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本文包括:(1)炉膛内钢坯加热数学模型;(2)最佳炉温及最低燃耗在线模型。 采用一维模型,应用Hottel多层无限大气层间的辐射热交换计算方法,把各火焰射流的作用,当量地看作是夹在上下炉气层之间的一个火焰层。它的平均温度t_f可以根据Ricou-Spalding射流吸入经验公式,计算火焰和周围炉气间的质量交换,再按热平衡方程把t_f计算出来。钢坯内部传热按一维导热问题,用差分求解。 还建立了一个较简单的炉膛传热仿真模型,据此求出各炉段单位炉温对出钢平均温度及中心温度的变化率θ_m/Ti及θ_s/Ti。还可确定最小燃耗函数P的各炉段加权系数W_i。 令各段在线炉温调节量ΔTi=(T_(i,max)—T_(i,o))—ΔT_i′,这就能在线性规划中用ΔT_i′代替ΔTi作为未知量以满足非负条件。这时目标函数P_(min)=-sum (W_iT_i′)。文中还附有一个说明各段炉温按上述线性规划进行最佳控制的例题。
This article includes: (1) Mathematical model of billet heating in the furnace; (2) On-line model of the best furnace temperature and minimum fuel consumption. A one-dimensional model was used to calculate the effect of each flame jet by using Hottel multi-layer radiative heat exchange calculation method between infinite layers of atmosphere. It is equivalently regarded as a flame layer sandwiched between upper and lower gas layers. Its average temperature t_f can be calculated according to Ricou-Spalding jet inhalation empirical formula, mass exchange between the flame and the surrounding furnace gas, and then according to the heat balance equation t_f calculated. Billet heat transfer by one-dimensional heat conduction problems, using differential solution. A simpler simulation model of furnace heat transfer was also established. Based on this, the change rates of θ_m / Ti and θ_s / Ti for tapping temperature and center temperature of each furnace were obtained. It is also possible to determine the weight of each furnace section W_i of the minimum fuel consumption function P. FIG. Let the online furnace temperature adjustment ΔTi = (T_ (i, max) -T_ (i, o)) - ΔT_i ’, which can be used in the linear programming to substitute ΔT_i’ for ΔTi as the unknown to satisfy the nonnegative condition. Then the objective function P_ (min) = - sum (W_iT_i ’). The article also includes an example of how each section of the furnace temperature should be optimally controlled according to the linear programming described above.