**Superscripts**

278 Mass Transfer in Chemical Engineering Processes

measure of the thermal energy in the reaction zone relative to the activation energy

boundary-layer variable normal to the surface or perturbed concentration

thermal conductivity or parameter defined in the ignition analysis

*u* velocity component along *x*

*v* velocity component along *y*

*x* tangential distance along the surface

stoichiometric CO2-to-reactant mass ratio

 perturbed temperature in the outer region perturbed temperature in the inner region

A water vapor or C-H2O surface reaction a critical value at flame attachment

O oxygen or C-O2 surface reaction

freestream or ambience

P carbon dioxide or C-CO2 surface reaction

*y* normal distance from the surface

 conventional transfer number temperature gradient at the surface reduced gas-phase Damköhler number product(CO2)-to-carbon mass ratio

stoichiometric coefficient

*V* freestream velocity

*W* molecular weight *w* reaction rate

*Y* mass fraction

**Greek symbols** 

viscosity

 density inner variable streamfunction reaction rate

**Subscripts** 

C carbon

N nitrogen

s surface

out outer region

F carbon monoxide *f* flame sheet g gas phase ig ignition in inner region max maximum value

profile function

