中央喷射型喷嘴颗粒分布准则关系式

Criterion relation of particles distribution for CJD nozzle

建立闪速炉中央喷射型精矿喷嘴实验模型,用接粒称重冷模实验方法研究喷嘴控制下的颗粒分布量纲一的准则关系式。研究结果表明:反应塔内颗粒分布受控于绕流雷诺数Red和修正弗劳德数Fr′综合作用,大Red或小Fr′使颗粒集中分布于喷嘴正下方区域;Red对颗粒分布的影响比Fr′的影响大;Red和Fr′可以将实验范围内表征各工况颗粒分布均匀性的颗粒比面密度均方差σ和塔中心区域颗粒质量分数x1二元拟合为非线性指数函数,实验关联式分别为σ=0.001 2exp(2.916Red0.167 1/Fr′0.099 3),x1=11.81exp(-39.15Red-0.400 9/Fr′-0.242 5),σ与x1近似正相关;σ相同的条件是投料量增大倍数ns和分布风流量增大倍数ndis关系式满足ndis=ns1.341 4。

An experimental model of flash furnace with CJD nozzle was built, the criterion relation of particles distribution was studied, employing cold experimental methods such as receiving particles from air flow and weighting particles. Results show that particles distribution in the reaction tower is controlled by the combined action of streaming Reynolds Number Red and modified Froude Number Fr′, the big Red or the small Fr′ makes the particles concentrated on the central zone under the nozzle. The effect of Red on the particle distribution uniformity is larger than that of Fr′; Red and Fr′ are fitted as the nonlinear exponential function with two uniformity indexes of particles distribution, i.e. the mean square error of surface density ratio σ and the central mass fraction x1 within the scope of experimental data, and the experimental functions are σ=0.001 2exp（2.916Red0.167 1/Fr′0.099 3） and x1=11.81exp（-39.15Red-0.400 9/Fr′-0.242 5）. σ is positively related to x1, the condition that σ is the same is that the amplification factor of concentrate loading ns and distribution air ndis satifies ndis=ns1.341 4.