Rotating detonation engine
A rotating detonation engine (RDE) is a proposed engine using a form of pressure gain combustion, where one or more detonations continuously travel around an annular channel. Although none are in production, computational simulations and experimental results have shown that the RDE has potential,[1] and there is wide interest and research into the concept.[2]
Theoretically, detonative combustion, (i.e. that which happens at speeds above the speeds of sound), is more efficient than the conventional deflagrative combustion by as much as 25%[3]. If this theoretical gain in efficiency can be realized, there would be a major fuel savings benefit.[4][5] Because the combustion is supersonic, it can also more efficiently provide thrust at speeds above the speed of sound.
The disadvantages of the RDE include instability and noise.
Concept
The basic concept of an RDE is a detonation wave that travels around an annulus, which is a circular channel. First, fuel and oxidizer are injected into the channel, normally through small holes or slits. Initially, a detonation must be initiated in the fuel/oxidizer mixture by use of some form of ignitor. After the engine is started, however, the detonation is self-sustaining. The passing detonation ignites the fuel/oxidizer mixture, which releases the energy necessary to sustain the detonation. The combustion products expand out of the channel and are also pushed out of the channel by the incoming fuel and oxidizer.[6]
Although the RDE's design is similar to the pulse detonation engine (PDE), one aspect that makes the RDE superior is the fact that the waves constantly cycle around the chamber, while the PDE requires the chambers to be purged after each pulse.[7]
Current development
Several organisations have been working on RDE design.
US Navy
The US Navy is pushing the development of this engine,[8] but there is no known time of completion. Researchers at the Naval Research Laboratory (NRL) have been showing particular interest in detonation engines, such as the RDE, because they realize these engines have the capability to reduce the fuel consumption in their heavy vehicles.[9][10] Several obstacles still remain to overcome in order to use the RDE in the field.[11] NRL researchers are currently focusing on getting a better understanding of how the RDE works.
Aerojet Rocketdyne
Since 2010, Aerojet Rocketdyne has conducted over 520 tests of multiple configurations of a rotating detonation engine.[12]
NASA
Researchers at NASA also play a part in the development of the RDE. Daniel Paxson, an accredited scientist at the Glenn Research Center, has used simulations in computational fluid dynamics (CFD) to assess the RDE's detonation frame of reference and compares the performance with the PDE.[13] He found that the results from his code of the RDE were shown to be in favor of those from a more complex code; thus, stating that the RDE can perform at least on the same level. Furthermore, he found that the performance of the RDE can be directly compared to the PDE as their performance were essentially the same.
Energomash
According to the Russian Vice Prime Minister Dmitry Rogozin,[14] in mid-January 2018 NPO Energomash company successfully completed the initial test phase of a 2-ton class liquid propelant RDE and plans to develop larger ones for use in space launch vehicles.
Other research
Other experiments have used numerical procedures to better understand the flow-field of the RDE.[15]
References
- ^ Lu, Frank; Braun, Eric (7 July 2014). "Rotating Detonation Wave Propulsion: Experimental Challenges, Modeling, and Engine Concepts". Journal of Propulsion and Power. 30 (5). The American Institute of Aeronautics and Astronautics: 1125–1142. doi:10.2514/1.B34802.
- ^ Wolanski, Piotr (2013). "Detonative Propulsion". Proceedings of the Combustion Institute. 34 (1): 125–158. doi:10.1016/j.proci.2012.10.005.
- ^ "В России испытали модель детонационного двигателя для ракет будущего". Российская газета. 2018-01-18. Retrieved 2018-02-10.
- ^ Cao, Huan; Wilson, Donald (14–17 July 2013). "Parametric Cycle Analysis of Continuous Rotating Detonation Ejector-Augmented Rocket Engine". 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference: AIAA 2013–3971. doi:10.2514/6.2013-3971. ISBN 978-1-62410-222-6.
- ^ Schwer, Douglas; Kailasanath, Kailas (25 September 2010). "Numerical Investigation of the Physics of Rotating Detonation Engines". Proceedings of the Combustion Institute. 33 (2). Elsevier, Inc.: 2195–2202. doi:10.1016/j.proci.2010.07.050.
- ^ Wolanski, Piotr (2013). "Detonative Propulsion". Proceedings of the Combustion Institute. 34 (1): 125–158. doi:10.1016/j.proci.2012.10.005.
- ^ "Pressure Gain Combustion Program Committee - Resources". AIAA Pressure Gain Combustion Program Committee. Retrieved 2016-12-30.
- ^ "How the Rotating Detonation Engine Works". HowStuffWorks. Retrieved 2015-11-09.
- ^ "US Navy developing rotating detonation engine". Physics Today. 2012-11-06. doi:10.1063/PT.5.026505. ISSN 0031-9228.
- ^ "How the Rotating Detonation Engine Works". HowStuffWorks. Retrieved 2015-10-21.
- ^ "Navy Researchers Look to Rotating Detonation Engines to Power the Future - U.S. Naval Research Laboratory". www.nrl.navy.mil. Retrieved 2015-11-09.
- ^ Claflin, Scott. "Recent Advances in Power Cycles Using Rotating Detonation Engines with Subcritical and Supercritical CO2" (PDF). Southwest Research Institute. Retrieved 20 March 2017.
- ^ "UCSB Full Bib - External Link". pegasus.library.ucsb.edu. Retrieved 2015-11-09.
- ^ Facebook post, in Russian
- ^ Schwer, Douglas; Kailasanath, Kailas (2011-01-01). "Numerical investigation of the physics of rotating-detonation-engines". Proceedings of the Combustion Institute. 33 (2): 2195–2202. doi:10.1016/j.proci.2010.07.050.