The burning of a fuel particle in an oxidizing atmosphere

A variety of phenomena are exhibited by the burning of a spherical fuel particle in an infinite oxidizing atmosphere. Here we shall consider one of the simplest situations, the quasisteady, spherically symmetrical burning of a liquid fuel that vaporizes and reacts in a gas-phase flame, producing gaseous products that flow and diffuse to infinity. However, at the outset it is of interest to indicate some of the complexities that may arise in other situations. Because of the diversity of high-temperature oxidation mec-anisms of solids [24], [46], these complexities often are associated with the burning of solid fuels. 

An industrial atmosphere is characterized by pollution composed mainly of sulfur compoimds such as sulfur dioxide (SO ), a precursor to acid rain, and nitrogen oxides (NO ), the backbone of smog in modern dties. Sulfur dioxide from burning coal or other fossil fuels is picked up by moisture on dust particles as sulfurous add. This is oxidized by some catalytic process on the dust particles to sulfuric acid, which settles in microscopic droplets and fall as acid rain on exposed surfaces. The result is that contaminants in an industrial atmosphere, plus dew or fog, produce a highly corrosive, wet, acid film on exposed surfaces. 

A mixture of ammonium perchlorate (AP NH4CIO4) and a hydrocarbon polymer (BDR) used as fuel binder forms an AP pyrolant that generates white smoke when it burns in a humid atmosphere. The polymer acts as a binder of the AP particles to form a rubber-like material. When the AP pyrolant burns, the AP particles oxidize the hydrocarbon polymer according to ... 

---