The key advantage of a TEA based system over currently used single-function engine start techniques is that it provides multi-faceted benefits over other cold start systems such as intense energy release, readily ignitable ethane gas, atomization of the fuel through effervescence, and pyrophoricity for ignition. As such, it likely has utility to assist in not only the cold-start of scramjets but the re-light of turbojets with minimal modifications. If developed for such an approach, the TEA based system would be capable of providing engine start functionality for both the turbojet and scramjet in a turbine-based combined-cycle vehicle, significantly reducing overall system complexity. Companies such as Pratt & Whitney Rocketdyne that develop both turbojets and scramjets would find such a capable and simplifying system to be of great benefit in meeting the system requirements of a combined-cycle hypersonic vehicle. The DoD is interested in developing these types of vehicles as well as scramjet powered missile systems to gain a hypersonic strike capability to stay ahead of competing foreign entities. In addition the system may find use in the high altitude relight of turbine engines in fighter and UAV applications. A dilute TEA-based scramjet cold start system is expected to have significant mass and volume savings compared to equivalent and more traditional scramjet cold start techniques such as silane and ethylene when compared on an equivalence ratio basis. These mass and volume savings translate directly into additional capability and can alleviate some of the system packaging requirements of future hypersonic vehicle systems. Safety is also enhanced over the more traditional high pressure gaseous systems by using low pressure, non-pyrophoric, liquid reactants. It is only upon mixing the dilute TEA/JP with water that heat , ethane, and pyrophoric TEA are released. In addition, the potential low Mach capability of a TEA based system helps extend the utility of scramjet engines proposed for turbine-based combined cycle hypersonic vehicles to lower Mach numbers, providing flexibility in selecting high-speed turbines capable of generating the required Mach number for scramjet takeover. NASA is interested in these types of vehicles as potential solutions for cheaper, reusable, more effective access to space.
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