Navy researchers look to rotating detonation engines to power the future
05 November 2012
US Naval Research Laboratory scientists are studying the physics of Rotating Detonation Engines, which offer the potential of reduced fuel consumption in gas-turbine engines.
NRL researchers have constructed a model of a Rotating Detonation Engine (photo: US Naval Research Laboratory)
The Navy depends on gas-turbine engines to provide propulsion and electricity for many of its ships. Even as future ships move toward the model of an all-electric propulsion system, they will still need gas-turbine engines to produce electricity for the propulsion system and other critical systems.
Gas-turbine engines are an attractive option because they scale nicely to large powers, are relatively small and self-contained, and are relatively easy to maintain. The gas-turbine engines the Navy uses today are based on the Brayton thermodynamic cycle, where air is compressed and mixed with fuel, combusted at a constant pressure, and expanded to do work, generating electricity or for propulsion. To improve the performance of gas-turbine engines, researchers are looking beyond the Brayton cycle to explore alternative and possibly more innovative cycles.
US Naval Research Laboratory (NRL) researchers believe that one attractive possibility is to use the detonation cycle instead of the Brayton cycle for powering a gas-turbine. NRL has been leading this research for the last decade and has been a major player in developing Pulse Detonation Engines (PDEs).
NRL researchers estimate that retrofitting engines on existing Navy ships, like the USS Arleigh Burke pictured here, with rotating detonation technology could result in millions of dollars in savings a year (photo: US Navy/Tommy Lamkin)
The Rotating Detonation Engine (RDE) provides a different strategy for using the detonation cycle to obtain better fuel efficiency. NRL researchers have constructed a model for simulating RDEs using earlier work done on general detonations, as a foundation. They believe that RDEs have the potential to meet 10 percent increased power requirements as well as 25 percent reduction in fuel use for future Navy applications.
Currently there are about 430 gas turbine engines on 129 US Navy ships. These engines burn approximately 2 billion dollars worth of fuel each year. By retrofitting these engines with the rotating detonation technology, researchers estimate that the Navy could save approximately 300 to 400 million dollars a year.
Like PDEs, RDEs have the potential to be a disruptive technology that can significantly alter the fuel efficiency of ships and aircraft; however, there are several challenges that must be overcome before the benefits are realised. NRL scientists are now focusing their current research efforts on getting a better understanding of how the RDE works and the type of performance that can be actually realised in practice.