The 20 Twenties: Aaron Blacker

A perfect advisor pairing produced a "really cool" research opportunity for graduate student Aaron Blacker, one of three AAE students selected as "Tomorrow's Leaders: The 20 Twenties" by Aviation Week Network, in collaboration with the American Institute of Aeronautics and Astronautics (AIAA).
Aaron Blacker, a master's student in AAE, was selected as one of the "20 Twenties."

Aaron Blacker has Boilermaker blood, though that isn’t exactly why he is a master’s student in Purdue’s School of Aeronautics and Astronautics right now.

Grandfather Richard Mayoras, who played football at Purdue and graduated in the early 1960s with a degree in civil engineering, actually had little influence. Blacker chose Georgia Tech for his undergraduate studies following high school in New York.

But then Blacker was enticed by Maurice J. Zucrow Laboratories and captivated by the idea of working with William Anderson, a professor in AAE. So he chose Purdue to pursue a master’s degree.

And Mayoras was ecstatic.

“As a kid, I always remember he had so much Purdue memorabilia in his personal office. He loved talking about how he was able to balance engineering and Big Ten football. So the fact I was coming here was very exciting to him,” says Blacker, who had yearly visits over Christmas breaks at his grandfather’s and grandmother’s home in West Lafayette until he was 11. “He loves Purdue.”

Blacker can understand the passion now.

His daily work with Anderson performing research that studies lifted flames in a traverse-unstable rocket engine combustor has been rewarding and exciting.

And also has been recently recognized.

Blacker was one of three Purdue students selected as “Tomorrow’s Leaders: The 20 Twenties” by Aviation Week Network, in collaboration with the American Institute of Aeronautics and Astronautics (AIAA). Blacker will attend the 20 Twenties Awards Luncheon, in which he’ll be recognized as an award winner, and Aviation Week’s 62nd Annual Laureates Awards on March 14 at the National Building Museum in Washington D.C.

Blacker is eager to attend the event over spring break — he’ll be joined by his parents and girlfriend — and he hopes it provides an opportunity to speak more about his unique research.

Research, he says, that could only be done using data from Zucrow Labs. Which is precisely why he came to Purdue.

Blacker spent the summer after his junior year as an intern at SpaceX, and he quickly learned a large proportion of the propulsion engineers there had done research at Zucrow. So Blacker visited Purdue and Zucrow in Fall 2016 and met with Professors Anderson, Timothee Pourpoint and Steven Son.

“I was just really excited about Anderson’s work. He seemed to be a pretty big expert,” Blacker says. “I’d actually had a book with his name on it. So I figured it was the right place to be.”

And Zucrow, he knew, was ideal.

“If I really did want to be a propulsion engineer, I knew this was the place to go. It’s the foremost place to go to do rocket propulsion research,” Blacker says. “Zucrow allows students to get hands-on experience, which is crucial. At SpaceX, it’s difficult to complete projects without having ever touched hardware. You can understand as much physics as you want, but if you don’t have the skills that Zucrow provides — the building, designing, making things actually work — with a direct application to rocket propulsion, then it is very difficult to do the job there. They know that. That’s why they hire Zucrow students. Graduates get in and there’s not as much of a learning curve. And they can be contributive in new, creative ways that weren’t already there.”

Initially, while still a senior at Georgia Tech, Blacker worked with Anderson to develop a proposal for a National Science Foundation Graduate Research Fellowship Program, which Blacker was awarded. In his first year at Purdue, Blacker mainly helped out with hardware and testing at Zucrow, but, in his second year, he shifted topics after a conversation with Anderson.

Data from a previous experiment at Zucrow showed flames in a liquid rocket engine combustion were not positioned in a location that maximized combustion efficiency and stability, which is in the injector recess. Instead, they were stabilizing later, in the middle of the combustion chamber.

Anderson mentioned the results to Blacker and told him no one knew precisely why the flames responded in such a way — or if flames in real orbital rocket engines were behaving similarly. Blacker was intrigued by the problem and ready to take on the challenge of solving it.

“To be in Anderson’s group here enabled me to have the access to that knowledge,” Blacker says. “That conversation can happen in very few places in the world other than in Anderson’s office.”

Typically, one can’t see flames in a liquid rocket engine because it is in a metal encasement. But at Zucrow, students put quartz windows in the side of the combustion chamber to record chemiluminescence data that tracks heat release from the combustion process. The assumption is the flame position is directly implied by the heat release.

Blacker’s research is to understand why some flames are behaving differently than designed. The ultimate goal for his research — and whatever projects follow — is to develop a non-visual indicator of lifted flames. That way, a method could be developed to look at a “real” rocket engine and know if there are flames that are misbehaving. The more that’s understood about misbehaving flames, the more could be done to enhance the performance and stability of the rocket engine.

Blacker says there have been studies on lifted turbulent jet flames, but he isn’t aware of lifted flames being studied in a rocket engine, nor is it known if they’ve ever been documented to be seen in a rocket engine at all.

“We want the flames to be anchored to the rocket injector,” he says. “That’s where the fuel and the oxygen mix and burning can occur most efficiently. Lifted flames in rocket engines are bad, in theory. That’s what we’re trying to solve.”

Blacker’s research also is unique because these lifted flames aren’t observed in just any academic rocket engine but one with nine injector elements. Multi-element rocket engines more closely resemble orbit-class rocket engines. As a result, the fact that lifted flames exist in this combustor could have implications for the space-launch industry. Only Zucrow offers the rare opportunity to study these engines.

Typically, most of the rocket engine combustors fired at Zucrow are single-element. There is a single hole from which fuel and oxidizer enter the combustion chamber. In a multi-element rocket engine, there are often hundreds. For his research, Blacker has been able to use data from a nine-element engine at Zucrow.

“Even if someone had this optical data of lifted flames in a single-element rocket engine, it would be very interesting. But this is even closer to what actually might happen in the real thing,” he says.

Blacker’s research doesn’t require him to touch hardware. He mostly works on a computer, analyzing point-wise and 2D spatiotemporal measurements. Ideally, he’s hoping to throw out the 2D measurements and discern if the flames are acting strangely with just the measurements that exist on real rocket engines, which are the pressure measurements.

“It’s a pretty cool project,” Blacker says.

More on AAE's 20 Twenties: Alexis Harroun, Adam Patel