刘丽艳，刘小康，樊东东，李昱奇，谭蔚，朱国瑞
AuthorsHTML:刘丽艳，刘小康，樊东东，李昱奇，谭蔚，朱国瑞
AuthorsListE:Liu Liyan，Liu Xiaokang，Fan Dongdong，Li Yuqi，Tan Wei，Zhu Guorui
AuthorsHTMLE:Liu Liyan，Liu Xiaokang，Fan Dongdong，Li Yuqi，Tan Wei，Zhu Guorui
Unit:天津大学化工学院，天津 300072
Unit_EngLish:School of Chemical Engineering and Technology，Tianjin University，Tianjin 300072，China
Abstract_Chinese:为了解决卧式螺旋卸料离心机(简称卧螺离心机)进料分布器在处理含硬质颗粒物料过程中存在的磨损问题，提高其使用寿命，采用数值模拟方法研究进料分布器内的速度矢量、流线变化及剪切力特性，分析了导致分布器磨损的原因，对分布器结构进行了优化设计．数值模拟结果表明，流体流出时颗粒对分布器造成的剧烈碰撞是磨损的主要原因，碰撞主要发生在分布器入口附近中心壁面区和出口处内凹形外侧区域．针对磨损原因，依据质点从旋转出口自由甩出的运动轨迹方程设计流道型线，并将双流道改为三流道，设计出新型分布器结构．对两种分布器的壁面剪切力分析结果表明，新型分布器壁面剪切力峰值从12.7Pa减小到10.1Pa．在流道入口附近，新型分布器的壁面剪切力略大于原分布器；在流道出口处，新型分布器的平均壁面剪切力由原来的10.2Pa降低到4.2Pa．对两种结构的分布器进行可视化试验，获得两种结构分布器内流体质点运动轨迹线．结果表明：1650r/min和2310r/min转速下，示踪颗粒的速度方向偏转角度分别从86.78°和64.87°下降到44.33°和26.87°；990r/min和1320r/min转速时新型进料分布器中颗粒近似径直飞出分布器而不发生偏转．分布器中流体对壁面撞击力度减小，分布器磨损减弱，该优化结构可代替原有分布器，在处理硬质颗粒物料等易磨损工况下，有望提高整机寿命．
Abstract_English:To solve and enhance the service life of the decanter centrifuge feed distributor’s abrasion problem during the processing of hard particles，numerical simulation methods were used to analyze the vector velocity，streamline changes，and shear force characteristics of the distributor．The cause of the distributor’s wear was analyzed and the distributor’s optimum design was studied. Numerical simulation results show that the main cause of wear is the extreme impact of particles on the distributor，and the collision occurs primarily in the central wall region and the concave exterior region．The flow path profile is designed for wear according to the equation of the motion trajectory where the particle exits freely from the rotary outlet and the double-flow channel is converted into the three-flow channel to design a new type distributor structure. The results of the study of the two distributor’s wall shear forces show that the peak value of the current distributor’s wall shear force is reduced from 12.7Pa to 10.1Pa. Near the inlet of the distributor，the new type distributor’s wall shear force significantly higher than that of the original distributor；at the distributor’s outlet，the new distributor’s average wall shear force is reduced from 10.2Pa to 4.2Pa. Visualization tests were performed on both distributor types，and the trajectories of the fluid particles were obtained in both distributor types. The findings show that the deflection angles of the tracer particles decrease from 86.78° and 64.87° to 44.33° and 26.87° at 1650r/min and 2310r/min respectively. The particles in the new type distributor flow out of the distributor at 990r/min and 1320r/min，without deflection. With the new distributor type，the impact force of the fluid on the wall is reduced，and the distributor wear is weakened. The optimized structure will replace the original distributor and is used in hard-wearing conditions such as processing hard granular materials. It is predicted to enhance the life of the whole machine.
Keyword_Chinese:卧式螺旋卸料离心机；进料分布器；壁面磨损；数值模拟；结构优化；可视化试验
Keywords_English:decanter centrifuge；feed distributor；wall wear；numerical simulation；structural optimization；visual experiment

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