Chemistry:Heat release parameter
From HandWiki
In combustion, heat release parameter (or gas expansion parameter) is a dimensionless parameter which measures the amount of heat released by the combustion process.[1][2] It is defined as
- [math]\displaystyle{ \alpha = \frac{T_b-T_u}{T_b} }[/math]
where
- [math]\displaystyle{ T_b }[/math] is the burnt gas temperature
- [math]\displaystyle{ T_u }[/math] is the unburnt mixture temperature.
In typical combustion process, [math]\displaystyle{ \alpha\approx 0.7-0.9 }[/math]. For isobaric combustion, using ideal gas law, the parameter can be expressed in terms of density,[3] i.e.,
- [math]\displaystyle{ \alpha = \frac{T_b-T_u}{T_b} = \frac{\rho_u-\rho_b}{\rho_u}. }[/math]
The ratio of burnt gas to unburnt gas temperature is
- [math]\displaystyle{ \frac{T_b}{T_u} = \frac{\rho_u}{\rho_b}=\frac{1}{1-\alpha}. }[/math]
See also
References
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