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Full-Text Articles in Engineering
Characterization For Spray Droplet Behaviour In Afterburner-Like Flow Conditions, Matthew D. Mahaffy
Characterization For Spray Droplet Behaviour In Afterburner-Like Flow Conditions, Matthew D. Mahaffy
Electronic Thesis and Dissertation Repository
Fuel injection processes can contribute to combustion instability in highly energetic combustion systems. In gas turbine engine afterburners, jet-in-crossflow (JIX) injection is used. Part one of the thesis study investigates the interaction between spray droplets and turbulent flow properties of a JIX. Jet-in-counterflow (JIC) configuration was also investigated. Part two of the investigation examined the behaviour of JIX droplets around a bluff body. Droplet size and flow turbulence was characterized simultaneously using particle image velocimetry and image processing techniques. Turbulence and droplet size were correlated, particularly at momentum flux ratios ≥ 60. High speed imaging was used to identify droplet …
An Experimental Investigation Of Self-Excited Combustion Dynamics In A Single Element Lean Direct Injection (Ldi) Combustor, Rohan M. Gejji
An Experimental Investigation Of Self-Excited Combustion Dynamics In A Single Element Lean Direct Injection (Ldi) Combustor, Rohan M. Gejji
Open Access Dissertations
The management of combustion dynamics in gas turbine combustors has become more challenging as strict NOx/CO emission standards have led to engine operation in a narrow, lean regime. While premixed or partially premixed combustor configurations such as the Lean Premixed Pre-vaporized (LPP), Rich Quench Lean burn (RQL), and Lean Direct Injection (LDI) have shown a potential for reduced NOx emissions, they promote a coupling between acoustics, hydrodynamics and combustion that can lead to combustion instabilities. These couplings can be quite complex, and their detailed understanding is a pre-requisite to any engine development program and for the development of predictive capability …
Distinguishing Harmonic Behavior Of Longitudinal Resonant Combustion In A Variable Geometry Model Rocket Combustor, Sarah W. Hester
Distinguishing Harmonic Behavior Of Longitudinal Resonant Combustion In A Variable Geometry Model Rocket Combustor, Sarah W. Hester
Open Access Theses
Throughout the study of high frequency combustion instability in a single element Continuously Variable Resonance Combustor (CVRC), the excitation of the fundamental longitudinal mode is closely followed by the excitation of higher harmonic modes. In an attempt to establish a heuristic relationship between the appearances of the fundamental mode and its harmonics, several unstable fixed geometry and variable geometry tests from the CVRC are analyzed through traditional Fourier-based methods and alternative signal processing methods such as wavelet analysis and Instantaneous Frequency (IF) Analysis from PC Signal Analysis. Early results led to the conclusion that traditional Fourier-based analysis provides believable and …