Combustion modes periodical transition in a hydrogen-fueled scramjet combustor with rear-wall-expansion cavity flameholder
| Autor: | Wang Taiyu, Mingbo Sun, Zhenguo Wang, Yixin Yang, Zun Cai, Guang-xin Li |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Jet (fluid)
Materials science Renewable Energy Sustainability and the Environment Isolator Flame structure Energy Engineering and Power Technology 02 engineering and technology Mechanics Wake 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Combustion 01 natural sciences 0104 chemical sciences Physics::Fluid Dynamics symbols.namesake Fuel Technology Mach number symbols Combustor Scramjet Physics::Chemical Physics 0210 nano-technology |
| Zdroj: | International Journal of Hydrogen Energy. 45:3209-3215 |
| ISSN: | 0360-3199 |
| DOI: | 10.1016/j.ijhydene.2019.11.118 |
| Popis: | Cavity-stabilized combustion modes periodical transition in a laboratory hydrogen-fueled scramjet combustor were captured by high speed imaging. Experiments were performed with an isolator entrance Mach number of 2.92, and a sonic transverse fuel jet upstream of the cavity was employed. The reproducibility of the results had been tested in several repeated experiments. It is observed that, under a fixed combustor entry flow parameters and fuel equivalence ratio, after the flame has been fully developed, the flame structure may periodically transform between two different combustion modes. Specifically, under a moderate equivalence ratio, the flame structure switches between the cavity shear-layer stabilized mode and the combined shear-layer/recirculation stabilized mode, which shows an apparent periodicity with a period of about 7.5 ms. The formation mechanism for this novel phenomena is analyzed and some suppositions are given. When increasing the equivalence ratio to a high level, the flame structure shows a quasi-periodic low-frequency oscillation and the combustion mode changes between the combined shear-layer/recirculation stabilized mode and the cavity-assisted jet wake stabilized mode. At last, the formation mechanism and characteristics of the combined shear-layer/recirculation stabilized mode are detailed analyzed. |
| Databáze: | OpenAIRE |
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