Mie Scattering with Silicon Oil Droplets in Combustion Field

Mie scattering technique with silicon oil droplets (MSOD) has been applied in a laminar premixed flame in a stagnation point flow. A 1.2W laser beam of 514.5 nm wavelength has been used as a light source, and fine silicon oil droplets (diameter <2 µm, boiling point =300°C) are added in the combustible mixture of propane with air. High-intensity Mie scattering from silicon oil droplets is observed in the upstream region of the flame zone. In the downstream region of the flame zone, very low-intensity Mie scattering is observed, though droplets are vaporized at the flame zone. It is confirmed that the low-intensity Mie scattering comes from solid particles (silicon dioxide, ⋯) made from vapor of the silicon oil droplets at the flame zone. The results also show that no difference of the flame location and the extinction has been observed in cases with and without silicon oil droplets.