The knowledge about soot particle growth in diffusion flames strongly impacts the improvements of diesel engine emissions. Measuring the size and shape of soot particles enables the development of models about soot particle growth, agglomeration and oxidation.
Fundamentally formed particles are spherical and smaller than the wavelength of light (300 - 600 nm). During agglomeration processes these particles glue together to larger clusters. Hence, the simultaneous determination of both parameters, size and shape of the particles in a flame, is necessary for an exactly investigation of soot particle formation.
A combination of three techniques is described in this work to determine temperature, size and shape of the particles, formed in an acetylene-air-flame by a slit burner.
Two methods, the scattering / polarization ratio method for the size / optical constant measurement and the diffraction pitch method for the shape measurement, are developed under the use of particles of known refractive index and diameter for calibration measurements.