Emmons problem

In combustion, Emmons problem describes the flame structure which develops inside the boundary layer, created by a flowing oxidizer stream on flat fuel (solid or liquid) surfaces.

The problem was first studied by Howard Wilson Emmons in 1956.

[1][2][3] The flame is of diffusion flame type because it separates fuel and oxygen by a flame sheet.

The corresponding problem in a quiescent oxidizer environment is known as Clarke–Riley diffusion flame.

Source:[4] Consider a semi-infinite fuel surface with leading edge located at

and let the free stream oxidizer velocity be

is the self-similar Howarth–Dorodnitsyn coordinate), the mass flux

is vertical velocity) in the vertical direction can be obtained where In deriving this, it is assumed that the density

describes the values far away from the fuel surface.

The main interest in combustion process is the fuel burning rate, which is obtained by evaluating