| Due to the medium of centrifugal slurry pumps transport are fluid-solid two-phase medium, there is great different of internal flow field between centrifugal slurry pumps and clean water pumps. Therefore, the design of the former is more complex and its design theory as well as method are not perfect right now. In terms of performance, the main criticisms are its working head lower than design head, low efficiency and severe wear. So, it is a kind of equipment whose performance should be promoted rapidly in modern safe and effect industrial production. Thus, the optimal design of centrifugal slurry pumps to improve its performance is very meaningful.This article, at the basic of concluding the researches and study achievements of our predecessors, in order to provide a new design method and useful reference to improve the structure of centrifugal slurry pumps. A centrifugal slurry pump with a specific speed of 75 was chosen as the research object. Plackeet-Burman screening experimental design, uniform experimental design and the method of the RBF neural network combined with NSGA-Ⅱ genetic algorithm were utilized to multi-optimal design the model pump. The major work are as following.1. The researches and studies of domestic and overseas about experiment,simulation and optimization of centrifugal slurry pump were collected and summarized, and applications of intelligent optimization algorithms in fluid machinery were analyzed.2. In order to offer mathematical model and theoretical support for CFD calculation of centrifugal slurry pump, basic equations of slurry pump were derived and established based on two-fluid model. MATLAB was used to obtain the projection curve equation of cylindrical blade with adjustable wrapping angle of centrifugal impellers, and the routinization of blade drawing was realized. Pro/Engineer was used to build the 3D model of slurry pump, ICEM was used to divide girds, and gird independence verification was finished.3. The difference of external characteristic curves between clean water and fluid-solid two phase working conditions of model pump were compared by using the CFD numerical simulation method. Experimental verification was finished atfluid-solid two phase working condition. The difference of distribution of static pressure at z=0 section of impellers and volute runner. Difference relative velocity vector of fluid phase and solid phase at z=0 section of impellers runner at different initial concentration of solid phase, different grain diameter and different grain density were compared, and the reasons of those difference were analyzed.4. Design Expert 8.0.5b was used to make Plackett-Burman screening experimental design to pick out 3 structural parameters as the optimization variables from 12 structural parameters of model pump, because there are too much structural parameters may affect the high efficiency area and highest efficiency of centrifugal slurry pump. 37 levels uniform experimental was finished and the training and testing samples of RBF neural network was established. RBF neural network was used to fit the relationship between the variables and objectives.5. Optimal design of centrifugal slurry pump was based on NSGA- Ⅱ genetic algorithm.CFD was applied to compute the 2 extreme value individuals which were chosen from the Pareto optimal solutions. The difference of external characteristic curves, distribution of absolute pressure at z=0 section of impellers runner and volute runner, relative velocity vector of fluid and solid phase. Distribution of turbulence kinetic energy, distribution of solid concentration of pressure blades, blades back,front shroud and back shroud at z=0 section of impellers runner were compared between 2 extreme value individuals and initial individual. Experimental verification of optimal efficiency individual was finished and its Q-η curves were compared to initial individual. It was found that with utilizing NSGA-Ⅱ genetic algorithm, the effect of optimizing the performance of centrifugal slurry pump was remarkable. |
PDF Full Text Request