Mil Tech — Vulcan Engine Revs Up
Jan 04 2010
Say the word “Vulcan” and many people immediately think of Mr. Spock, the pointy-eared human-Vulcan on the Star Trek television series and films. But for the Defense Advanced Research Projects Agency (DARPA), Vulcan is a far different matter.
Vulcan is a propulsion system program to design, build, and ground test an engine capable of accelerating a full-scale hypersonic vehicle from rest to Mach 4+.
The Vulcan will be a constant volume combustion (CVC) engine and a full-scale turbine. Contractors working on the first phase of the engine development — Alliant TechSystems, General Electric, Rolls Royce, and United Technologies — will be able to choose from CVC engine architectures such as pulsed detonation engines (PDEs), continuous detonation engines (CDEs), or other CVC engine architectures.
Contractors will use a current production turbine engine capable of operating above Mach 2, such as the F-100–229, the F-110–129, the F-119. or the F-414 engine.
Contrasted with traditional propulsion engines that burn fuel in a constant pressure manner, a CVC engine uses a combustion cycle based on combusting fuel in a constant volume manner. Such engine cycles, DARPA thinks, offer the potential for very significant performance improvements over conventional cycles and have the ability to operate statically through high Mach numbers and offer significant design flexibility.
But because CVC cycles typically are unsteady and incorporate multiple combustors and unique valving, several technical challenges have to be overcome.
These include developing low total pressure loss detonation initiation devices, low total pressure loss air valves, thermal management systems, efficient nozzles, and control systems, among others. However, DARPA believes recent advances will give the program a strong foundation.
A key program objective is to integrate the turbine engine into the Vulcan engine system with minimal modification to the turbine and to operate the turbine from rest to its upper Mach limit, and then cocoon it when not in use during flight. The CVC and turbine engines will share a common inlet and nozzle.
The Vulcan engine is expected to propel vehicles that could be used for payload transport, reconnaissance, or strike missions.
About the author: Alan M. Petrillo is a Tucson, Ariz., freelance writer who works in a wide variety of fields, writing for national and regional magazines and newspapers. He’s also the author of the mystery novel, Full Moon, and several books on historical military small arms.
