Updating the modern techniques of radiative heat transfer calculation within fuel furnaces and boilers

摘要

Various methods of radiative heat transfer calculations are tested, verified and compared for some applied examples concerning the thermal processes within the working space of boilers and furnaces: of discrete ordinates (DOM) differential approach, of multiple reflections, of similarity with the models of computer graphics, zone method, CFD modeling, stochastic tests with Monte Carlo (MC) procedures. The opportunities and accuracy of MC calculations have been estimated for combustion chambers in 0 (zero), 1-, 2- and 3D statement. The appropriate radiation models for combustion products have been considered with special attention paid to the model of emissivity of selective (non-grey) gases computed as weighted sum of grey gases (WSGG) mostly compatible with the MC approach. Due provision the detailed and accurate information on temperature profiles within the volume zones both the thermal state and pollutants formation (particularly of NO) within the combustion chambers could be predicted being fairly coincided with measured data.