Source: University of Washington
It takes a lot of fuel to launch something into space. Sending NASA’s Space Shuttle into orbit required more than 3.5 million pounds of fuel, which is about 15 times heavier than a blue whale.
But a new type of engine called a rotating detonation engine promises to make rockets. Not only more fuel-efficient but also more lightweight and less complicated to construct. There’s just one problem: Right now this engine is too unpredictable to be used in an actual rocket.
“The rotating detonation engine field is still in its infancy. We have tons of data about these engines, but we don’t understand. What is going on,” said lead author James Koch, a UW doctoral student in aeronautics and astronautics. “I tried to recast our results by looking at pattern formations instead of asking an engineering question such as how to get the highest performing engine and then boom, it turned out that it works.”
“A rotating detonation engine takes a different approach to how it combusts propellant,” Koch said. “It’s made of concentric cylinders. Propellant flows in the gap between the cylinders, and, after ignition. The rapid heat release forms a shock wave, a strong pulse of gas with significantly higher pressure and temperature. That is moving faster than the speed of sound.
“This is the only model in the literature currently capable of describing the diverse and complex dynamics of these rotating detonation engines. That we observe in experiments,” said co-author J. Nathan Kutz, a UW professor of applied mathematics.
The model allowed the researchers to determine for the first time whether an engine of this type would be stable or unstable. It also allowed them to assess how well a specific engine was performing.
“This new approach is different from conventional wisdom in the field. And its broad applications and new insights were a complete surprise to me.”Said co-author Carl Knowlen, a UW research associate professor in aeronautics and astronautics.