[29.] Liu, K., Burluka, A.A., and Sheppard, C.G.W., "Turbulent Flame and

Mass Burning Rate in a Spark Ignition Engine," Fuel 107:202-208, 2013, doi:10.1016/j.fueL2013.01.042.

The two main contributions to the reduction in the in-cylinder conditions (P,T) upon increasing the water fraction in air are changes in mass burning rate (primarily the laminar burning velocity, see eq.1 and 2, [34]) and thermophysical properties (primarily the heat capacity) of the fuel-air mixture.

Both the reduction in mass burning rate and the increase in heat capacity with increasing water fraction in air reduce the peak pressure and temperature as shown in Fig.6.

However, the

mass burning rate of TEA (0.029 kg/[m.sup.2]-s) is much slower than short chain hydrocarbon fuels such as hexane (0.077 kg/[m.sup.2]-s) and isopentane (0.103 kg/[m.sup.2]-s) [11].

In the above, [m.sub.a] and [[LAMBDA].sub.0] are, respectively, the

mass burning rate and the

mass burning rate eigenvalue in the adiabatic condition.

Mass burning rate is calculated by following equation.

The specific

mass burning rate (rate of mass loss per unit area) was calculated from the surface regression rate and the density of the oil.

Mass, composition (equivalence ratio), temperature and

mass burning rate are calculated for every individual spray packet (zone).

To solve the governing equations given above we need to find an expression for the

mass burning rate ([dm.sub.b]/dt) that takes into account the operating conditions (e.g.

The difference [m.sub.e] - [m.sub.b] is the mass in the flame brush, Increasing flame brush and the fresh gas density means that this difference should grow during the flame propagation at a constant turbulent

mass burning rate, contrary to Eq.

where the

mass burning rate [dm.sub.b]/dt is achieved from pressure data, the flame area [A.sub.f] is determined over the burnt volume by assuming spherical flame shape and [[rho].sub.u] is the density of the unburnt zone.

The

mass burning rate in a homogeneous SI engine can be defined as,