Entropy Analysis of the Process of Burning of a Gas in the Furnace of a Water-Tube Boiler with a Secondary Radiator.

An analytical study has been made of the operating processes of burning of natural gas in the furnace of a steam water-tube boiler. The authors have determined the fields of the combustion-product temperature and of the heat-flux density in the furnace volume, and also the thermodynamic parameters of the reaction of combustion of methane and the enthalpy and entropy change of combustion products in the furnace with a secondary radiator and without it. The distribution of the entropy fields has been given and the regions of high entropy production near heat-transfer surfaces during the heat exchange of combustion products have been determined. To obtain optimum results, the authors used the model of minimum entropy generation in the thermodynamic system. An exergy analysis has been made of the operating processes of the chemical reactions of combustion and heat exchange of the combustion products with the tubular surfaces of the steam boiler. The influence of structural and regime parameters of the boiler furnace on the exergy loss has been shown. [ABSTRACT FROM AUTHOR]