锰矿预热窑内气固换热的数值模拟

Numerical simulation of gas-solid heat exchange in manganese ore preheating kiln

为了直观地得到某预热窑内烟气、物料的温度分布和气体流动状态,从而调整实际生产中预热窑的进气量、入口烟气速度及烟气出口压力等参数,采用数值模拟的方法建立了工业尺度的矿热炉炉顶预热窑三维模型,并用多孔介质模型和双温度方程研究窑内的温度场变化.研究结果表明:高温气体穿过进气梁上的进气孔时最大速度为45.27 m/s,与实测值44.6 m/s相差1.51%;气体入口附近形成近椭圆形的高温区域,出口附近的气体温度低于400 K,气体的热量利用率高;预热15,30,60 min时固体物料的最高温度分别为585.13,697.09,765.08 K;预热60 min时,预热窑底部出口的物料温度范围为524.8~762.29 K,实际生产中预热窑出口处物料最高温度在450~550℃范围内,符合预热窑实际工况.

In order to obtain the gas flow status and temperature distribution of flue gas and materials in the preheating kiln,the parameters such as the air intake,inlet flue gas velocity and flue gas outlet pressure of the preheating kiln in actual production can be adjusted,this paper adopts the method of numerical simulation and establishes a threedimensional model of the industrial-scale preheating kiln,and uses the porous media model and the double temperature equation to study the temperature field changes in the kiln.The research shows that:The maximum velocity of the high temperature gas when passing through the inlet hole on the inlet beam is 45.27 m/s,which is 1.51%error compared with the measured value 44.6 m/s.A near-elliptical gas high temperature area is formed near the gas inlet,and the gas temperature near the outlet is lower than 400 K,and the heat utilization rate of the gas is high.The maximum temperature of the solid material is 585.13,697.09,765.08 K when preheating for 15,30,60 min,respectively.When preheating for 60 minutes,the temperature range of the material at the bottom of preheating kiln is 524.8~762.29 K,the high temperature is in the range of 450~550℃,which is in line with the actual working conditions of the preheating kiln.