Fundamentals of Soot Formation in Gas Turbine Combustors
Abstract
An experimental facility for studying soot formation in high temperature, fuel-rich, laminar, premixed flames has been constructed. Diagnostics included laser absorption, thermocouple particle densitometry, and thermophoretic soot sampling with analysis by transmission electron microscopy. Single particles with diameters as small as 3-5 nanometers were observed. Larger particles (20-25 nanometers) agglomerated to form large clusters. A coflow, axisymmetric, laminar ethylene diffusion flame has been studied, both experimentally and computationally. A lifted flame has been selected to eliminate possible uncertainties caused by the burner lip. A two-dimensional, detailed soot growth model in which the equations for particle production are coupled to the flow and gaseous species conservation equations has been used to investigate soot production in the flame. Detailed transport and finite rate chemistry in the gas phase was coupled with the particle aerosol equations in the sectional representation. In comparison to measured data obtained using intrusive and non- intrusive diagnostics, the model predicted temperature, flame height, and major species very well. Peak benzene concentrations and soot volume fraction were predicted to within 20% of the experimental value. The predicted distribution of benzene was excellent, but the soot was underpredicted along the centerline. This deficit was attributed to limitations in the PAH growth model. Oxidation of particulates was dominated by reactions with hydroxyl radical at superequilibrium levels. Radiation losses significantly effected predicted temperatures.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1998
- Accession Number
- ADA353430
Entities
People
- David S. Liscinsky
- Meredith B. Colket Iii.
- Mitchell D. Smooke
- Robert J. Hall
Organizations
- United Technologies Corporation