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Show H=lT Cp(1)dT TO (9) where Cp(T) is ~e specific heat at constant pressure defmed as a polynomial function of temperature. The enthalpy source tenns comprise the radiative heating Srad computed by RAD3D and the heat release of combustion Hflame determined by a modeling of flame. Density is defined from the ideal gas law: p·w p--- R·T (10) where W is the molecular weight, R is the universal gas constant, P is the pressure of atmosphere, and T is the temperature calculated from eqs.(5) and (9). Analytical Model of Furnaces Figs.4 and 5 show the analytical models of the reheating furnace and the forge furnace respectively. The reheating furnace is box-shaped with its inner dimension being 5500 x 2750 x 7000 tnm. The furnace heats in total 12 (3x4) slabs, each being 1400 x 1400 x 200 tnm, located 700 nun above the hearth. The reheating furnace shown in Fig.4(a) is equipped with four conventional nozzle-mixing burners, each two of which are installed along each of two furnace side walls. Four flues are separately located just above the hearth under the burners. The furnace shown in Fig.4(b) has the same geometry as in Fig.4(a) and is equipped with the FDIregenerative burners. In Fig.4(b), two sets of regenerative burners (in total four burners) are equipped. Two burners along one of the side walls are simultaneously in frring mode while burners along the other side wall behave as a flue. In the calculation no other flue has been taken into account No other flue is considered. The fmng mode switches typically every 15-20 seconds. While the furnace is in practice thennally transient with cyclic manner, the numerical simulation assumes. a steady state of the furnace with burners along one of the side walls continuously in fIring mode with preheated air of constant temperature. Table 1 shows the inlet condition. Total thermal input is defmed as the sum of fuel energy and the enthalpy of preheated combustion air. The forge furnace shown in Fig.5 is box-shaped with its inner dimension being 4000 x 2700 x 8800 mm. A pair of steel billets (800 x 800 x 6600 nun) are charged at 300 mm above the hearth. Fig.5(a) shows the forge furnace equipped with 10 conventional oil burners. A flue 5 |