淹没条件下分散射流对浓密板结料浆的扰动试验研究

Experimental Study on Disturbance of Dense Slurry by Dispersive Jet in Submerged Environment

为研究浓密机喷嘴射流对浓密料浆的影响效应,基于室内试验(喷嘴变径、压力、喷口分布、高能量低衰减)和工业试验(射流时间、扰动范围、料浆浓度)的方法,考察喷嘴射流对料浆的扰动性能,通过计算扰动区域、渗透性能及料浆影响因素确定射流与浓度的匹配关系,构建了流场作用下的CFD数值模型,将取得的成果应用到实际中。表明:1)锥体安装射流系达到剥离板结料浆的目的,为获得稳定的底流浓度提供了方法;2)浓密机在满载状态下工作16 h后启动射流系统是最佳时间,论证了料浆底流浓度与扰动系统之间的时空响应关系:分层纵向上扰动时长为20、15和9 min;3)研究了喷嘴“梅花”型布置射流扫描完全覆盖板结区域,推导了相邻喷口流场最大体积量,验证了喷嘴每层数量20、14、9、6时易形成弧形相切面,利于全区域内料浆的剥离;4)以屈服应力和黏度评价指标考察剪切破坏及压密脱水性能,利于实现浓密机底流浓度稳定。

In order to study the effect of thickener nozzle efflux on thickening slurry,the disturbance performance of nozzle efflux on slurry was investigated based on laboratory tests(nozzle diameter reduction,pressure,nozzle distribution,high energy and low attenuation)and industrial tests(jet time,disturbance range and slurry concentration).The matching relationship between jet efflux and concentration was determined by calculating disturbance area,permeability and slurry noise factors.The CFD numerical model under the action of flow field is constructed,and the results are applied to practice.The results show that:1)Cone installation jet system can achieve the purpose of stripping plate slurry,and provide a method for obtaining stable underflow concentration;2)The optimal time to start the jet system is 16 h after the thickening machine works in full load condition.The spatio-temporal response relationship between slurry bottom flow concentration and the disturbance system is demonstrated.The longitudinal disturbance duration is 20 min,15 min and 9 min in stratification.3)The“plum blossom”arrangement jet of the nozzle was studied to completely cover the plate area,and the maximum volume of the flow field of the adjacent nozzle was deduced.It was verified that when the number of each layer of the nozzle was 20、14、9、6,it was easy to form a curved section,which was conducive to the stripping of slurry in the whole area.4)Using yield stress and viscosity evaluation indexes to investigate shear failure and compaction dehydration performance,which is conducive to achieving stable underflow concentration of thickener.