Park, Seul-Hyun
Choi, Mun Young
Yozgatlıgil, Ahmet
The nanostructure of soot particles collected from spherically symmetric ethanol droplet flames were analyzed using a high resolution transmission electron microscopy (HRTEM). Nanostructure properties, including fringe length and curvature of carbon lamellae, were measured for soot particles collected in various inert environments. The sampling experiments were performed in the reduced gravity environments produced in the NASA 2.2 sec Droptower at the Glenn Research Center in Cleveland, Ohio. Microgravity droplet combustion experiments provide unique opportunities to vary the residence times over a large range and to independently vary the temperature. In this study, the time-temperature histories experienced by the soot particles were adjusted by means of inert substitutions (argon vs. helium) and variations in the initial droplet diameters (ranging from 1.6 to 2.2 mm). The variations in the initial droplet diameter were found to affect only the residence time necessary for soot inception and growth, whereas inert substitutions modified both residence time and temperature. The measurements of soot nanostructure properties indicated that the higher temperatures produced in the argon inert environment produced more graphitic nanostructures, while the lower temperatures produced in the helium inert environment produced more amorphous nanostructures at the inner core of the soot primary particle. The variations in the initial droplet diameter produced distinct soot nanostructures on the periphery of the soot particle. The higher residence times experienced for the largest initial droplet diameter experiments produced longer carbon lamellae with negligible curvature, while the lower residence times for the smallest initial droplet diameter experiments produced shorter carbon lamellae with higher degrees of curvature. These experimental results provide important foundational understanding of the influence of residence time and temperature on the soot nanostructure that has not been studied previously.


New observations of isolated ethanol droplet flames in microgravity conditions
Park, Seul-Hyun; Choi, Seuk-Cheun; Choi, Mun Young; Yozgatlıgil, Ahmet (Informa UK Limited, 2008-01-01)
Spherically symmetric ethanol droplet combustion experiments were performed to investigate the influence of initial droplet diameter, ambient pressure and inert substitution on the burning and sooting behaviors of ethanol droplet flames. Experiments were performed using the 2.2 sec reduced-gravity droptower facilities at the NASA Glenn Research Center. Noting the importance of transport characteristics of heat and species and their attendant effects on flame temperature and residence time on the sooting mec...
HUAI, HY; GAINES, AF; FLINT, CD (Elsevier BV, 1992-11-01)
Scanning electron microscopy of particles of three bituminous coals (78.5% C, 81.7% C and 89.9% C d.a.f.) which had been treated with pyridine, methanol, bromine, air, sulfuric acid, ammonia and alkylating agents showed that the reagents produced significant changes in the morphology of the particles. The particles cracked and disintegrated in ways which appear to be characteristic of the disruption of hydrogen bonding, the volume and thermal changes accompanying local reactions and of the breakage of C-C b...
Analytical investigation of wet combustion process for heavy oil recovery
Bağcı, Ali Suat (Informa UK Limited, 2004-12-01)
Analysis of combustion tube data produced from experiments performed under realistic reservoir conditions is currently the most valid method of investigating in-situ combustion process. In this study, the optimization of water-air ratio for B. Kozluca heavy crude oil, and the comparison of the performance of dry and wet forward combustion processes were studied. An analytical model was used to extend the laboratory results so that the oil production and steam zone volume can be estimated under field conditi...
Characterization of BPN Pyrotechnic Composition Containing Micro- and Nanometer-Sized Boron Particles
Koc, Suzan; Ulaş, Abdullah; Yilmaz, Nil Ezgi (Wiley, 2015-10-01)
The effect of micro- and nanometer-sized boron particles on boron-potassium nitrate (BPN) ignition composition was investigated in this paper. As a starting point, thermochemical calculations were made to determine the most promising ignition compositions. Both stoichiometric and fuel-rich formulations of BPN were produced to observe the performance variation due to boron content. Particle morphology of boron particles and the surface structure of the ignition compositions were investigated by SEM. The infl...
A study on the effects of catalysts on pyrolysis and combustion characteristics of Turkish lignite in oxy-fuel conditions
ABBASI-ATIBEH, Ehsan; Yozgatlıgil, Ahmet (Elsevier BV, 2014-01-01)
The catalytic pyrolysis and combustion characteristics of low calorific value Turkish lignite in various ambient conditions were explored and the evolution of gases during pyrolysis tests was examined using a Thermogravimetric Analyzer coupled with a Fourier Transform Infrared spectrometer (TGA-FTIR). Potassium carbonate (K2CO3), calcium hydroxide (Ca(OH)(2)) and iron (III) oxide (Fe2O3) were employed as precursors of the catalysts and compared to the Raw-form (no catalyst added) to investigate the effects ...
Citation Formats
S.-H. Park, M. Y. Choi, and A. Yozgatlıgil, “NANOSTRUCTURE OF SOOT COLLECTED FROM ETHANOL DROPLET FLAMES IN MICROGRAVITY,” COMBUSTION SCIENCE AND TECHNOLOGY, pp. 1164–1186, 2009, Accessed: 00, 2020. [Online]. Available: