Research Of Modelling Of Reheating Furnace Based On Gaseous Radiation

Mathematical modelling of thermal process is meaningful for the process control of reheating furnaces. The initial purpose of this dissertation is to improve the accuracy of calculating the thermal exchange in furnace chambers, and to support the decision and scheduling of the furnace operation, by means of calculating the heat flow of slab in furnaces and decreasing the error of temperature field of the slab.The production in combustion, e.g. gas is the heat source, playing an important role in the process of heat exchange in furnace chambers. Research of its gaseous radiation is basic to study the heat exchange in furnace chamber. In this dissertation, the coupling between mean beam length Le and absorption coefficient ka is deduced. By iterating Leckner series and inversion of direct exchange area Le, an algorithm is presented to solve ka and Le together. The principle of ka and Le with respect to temperature is conducted on basis of this solution. Moreover, since there is no solitary ratio for furnaces with Fuel supply by blast furnace, coke oven, converter gas under the assumption of a calorific value, the effects of the varieties of this ratio on ka and Le are also examined.An algorithm of calculating mean beam length with only grid on the surface is also presented on the aspect of the integral of direct exchange area to decrease the calculation burden.The algorithm of calculating total radiant exchange area for the ternary system model with imaginary planes is improved. Overcome calculation difficulty when exist blackbody surface.The equation for hot junction of thermocouple and imaginary plane is derived, in order to calculate Furnace temperatures.All the procedure lays a foundation for dynamic compensation of ka and amend total heat exchange factor.