Adiabatic Flame Temperature
This page contains a spreadsheet demonstrating the classic adiabatic flame temperature calculation. With combustion processes, it is often necessary to either achieve a specified combustion temperature or avoid exceeding a high temperature limit. The calculation involves combining stoichiometric amounts of fuel and air with sufficient excess air to complete combustion. The flame temperature depends on the heat capacity of the gases, which in turn are a function of temperature. To be exact, the heat capacity varies over the temperature range of the gases as they are heated.
The attached spreadsheet contains an example of such a calculation. The chemical equations for combustion are written out. A material balance is performed to obtain moles of each component before and after combustion. Mean molar heat capacity is developed by integrating over a polynomial form of a correlation between heat capacity and temperature. Finally, the temperature is calculated iteratively using the Excel goal seek function.
The spreadsheet contains a specific example worked out with the necessary equations. A second sheet contains a general form of the calculation. The user can select different compounds from a drop-down list and input the mole fraction of the fuel. The calculation occurs in a background VBA program.
