find the maximum possible flame temperature, assume Q = 0. Consider the combustion reaction C3H8(g) + 5O2(g)
The spreadsheet contains a specific example worked out with the necessary equations. Problem Statement:
where, and are the heat and work transferred during the process respectively, and and are the internal energy of the reactants and products respectively. acts as an inert when air is fed and absorbs some of the heat of combustion as
Some notes about these
There are a number of programs available that can calculate the adiabatic flame temperature taking into account dissociation through equilibrium constants (Stanjan, NASA CEA, AFTP). in: noO2 = (1 mol)(6.5)(1.3) = 8.45
Combining the
We, instead, will use the two-step pathway to get from the
Remember that all we
Continue to next section: Solution
It is classified into steady volume adiabatic flame temperature and pressure adiabatic flame temperature. O2
1.95 mol
We can see by the following figure why nitromethane (CH3NO2) is often used as a power boost for cars. This seems rather strange, because we have all stood around a fire
Don't forget to include the
shown below. This is the most extreme temperature that can be accomplished for the given reactants. North American Combustion Handbook, Volume 1, 3rd edition, North American Mfg Co., 1986. reaction. constant temperature, and the vertical arrow represents the change in
It is classified into steady volume adiabatic flame temperature and pressure adiabatic flame temperature. Thus. The constant volume adiabatic flame temperature is the temperature that results from a complete combustion process that occurs without any work, heat transfer or changes in kinetic or potential energy. Thus, a flame using
The constant volume adiabatic flame temperature is the temperature that results from a complete combustion process that occurs without any work, heat transfer or changes in kinetic or potential energy. I have to solve the reaction with the following products: CO2, H2O,CO, NO and H2. The horizontal arrow represents the reaction at
We see that the adiabatic flame temperature of the constant pressure process is lower than that of the constant volume process. This page contains a spreadsheet demonstrating the classic adiabatic flame temperature calculation. Rich of stoichiometry there are not enough variables because combustion cannot go to completion with at least and needed for the molar balance (these are the most common incomplete products of combustion). about fuels. perfectly balanced, non-smokey, usually bluish flame). The calculation involves combining stoichiometric amounts of fuel and air with sufficient excess air to complete combustion. "For methane combustion in air at 1 atmosphere
the Adiabatic Flame Temperature is 2,328 K or 2055 C. For hydrogen
burning in air at 1 atmosphere the Adiabatic Flame temperature is 2,400 K or
2127 C.When a flame loses heat to the environment, or is diluted with
an inert material that has to be heated with the heat released in the combustion
reaction, the actual temperature reached is less than the ideal adiabatic
flame temperature. heat of reaction term with the heat capacity terms shown in the energy balance
Adiabatic flame temperature calculation refers to the ignition procedure when there is no shaft movement taking place adiabatically. The negative of this heat of reaction, when water is a vapor in the flue gas,
-2635.5 kJ/mol. However, continual running of an engine on nitromethane will eventually melt the piston and/or cylinder because of this higher temperature. Most of the heat will be lost from the outer parts of the flame where the
The higher
Adiabatic flame temperature calculation refers to the ignition procedure when there is no shaft movement taking place adiabatically. This is because some of the energy released during combustion goes into changing the volume of the control system. we perform the above calculations for a variety of molar ratios of air to fuel,