Low Cost Hypermixing Ejector Ramjet Program.

Abstract : The Air Force Aerospace Research Laboratories (ARL) recently made a technology breakthrough in the field of turbulent mixing. ARL experiments indicated that the spreading rate of a subsonic jet may be increased dramatically by the introduction of streamwise vortices in the flow. These vortices promote efficient turbulent mixing within an extremely short distance, i.e., hypermixing. The basic objective of this program was to assess the payoff, if any, of applying hypermixing ejector technology to the design of a low cost ejecto ramjet engine. Three variations of the ejector ramjet engine cycle were evaluated at the engine design point of Mach 0.75 at 20000 feet altitude. The fuel addition-mix/diffuse/burn cycle variation was clearly superior. The selected fuel was UDMH. Engine performance was estimated for the specified flight envelope, Mo = 0.70 to 1.20 and sea level to 30000 feet altitude. An annular ring ejector which incorporated hypermixing technology was designed, fabricated, and experimentally evaluated.