Radiation from flames and gases in a cold wall combustion chamber

Journal article, 1970

The calculation of heat transfer in furnaces is usually based on coarse approximations of temperature and emissivity in the combustion chamber. This paper suggests a method suitable for machine computation of the heat transfer from flames and gases to the walls of a furnace. A theoretical derivation of the basic equation is made and the simplifications necessary for execution of the calculation in acceptable time are discussed The patterns of temperature and flame. emissivity are described by means of simple functions, a mathematical model. Experiments were carried out in an experimental furnace of simple geometry using one oil-burner in order to check the accuracy of the theoretical assumptions. Mcasurements of flame and gas temperature, flame emissivity, wall heat flux and exterior measurements necessary for the heat balance of the furnace were done. The measurements of temperature and emissivity define the mathematical model. The heat transfer from flame and gases (including the contribution due to reflexion, non-cold surfaces and convection) was calculated at four different loads of the furnace and compared with the heat flux measurements. The difference between measured and calculated heat flux, due to errors of measurements and calculations, was less than about 15 per cent of the total heat flux.