三级活塞推料离心机数值模拟与操作参数优化

针对新型三级活塞推料离心机的研发，在转鼓尺寸和物料增大情况下，操作参数对分离过程中转鼓内侵蚀现象和分离效率有重要影响。采用样机实验结合CFD数值模拟，对三级活塞推料离心机进行三维建模和仿真，并利用密集离散粒子模型(DDPM)模拟侵蚀过程。基于粒度分析可知，氯化钠颗粒粒径dm为0.070~0.200 mm时，随颗粒粒径增加，固相对离心机转鼓内部的侵蚀越大。结合响应面分析法可知，响应模型各因素的交互影响明显，以更高分离率与更低侵蚀率作为评价指标，得出最优值为推料频率40次/min、转鼓转速1431 r/min、进料浓度60%。与实验数据进行对比，模拟结果的误差在可接受范围内。

Numerical simulation and operating parameter optimization of three-stage piston pusher centrifuge

In response to the need for improvement of the new three-stage piston pusher centrifuge such as the gradual increase in production capacity, the diversification of raw materials and the optimization of the centrifuge structure, the vital influence of operating parameters on the erosion phenomenon and separation efficiency in the drum during the separation process has been confirmed. The simulation software's pre-processing parameters were concluded based on the raw materials' experimental sampling and the corresponding piston pusher centrifuge provided by the manufacturer, starting from the material's particle size. The three-stage piston pusher centrifuge was modeled in three dimensions, using discrete phase and continuous phase. The solid-liquid separation process was simulated by the combined method and the dense discrete particle model (DDPM) was used to simulate the erosion process. Finally, the data was analyzed in combination with experiments to obtain the size and rules of the erosion of each structure by the particles during the separation process and the new equipment's optimal operating parameters. It was concluded that when the particle size dm of sodium chloride particles was between 0.070 mm and 0.200 mm, as the particle size increased, the solid phase's erosion inside the centrifuge drum became greater. Using prototype experiments and CFD numerical simulation combined with response surface analysis, the interactive influence of each factor of the response model was evident. The influencing factors from high to low were drum's rotating speed, feed concentration, and push frequency for the separation rate. For the erosion rate, the influencing factors from high to low were the drum's rotating speed and the feed concentration. Considering higher separation rate and lower erosion rate as evaluation indicators, the optimal value obtained as push frequency of 40 times/min, drum's rotating speed of 1431 r/min, and feed concentration of 60%. Compared with the experimental data, the simulation error was within the acceptable range.