Optimal Design Of The Accelerator Disk In A Two-Stage Piston Pusher Centrifuge

In this paper, optimal design of the structure of the accelerator disk in a P-85two-stage piston pusher centrifuge was performed to improve the material brokenphenomenon due to the accelerating difference in the production. The3-D model ofthe accelerator disk was set up with the Gambit software. Numerical simulation wasperformed with the Fluent, a widely-used computational fluid dynamics software, tostudy the flow field in the disk. The material motion in the disk was obtained, and theoverall analysis for its performance was realized.In this work, the optimal design for blade curve and geometric outline of theaccelerator disk was firstly performed based on the theory of the blade rotatingmachinery in the centrifuge. The blade curve optimization concentrated on compositeblade, in which the twisted and cylinder blade was used for the inlet and outlet,respectively. This work emphasized on the optimization the blade curve for the outlet,for which variable angle helix, involute and controllable angle curves were selected.By analyzing the martial motion and comparing the material velocity and turbulenceintensity of the flow field in the disk, it was found that the curve with the outlet angle15°and the wrap angle90°was the best blade curve. The geometric outlineoptimization was performed based on the blade curve study. The simulation resultsshowed that long blade had the best combination property on the premise of the safetyof blade stress. Thus, the best blade structure was obtained for the accelerator disk.Pilot and industrial experiments were then performed to analyze the validity ofthe simulation results and the effectiveness of the optimized accelerator disk.According to the pilot experiment results, the path lines of the material and the brokenmaterial with different disks were well concordant with the simulation results, whichcertified the correctness of the simulation methods. In the industrial experiments, thedisk fractured at the end part. Based on the optimized results of the geometric outline,a45°cutting angle was added, resulting in the good operation. The water content ofcake and material particle size distribution was then also investigated. It was shownthat the enhanced accelerator disk lowered the water content of cake to some extent,and the collision between the material and screen cloth were also relieved, whichguaranteed the particle completeness. To overall analyze the performance of the optimized accelerator disk, materialparticle size, rotating velocity of the accelerator disk and the blade numbers wereselected as variables to simulate the flow field. The results showed that the optimizeddisk had the good adaptability. To meet the requirements of equipment enlargement,assistant blade was added between two successive blades in the P-100type centrifugeaccording to the simulation results. It was found that the added blade served toaccelerate the material to some extent.Moreover, secondary development was conducted for the numerical simulationprocess with the Visual Basic language, and a simple operation simulation software ofthe accelerator disk was obtained. Users just inputted the basic parameters of theaccelerator disk, and the software could set up model, calculate and output resultsautomatically.In conclusion, numerical simulation, experiment study and the softwaredevelopment were performed for the accelerator disk in a two-stage piston pushercentrifuge. This work provides the basis for the use and improvement of theaccelerator disk.