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- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 45449 (45)
- University: Sharif University of Technology
- Department: Aerospace Engineering
- Advisor(s): Farshchi, Mohammad
- Abstract:
- Inlet flow of afterburners comes from the burnt products of the primary combustion chamber. The fuel is injected and the mixture is ignited to form a flame which is stabilized behind a flameholder in the afterburner. Flame stability stems from wake (recirculation zone) of flameholder. With the aid of high residence time of flow behind the flameholder reactants get the time to catch activation energy. Some parameters like oxygen content, mass flow rate, inlet temperature, and nozzle area ratio play an important role in afterburner combustion efficiency and flame stability. In this study we focused on afterburner combustion stability in GE J85-21 engine. This engine will be in service through 2040. The J85 offers the highest thrust-to-weight ratio of any production engine in its class. The present numerical study focuses on concepts of flame stability in an afterburner system and its sensitivity analyses. For this purpose the j85-21 afterburner is modeled and numerically analyzed. The afterburner model comprises of four main regions; diffuser, flameholder, chamber, nozzle, and plume. First and foremost, in this study the best equivalence ratio ranges for optimizing combustion efficiency and a stable flame in every flow condition have been specified. Besides, experimental dry (16kN) and wet (22kN) thrust under some distinct flow condition have been reached
- Keywords:
- Reheating ; Combustion Stability ; J 85 Engine ; Flame Stability Criteria ; Flame Holder