Improving the Flammability and Flameholding Characteristics of Solid Fuel Ramjets
Abstract
The purpose of the proposed research is to provide a fundamental understanding on the effects of injector design, fuel grain design, and fuel supplements on performance characteristics of solid fuel ramjets (SFRJs). Due to the flow characteristics in the combustor, SFRJs typically require a rearward facing step at the injector/combustor interface which limits the volumetricfuel loading of the propulsion system. This ultimately limits the overall performance of the flight vehicle. The proposed research will specifically study fuel regression rates, combustion efficiency, and flameholding characteristics over a range of air to fuel ratios and combustor inlet air temperatures with the goal of improving the volumetric fuel loading in a practical SFRJ.In order to evaluate these parameters, two primary experiments will be used. The first experiment is a lab scale counterflow diffusion flame burner, which will allow for the determination of flame structure, ignition requirements, and regression rates of fuels. This lab scale experiment will also provide useful information to help evaluate flammability andflameholding characteristics. It is expected that the counterflow diffusion flame burner experiments will continue through the duration of the effort as new fuel supplements will be evaluated as they become available.The second experiment is a static fired direct connect solid fuel ramjet. Flight Mach numbers between 2 and 3.5 will be simulated. Within this experiment three primary variables will be evaluated for their effect on fuel regression rates, combustion efficiency, andflameholding characteristics. First, the effects of injector geometry will be studied on a baseline fuel. Second, novel fuel grain designs will be considered based on previous hybrid rocket work.Lastly, the addition of fuel supplements will be evaluated for their effectiveness in improvingflameholding. We will specifically study materials that have high hydrogen content (eg. Metal hydrides) looking to take advantage of the greater flammability limits of hydrogen in comparison to hydrocarbons. Combinations of these variables will also be explored in an attempt to optimize combustor performance. When this research is completed, it is anticipated that significantimprovements to SFRJ technology will be made resulting in significant improvements in range for missiles and projectiles.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 29, 2020
- Source ID
- N000142012316
Entities
People
- Gregory Young
Organizations
- Office of Naval Research
- United States Navy
- Virginia Tech