桨叶形状对KR法脱硫混合行为影响的数值模拟

Numerical simulation of influence of impellers′ shape on mixing behavior by KR method desulfurization

为了改善KR搅拌法脱硫剂浪费严重的问题,开发3种新型搅拌桨改善铁水和脱硫剂的混合效果。应用CFD技术,以速度场、湍动耗散率和混匀时间为特征,描述液面的卷入能力和内部混合能力。通过对比3种桨形与传统桨形(A桨)的铁水流动结构,分析结构参数和操作参数之间的影响规律。研究结果表明,方形桨(B桨)卷入脱硫剂的能力和改善混合效果强于其他3种桨形,随转速从60 r/min增加到80 r/min,柱状回转区体积减小60%,死区体积减小67%,混匀时间缩短52%;D桨的下倾角和径向斜边改善了搅拌桨下方死区混合效果,随转速从60 r/min增加到80 r/min,死区体积减小51%,混匀时间缩短48%;C桨的卷入能力和混合效果介于D桨和B桨之间;A桨效果最差。

Three new types of impellers were developed to strengthen the mixing effect of molten iron and desulfurizer, in order to improve the serious waste of desulfurizer in KR stirring process. CFD technology was used to describe the entrapping ability of the liquid surface and internal mixing ability with the velocity field, the turbulent dissipation rate and mixing time, respectively. The influence rules between structural parameters and operating parameters were analyzed by comparing the flow structures of molten iron with three new types of impellers and traditional impeller type(A impeller). The results show that the square impeller(B impeller) is better than the other three types impellers in its ability of desulfurizer and improving mixing effect, the volume of the columnar turning zone decreases by 60%, the volume of the dead zone decreases by 67%, and the mixing time decreases by 52%, respectively, with the rotation speed increasing from 60 r/min to 80 r/min of the B impeller. The downward dip angle and radial beveling edge of the impeller D improves the mixing effect of dead zone under the impeller, the dead zone volume decreases by 51% and the mixing time decreases by 48%, with the speed increasing from 60 r/min to 80 r/min. The entrapment ability and mixing ability of the C impeller are between those of the D impeller and the B impeller. And the effect of A impeller is the worst.