| The study of this paper was supported by the China National Key Technology R &D Program-Key Technology and Running strategy of Typical Process Pumps(No : 2011BAF14B00), and A Project Funded by the Priority Academic Program Development of Jiangsu Education Institutions(No:PAPD).The design way of magnetic drive coupling and the internal flow characteristics of magnetic drive centrifugal pump were investigated, and the main achievements of this work are presented as follows.1. The operating characteristics and existing problems of magnetic drive centrifugal pump were briefly introduced. Then the domestic and foreign advances of magnetic drive centrifugal pump and its internal flow characteristics were discussed. Meanwhile, the research status of magnetic drive coupling was summarized.2. The existing design methods of magnetic drive coupling were analyzed and further improved based on the deficiencies of the methods. A novel design method of magnetic drive coupling was established based on the maximum static magnetic torque calculation formula, magnetic eddy current loss torque ratio formula,permanent magnet volume calculation formula, MATLAB programming, finite element calculation and orthogonal test method. Besides, the calculation program,optimization process and design flow were respectively studied.3. The main goal solution and hierarchical sequence method were firstly introduced for multi-objective design and optimization of the combination of magnetic drive coupling. The design program of magnetic drive coupling was then obtained by determination of design variables, creation of objective function,establishment of constraints and automatic operation of the solution process by MATLAB programming. The reliability of the design program was verified by the existing magnetic coupling model in literatures. It was conclude that this designprocedure is simple, reliable, practical and which can been convenient for the design of magnetic drive coupling.4. Based on finite element calculation method, the influence of changes of different geometric parameters on magnetic torque and eddy current loss of magnetic drive coupling was obtained by single factor experiment on designed magnetic drive coupling. After that, the results of orthogonal test on magnetic drive coupling were obtained as follows: the effect order of the studied factors on the maximum static magnetic torque, eddy current losses, the volume of the permanent magnet were tm>r>Lb>ti, tm>r>Lb>ti and tm>Lb>r>ti, respectively. The optimal geometric parameters of the magnetic drive coupling were 80 mm of inner radius for inner magnet, 8mm of thickness and 144 mm of axial length for permanent magnet and 10 mm thickness for yoke iron, that was, r=80mm,tm=8mm,Lb=144mm,ti=10mm. The static and dynamic test device for magnetic drive coupling was applied in experiment on designed magnetic drive coupling. The test results show that the maximum static magnetic torque and the magnetic transfer efficiency of this magnetic drive coupling are 351 N?m and 91.33%, respectively. Therefore, the magnetic properties can meet the design requirements and the design method, which means that it is reliable and reasonable.5. The impeller and chamber of the magnetic drive centrifugal pump were designed based on the velocity coefficient method and the cooling circulation mode was compared and analyzed. In addition, the calculation method of cooling circulation flow was studied and the calculation method of cooling circulation of magnetic drive centrifugal pump was proposed based on calculation formula of pressure drop loss. This calculation method was selected for calculation of the cooling circulation involved in this paper.6. The flow characteristics of the whole flow field of the magnetic drive centrifugal pump were analyzed by the combination of the CFD numerical calculation and the external characteristic test, obtaining the internal flow rule of themagnetic drive centrifugal pump under different working conditions. Then, the heat exchange and temperature distribution laws of magnetic drive centrifugal pump were analyzed based on the fluid thermal coupling technology. Meanwhile, the variation of temperature in the cooling circulation channel, convective heat transfer coefficient, pressure temperature curve were within the scope of this study. The comparison of numerical calculation and experimental results show that the design of the magnetic drive centrifugal pump was reasonable with wide range of high efficiency, and the head and efficiency index all met the design requirements with the results of head 36.3m and 71.5% efficiency. Becides, the numerical calculation was consistent with the experimental curve, and the numerical calculation method was reliable, which could reflect the flow rule of the magnetic drive centrifugal pump. The research on flow characteristics of the whole flow field of the magnetic drive centrifugal pump based on combination of the CFD numerical calculation and the external characteristic test, which obtain the internal flow rule of the magnetic drive centrifugal pump under different working conditions, meanwhile, discuss heat exchange and temperature distribution of magnetic drive centrifugal pump based on the fluid thermal coupling technology, not only analyze the changes of temperature in the cooling circulation channel, but also discuss convective heat transfer coefficient and pressure temperature curve, and then compare the numerical calculation and experimental results, it is conclude that the design of the magnetic drive centrifugal pump is reasonable with wide range of high efficiency, and the head and the efficiency index all meet the design requirements. Therefore, numerical calculation is consistent with the experimental curve, and the numerical calculation method is reliable, which can reflect the flow rule of the magnetic drive centrifugal pump.7. The pressure fluctuation characteristics of the magnetic drive centrifugal pump were discussed based on the unsteady numerical calculation method. After that, the analysis of pressure pulsation characteristics and attenuation variation ruleof magnetic force driving centrifugal pump under different working conditions were conducted, following the results: The dominant frequency in the impeller passage was shaft frequency(fn), main frequency of chamber and cooling circulation flow passage was blade frequency(6fn), and the source of pressure pulsation in the magnetic drive centrifugal pump was the rotor-stator interaction between the impeller and the tongue. In addition, the pressure pulsation in the cooling circulation channel gradually faded along the flow direction of the medium, and the minimum pressure fluctuation amplitude was near the outlet of the return pipe.8. The relationship between the changes of flow guiding pipe and return pipe diameters and the flow performance of magnetic drive centrifugal pump was explored and the influence of different flow guiding pipe and return pipe diameter changes on external characteristics, internal flow field, temperature field and pressure fluctuation characteristics of the magnetic drive centrifugal pump was obtained. It was found that the diameter changes of diversion pipe and return pipe had little influence on the external characteristics and internal flow field of the pump,however, these diameter changes had great influence on internal flow and the decay velocity of pressure fluctuation in cooling circulation channel.When the diameter of the flow guiding pipe was 10 mm or 6mm of the return pipediameter,the pressure and pressure fluctuation of distance sleeve clearance were larger than other diameter parameters and the alternating loads acting on distance sleeve were larger than other diameter parameters, which could cause fatigue failure of the distance sleeve. At the same time, the pressure and pressure fluctuation amplitude of isolation sleeve gap gradually reduced with the decrease of diversion pipediameter or increase of return pipediameter. |
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