Soot formation in a jet-stirred combustor

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6149491

Hodges, J T

Soot mass concentration, average soot particle size, incipient soot limit (ISL) and gas temperature were measured in a premixed Jet Stirred Combustor (JSC) fueled by toluene and air. The purpose of the measurements was to quantify the kinetics of soot growth in a turbulent backmixed combustion environment. At a given stoichiometry, the maximum burned gas temperature increased by approximately 300{degree}C as the mass flowrate was increased from 0.75 - 3.0 g/s. The ISL increased with flowrate. At a flowrate of 2.1 g/s, the ISL reached a maximum and decreased as the flowrate was increased up to 3.0 g/s. For stoichiometries richer than the ISL, soot mass concentration was measured via extinction of laser light. The net rate of soot production was found to be very flowrate dependent and was minimized at a flowrate of 2.1 g/s. Below, 2.1 g/s, the temperature dependence of the sooting tendency was in accord with trends observed in laminar premixed flames. Average particle size and number density were measured via laser scattering and extinction. A kinetic model of soot nucleation, coagulation and surface growth (applicable to homogeneous steady flow systems) was developed. In conjunction with the size and concentration data it was inferred that the soot nucleation rate was on the order of 1013 particles/cm{sup 3}s. The specific rate of surface growth was estimated to be of the order 10{sup {minus}4} g/(cm{sup 2}s). In comparison with laminar flame data, the soot nucleation rate in the JSC was found to be nearly 2 orders of magnitude less, whereas the surface growth rate was of the same magnitude. It was postulated that soot nucleation was suppressed due to the presence of relatively high OH concentrations which exist in the JSC due to backmixing of the products of combustion with reactants.

• Research Organization: Wisconsin Univ., Madison, WI (USA)
• OSTI ID: 6149491
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
SOOT
SYNTHESIS
TOLUENE
COMBUSTION KINETICS
AGGLOMERATION
AIR
COMBUSTION PRODUCTS
COMBUSTORS
CORRELATIONS
FLAMES
FLOW RATE
GAS FLOW
HYDROXIDES
INHIBITION
LAMINAR FLOW
LASERS
LIGHT SCATTERING
LIMITING VALUES
MATHEMATICAL MODELS
MEASURING METHODS
MIXING
NUCLEATION
PARTICLE SIZE
QUANTITY RATIO
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TEMPERATURE MEASUREMENT
TURBULENT FLOW
ALKYLATED AROMATICS
AROMATICS
CHEMICAL REACTION KINETICS
FLUID FLOW
FLUIDS
GASES
HYDROCARBONS
HYDROGEN COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
REACTION KINETICS
SCATTERING
SIZE
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry