Author: Edward G. Stricker
Publisher:
Published: 1950
Total Pages: 28
ISBN-13:
DOWNLOAD EBOOK →The combustion efficiency and the altitude operational limits of three liquid hydrocarbon fuels having high volumetric energy content (decalin, tetralin, and monomethylnaphthalene) were compared with an AN-F-58 fuel in a single tubular combustor from a J33 turbojet engine. The investigation covered a range of simulated engine conditions for altitudes from 20,000 to 60,000 feet; 42- to 107-percent normal rated engine speed; and a flight Mach number of 0.6. The independent effects of combustor-inlet-air temperature, pressure, and mass air flow on the combustion efficiency of the fuels were determined around a standard combustion-inlet condition.
Author: Ralph T. Dittrich
Publisher:
Published: 1948
Total Pages: 34
ISBN-13:
DOWNLOAD EBOOK →A study was made to determine the cause of irreproducibility of combustion data of a single tubular-type turbojet combustor operating at simulated altitude conditions.
Author:
Publisher:
Published: 2004
Total Pages:
ISBN-13:
DOWNLOAD EBOOK →To achieve single digit NOx emission from gas turbine combustors and prevent the combustion dynamics encountered in Lean Premixed Combustion, it is essential to understand the correlations among emission characteristics, combustion dynamics, and dynamics and characteristics of swirling flow field. The focus of this dissertation is to investigate the emission characteristics and combustion dynamics of multiple swirl dump combustors either in premixing or non-premixed combustion (e.g. Lean Direct Injection), and correlate these combustion characteristics (emissions, combustion instability and lean flammability) to the fluids dynamics (flow structures and its evolution). This study covers measurement of velocity flow field, temperature field, and combustion under effects of various parameters, including inlet flow Reynolds number, inlet air temperature, swirl configurations, downstream exhaust nozzle contraction ratios, length of mixing tube. These parameters are tested in both liquid and gaseous fuel combustions. Knowledge obtained through this comprehensive study is applied to passive and active controls for improving gas turbine combustion performance in the aid of novel sensor and actuator technologies. Emissions and combustion characteristics are shown closely related to the shape and size of central recirculation zone (CRZ), the mean and turbulence velocity and strain rate, and dynamics of large vortical structures. The passive controls, mostly geometry factors, affect the combustion characteristics and emissions through their influences on flow fields, and consequently temperature and radical fields. Air assist, which is used to adjust the momentum of fuel spray, is effective in reducing NOx and depress combustion oscillation without hurting LBO. Fuel distribution/split is also one important factor for achieving low NOx emission and control of combustion dynamics. The dynamics of combustion, including flame oscillations close to LBO and acoustic combustion instability, can be characterized by OH*/CH* radical oscillations and phase-locked chemiluminescence imaging. The periodic fluctuation of jet velocity and formation of large vortical structures within CRZ are responsible for combustion instability in multiple swirl combustors.