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Apparent heat release model
 The first work in this direction derived from the first law of thermodynamics
was proposed in Krieger and Borman [1967] and was called the computation of
apparent heat release.
 The method takes neither heat transfer nor crevice effects into account, thus
dQht is lumped into dQ = dQch − dQht and dmc = dmi =0
 The apparent heat release dQ can be expressed as:
 This model is the same Rassweiler-Withrow model, assuming that γ(T) = n
 The difference between two modal are:
Rassweiler-Withrow model:
Apparent heat release model
Apparent heat release model:
 So:
 Results:
Apparent heat release model
Apparent heat release model:
 So:
 Results:
Solid: Apparent heat
release model
Dash-dotted: R&W
model
Apparent heat release model
 The net heat release trace and mass fraction burned profile from the Krieger and
Borman model are similar to those from the Rassweiler-Withrow method, the first
being physically the more accurate one.
 For this particular case, the Rassweiler-Withrow method yields a higher burn
rate compared to the apparent heat release method for the same data.
 This is also reflected in the heat release trace, and the difference is due to the
assumptions on n and Vj+1/2 in the Rassweiler-Withrow method. The mass fraction
burned profile is calculated assuming that the mass of burned mixture is
proportional to the amount of released chemical energy.