瞬态摩擦荷电对水口壁面夹杂物黏附动力学影响机制研究

Based on the close relationship between the clogging of submerged entry nozzle and the adhesion-deposition of inclusions in molten steel, the correlation and mechanism among adhesion process of inclusions and transient triboelectrification as well as its inducing electric field will be studied in this proposal. According to introducing the motion friction characteristics of inclusions into the clogging layer growth of the submerged entry nozzle, the correlation and mechanism among the clogging of submerged entry nozzle and the transient triboelectrification, which induced by the relative movement among inclusions, inner surface of submerged entry nozzle and molten steel will be explored. The dependency relationship among friction state, interface wetting characteristics and transient triboelectrification will be evaluated emphatically on the basis of the displacement current effect of friction between inclusions and inner surface of nozzle. The clogging behavior of the submerged entry nozzle under different inclusions and flow field states will be measured and analyzed. The effects of parameters, such as contact angle, flow field, friction status and induced electric field, on the adhesion dynamics of inclusions will be investigated. Combining the methods of fluid dynamics simulation of discrete element, surface phase analysis and the frequency domain signal testing, the inherent regularity between the coupled effect of flow field and electric field on the clogging of submerged entry nozzle will be confirmed. The purpose is to clarify the main physico-chemical mechanism of the migration, adsorption and sintering of the inclusions into submerged entry nozzle. This project can established the foundation for the theoretical system of transient triboelectrification of inclusions in the molten steel, and provide new ideas and methods for the design and anti-clogging of submerged entry nozzle.

本项目针对浸入式水口结瘤堵塞与钢液中夹杂物黏附沉积密切相关的特点，研究瞬态摩擦荷电及其诱导电场因素与夹杂物黏附过程之间的相关性及其作用机制。通过在水口结瘤层生长研究中引入颗粒运动摩擦特征分析，阐明夹杂物颗粒、水口壁面及钢液之间瞬态摩擦荷电与水口结瘤的相关性及其作用规律。围绕夹杂物与水口壁面摩擦的位移电流效应，重在评估摩擦状态、界面润湿特征与瞬态摩擦荷电之间的依赖关系。通过对不同流场和颗粒状态下水口结瘤行为的测试与分析，采用结合离散元的流体力学模拟、表面物相分析和频域信号测试等方法，在综合对比考察润湿角、流场、摩擦状态与诱导电场特征等参量对夹杂物黏附动力学影响的基础上，明确流场-电场耦合作用与水口结瘤之间内在的规律性。旨在阐明夹杂物迁移、吸附、烧结过程中的内在物理化学主控机制。项目可为钢中夹杂物瞬态摩擦荷电理论体系奠定基础，同时为水口材料设计及防堵塞控制提供新思路和新方法。

本项目针对浸入式水口结瘤堵塞与钢液中夹杂物黏附沉积密切相关的特点，研究瞬态摩擦瞬荷电及其诱导电场因素与夹杂物黏附过程之间的相关性及其作用机制。通过在水口结瘤层生长研究中引入颗粒运动摩擦特征分析，明确了钢液流经浸入式水口时产生了摩擦荷电现象，水口表面带有负电荷，钢液内部带有正电荷，阐明了夹杂物颗粒、水口壁面及钢液之间瞬态摩擦荷电性能的影响因素，揭示了荷电性能与水口结瘤的相关性及相互作用规律。通过对不同流场和颗粒状态下水口结瘤行为的测试与分析，采用结合离散元的流体力学模拟、表面物相分析和频域信号测试等方法，在综合对比考察润湿角、流场、摩擦状态与诱导电场特征等参量对夹杂物黏附动力学影响的基础上，观察到水口与钢水之间存在的电场促进了钢液向水口内壁的润湿和附着，而通过电场调控的手段可消除水口与钢水之间的电场作用，改善固-液两相间的润湿性和反应性。另外，采用电场调控后，夹杂物生长、水口材料的溶解与反应以及水口结瘤物的剥落行为均得到有效的抑制，进而使得连铸后的铸坯内部夹杂物数量和尺寸均得到了降低。因此，在明确了流场-电场耦合作用与水口结瘤之间内在的规律性后，通过电位消除法与外加电场等电场调控的方法均可以抑制夹杂物在水口内壁的粘附行为，进而达到有效控制水口结瘤的目的，并且还可以减少夹杂物数量的同时使夹杂物的细化。最终达到控制水口结瘤并提升铸坯质量的目的。综上，本项目阐明了夹杂物迁移、吸附、烧结过程中的内在物理化学主控机制，研究成果为钢中夹杂物瞬态摩擦荷电理论体系奠定了基础，同时为水口材料设计及防堵塞控制提供了新思路和新方法。