.

“We will continue to be forward looking so that we can ensure the American warfighter has a distinct advantage,” Arnold said.

The ability to utilize this robust architecture will not only aid the 717 TS test analysts but will also aid the 804 TG in integrating propulsion and aerodynamic modeling capabilities. The ability to model the whole system is a step in understanding the total system performance as well as the uncertainty and risks associated with the weapon system.

“Having the test analysts integrated within the modeling capabilities will greatly increase the value to the test group,” said Mike Wrenn, 804 TG TDA technical advisor. “I appreciate the 717th’s shared desire to leverage this capability and build proficiency in the turbine M&S capability.”