Lean Operation of a Pulse Detonation Combustor by Fuel Stratification
| Autor: | Niclas Hanraths, Neda Djordjevic, Fabian Habicht, Christian Oliver Paschereit, Fatma Cansu Yücel |
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| Rok vydání: | 2021 |
| Předmět: |
Gas turbines
Thermal efficiency Materials science 010304 chemical physics Mechanical Engineering Nuclear engineering Detonation Energy Engineering and Power Technology Aerospace Engineering Stratification (water) 010402 general chemistry Combustion 01 natural sciences 0104 chemical sciences Pulse (physics) Fuel Technology Nuclear Energy and Engineering 0103 physical sciences Combustor Combustion chamber |
| Zdroj: | Journal of Engineering for Gas Turbines and Power. 143 |
| ISSN: | 1528-8919 0742-4795 |
| DOI: | 10.1115/1.4048775 |
| Popis: | Pressure gain combustion is a promising concept to substantially increase the thermal efficiency of gas turbines. One possible implementation that has been frequently investigated are pulse detonation combustors (PDCs), as they permit stable and reliable operation. At the same time, the need for part-load operation and low NOx emissions requires combustion concepts in the lean regime. However, realizing lean combustion is still very challenging in PDCs since the deflagration to detonation transition (DDT) is very sensitive to the reactant composition. The present work investigates an approach to realize lean combustion in PDC by applying fuel stratification experimentally. The scope is to find the necessary increase of fuel concentration inside the pre-detonation chamber to provide reliable DDT with respect to the overall equivalence ratio. Emission measurements in the exhaust of the PDC allow for a quantification of the NOx emissions as a function of the injected fuel profile. A valveless PDC test rig is used, which contains a shock focusing geometry for detonation initiation and is ignited by a spark plug close to the upstream end wall. The subsequent expansion of the burned gas and interaction of the flame front with turbulence leads to the formation of a leading shock inside the pre-detonation chamber, which is then focused inside a converging-diverging geometry. The successful initiation of a detonation wave by shock focusing is very sensitive to the pressure ratio across the leading shock, which can be influenced by initial pressure, reactant composition and flow velocity. Results reveal that fuel stratification allows for reliable detonation initiation at a global equivalence ratio of ϕglob = 0.65, whereas repeatable successful operation with non-stratified fuel injection is limited to ϕglob ≥ 0.85. |
| Databáze: | OpenAIRE |
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