Uniform TitleResidence-time-fixed investigation of pressure and temperature effects on the flame synthesis of nanoparticles
NameSmith, Megan E. (author), Tse, Stephen (chair), Lin, Hao (internal member), Prakash, Shaurya (internal member), Rutgers University, Graduate School - New Brunswick,
SubjectMechanical and Aerospace Engineering,
DescriptionThe synthesis of nano-titania (n-TiO2) is investigated experimentally and computationally in low-pressure H2/O2/inert(s) burner-stabilized flat flames with strategic helium/argon/nitrogen dilution in a stagnation point geometry, using a metal-organic (titanium tetra-isopropoxide, TTIP) precursor. Gas-phase simulation is applied to compute various experimental flame structures. The employment of combinations of different molecular weight and specific heat capacity inert gases makes it possible to tailor the flame structure, so as to isolate various known parameters affecting particle growth, while maintaining fixed gas-phase residence time. Using this method, the effects of ambient pressure and temperature are studied. Two particle growth and evolution sub-models (i.e. a monodisperse model and a sectional model), which utilize the gas-phase modeling results, calculate the primary and aggregate particle sizes as a function of axial location in the flow field. After deposition on a cooled substrate, the powders are characterized ex-situ using X-ray diffraction (XRD) and Brunaur-Emmet-Teller (BET) measurements to determine nanopowder characteristics, such as phase/crystallinity and specific surface area (from which primary particle size can be inferred). This study indicates that pressure, with other parameters fixed, has limited effect on particle growth. With identical temperature histories at 20, 30, and 40torr, the primary particle sizes vary by less than 1nm, computationally, and less than 0.8nm experimentally. In contrast, temperature, with other parameters fixed, plays a significant role in primary particle development. Particles generated in strategically diluted flames, with only an 80K difference in maximum temperature, have primary sizes that are more than 2.5nm different.
NoteIncludes bibliographical references (p. 83).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.