| Disc pump with radial straight blade is a centrifugal pump with special structure ofimpeller, transmitting medium using the boundary layer effect. As a recent researchdevelopment and gradually popularized new pump, there is no mature disc pump theory anddesign method can learn, and have not in-depth study at home and abroad. The papersupported by the project of “Research on Subsea Mud-lift Drilling Technology(2008ZX0526-001-12)”sponsored by National Science and Technology Major Special Projectamd the project of “Digital Prototype Development and Performance Predictive Study of NewType Discontinuous Blade Pump Used for Pumping Multiphase Medium(11CX06066A)”.Numerically simulations in the whole flow passage of the disc pump, predictive study onaxial force and radial force, analysis on the influence of impeller parameters on pumpperformance, strength and modal analysis on the impeller based on fluid-structure interactionand a plan of multi-stage disc pump etc are carried out to solve the technical problems ofhydraulic performance and structure reliability, providing technical support for localization ofdisc pump.The main research work and creative achievements are as follows:1. Predictive study on hydraulic performance, axial force and radial force of DiscpumpIn this paper, three dimensional numerically simulations under different workingconditions were performed in the whole flow passage of the disc pump with computationalfluid dynamics software Fluent. The effect of blade width, blade shape etc on the head andefficiency of the disc pump were studied. The calculation results indicate that in a certainrange, the pump performance can be effectively improved by decreasing the blade width andtaking the trapezium as blade axial sections. The analytical results can be used as theoreticalbasis for structure design, optimization and performance improvement of the disc pump.As for the problem of axial force and radial force, on the basis of analysis of axial forceand radial force causes, numerically simulations are performed in the whole flow passage ofthe disc pump with Fluent.The pressure distribution of the pump axial end and the impellersurfaces are obtained and the value of axial force and radial force is calculated.The resultsshow that axial force generated by pressure distribution of outer surface of impeller accountedfor a very large proportion of the total axial force. The radial force reaches minimum value atthe design condition, which is consistent with the theoretical analysis. 2. Strength analysis on the impeller of Disc pump based on fluid-solid interactionBy means of finite element software, its impeller structural strength behavior underworking condition has been gotten through conducting strength analysis based on fluid-solidinteraction. Calculating the pressure distribution of its impeller under different workingconditions with Fluent software, and implementing strength check for impeller with ANSYSand Workbench software platform make us obtain the primary critical sites and regularity ofstress and strain distribution, as well as impeller structural improvement at critical area. At thesame time, the influence of link-arm parameters on impeller strength is also studied. Thecalculation results indicate that the most critical area for the new type of pump is the junctionof link arm and disc on account of stress concentration, but the improvement lessens themaximum stress enormously, boosts safety factor and working life strikingly.3. Modal analysis on the Disc pump with radial straight blade based on fluid-solidinteractionThe influence of the fluid pressure, centrifugal force on the modal characteristics of discpump impeller is studied. The fluid pressure size and distribution of impeller under differentworking conditions are obtained with the help of Fluent software. By means of Workbenchsoftware platform, static modal Analysis，fluid pressure and rotating centrifugal force modalcharacteristics analysis on the impeller is conducted. The caculated results are compared andanalyzed. The test has also been processed to varify correctness of the results of numericalsimulation. At the same time, the impact trend of the link arm radius and link arm position onthe natural frequency of disc pump impeller is discussed. The results show that each vibrationtype of Static modal and prestressed modal is similar. The natural frequency and theamplitude are little different. At last, the critical speed of pump rotor is calculated, providing anumerical basis for increasing the reliability of the disc pump.4. Study on the plan of a horizontal split casing multi-stage Disc pump with highreliabilityIn order to improve the disc pump reliability and wear resistance further, this paperintroduces a kind of horizontal split casing multi-stage disc pump. The multistage pump maininnovation is it selects a impeller with special structure. The impeller cover plate internalsurface have special forms of "corrugation" to replace the ordinary impeller blades, changethe traditional meaning on the blade concept. Contrasted with traditional multistagecentrifugal pump, this kind of pump is wear resistance, high reliable etc. |
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