Rotating Detonation Engine Fundamental Physics Investigation
Abstract
Over the contract period from December 2017 to December 2022, we have explored the fundamental operating characteristics of RDREs with methane-oxygen propellant in test rigs having combustor diameters of 6 feet, 3 feet, 2 feet, 1 feet and 0.394 feet (10 mm). Injectors with staggered radial jets and axial impinging jets were utilized with various annular gap widths and core lengths. In all configurations, stable RDRE operation was established within a broad envelope of equivalence ratio and propellant mass flux. A key finding was that the back pressure of experiments would alter the combustor wave dynamics and even suppress RDRE operation if the mass flux was too low. Thus, the RDRE test rigs must be operated at a mass flux greater than the critical value for a given back pressure in order to examine the dependence of combustor dynamics on just fueling conditions and geometry. In the geometrically scaled test rigs (3, 2, 1), the wave dynamics depended primarily on the mass flux and equivalence ratio. At constant equivalence ratio, the transition to operation with one more wave was found to occur at the same mass flux in these three RDREs. This resulted in 3, 2, and 1 waves in the 3, 2 and 1 RDREs, respectively. At constant mass flux, operating conditions with this same wave number sequence were established under both fuel lean and rich test conditions. The gap width variations explored in the 1 RDRE included a coreless configuration, which exhibited spin speeds when fuel lean that exceeded CJ speeds calculated at STP conditions. The coreless configuration of the 0.394 RDRE had a smaller envelope of operation. It exhibited a single spinning wave at the same mass flux as the larger RDREs in the equivalence ratio range of 1.1 to 1.4. As far as we know, this is the smallest operable RDRE yet demonstrated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 26, 2023
- Accession Number
- AD1230629
Entities
People
- Knowlen Carl
Organizations
- University of Washington