Heat release parameter

In combustion, heat release parameter (or gas expansion parameter) is a dimensionless parameter which measures the amount of heat released by an adibatic combustion process.Williams, Forman A. "Combustion theory." (1985).Linan, Amable, and Forman Arthur Williams. "Fundamental aspects of combustion." (1993). It is defined as

:$q\; =\; \backslash frac\{T\_\{ad\}-T\_u\}\{T\_u\}$

where

• $T\_\{ad\}$ is the adiabatic flame temperature
• $T\_u$ is the unburnt mixture temperature.

In typical combustion process, $q\backslash approx\; 2-7$. For isobaric combustion, using ideal gas law, the parameter can be expressed in terms of density,Clavin, P. (1985). Dynamic behavior of premixed flame fronts in laminar and turbulent flows. Progress in energy and combustion science, 11(1), 1-59. i.e.,

:$q\; =\; \backslash frac\{T\_\{ad\}-T\_u\}\{T\_u\}\; =\; \backslash frac\{\backslash rho\_u-\backslash rho\_\{ad\}\}\{\backslash rho\_u\}.$

The ratio of burnt gas to unburnt gas temperature is

:$\backslash frac\{T\_\{ad\}\}\{T\_u\}\; =1+q.$