A Florida team that has been working with the US Air Force says that it has created and tested an experimental model of an engine. Why is it such a big deal? That’s because it claims that it is a rotating detonation rocket engine that relies on spinning explosions within a ring channel for creating a highly efficient thrust. The team hails from the University of Central Florida and worked in collaboration with the Air Force Research Laboratory to create the Rotating Detonation Rocket Engine Program.
Detonation can release much more energy with lesser fuel as opposed to the conventional combustion engines. Rocket scientists have been working on this idea for over 60 years. Such a device would begin with one cylinder inside a bigger one and shall feature a gap between them along with small holes through which the fuel for detonation could be pushed. It was pioneered by engineers in the 1950s at the University of Michigan.
The Rotating Detonation Rocket Engine Program is a 3-inch copper test ring that relies on a mix of hydrogen and oxygen as fuel. This particular fuel is the highest-performing rocket fuel for the upper stage rocket engines. Kareem Ahmed who is an assistant professor in UCF’s Department of Mechanical and Aerospace Engineering and led the research said, ‘The study presents, for the first time, experimental evidence of a safe and functioning hydrogen and oxygen propellant detonation in a rotating detonation rocket engine. The detonation is sustained continuously until you cut off the fuel. We have tested up to 200 lbf, but the thrust increases linearly with the propellant mass flow.’
Ahmed further said, ‘We have to tune the sizes of the jets releasing the propellants to enhance the mixing for a local hydrogen-oxygen mixture. So, when the rotating explosion comes by for this fresh mixture, it’s still sustained. Because if you have your composition mixture slightly off, it will tend to deflagrate, or burn slowly instead of detonating. Just a few months prior, a number of US rocket engine experts had publicly declared that hydrogen-oxygen detonation engines were not possible. However, the paper presents experimental evidence and demonstrated without a doubt that detonation of oxygen and hydrogen are occurring within a rotating detonation rocket engine.’
On the other hand, William Hargus who is the lead at the Air Force Research Laboratory’s Rotation Detonation Rocket Engine Program said, ‘These research results already are having repercussions across the international research community. Several projects are now re-examining hydrogen detonation combustion within rotating detonation rocket engines because of these results. I am very proud to be associated with this high-quality research.’
The US Air Force intends to have a rocket launch flight test conducted by 2025. The team’s results have been published in the journal Combustion and Flame.