| The paper belong to the "50th" national important science and technology project "Research & Design of Accessory Production and industrialization's exploitation of the light small-moving type and big self-running type spray-irrigate unit (Project's number: 2002AA6Z3161)".The self-priming pump is widely used in fields of agriculture and industry for its unique function of self-priming. Self-priming pump is the key equipment in the aspect of agriculture modernization. Presently, in our country there produced basically the centrifugal self-priming pumps whose mode of self-priming is gas-liquid mixing, but this structure make the pump's volume and weight more big so as to convey more hardly. In addition, pump with this structure has some shortage on its performance.On the basis of the comprehensive analysis of the principle of self-priming pump, this paper bring forward a new type of self-priming pump named jetted self-priming pray pump in order to improve the pump's efficiency and performance of self-priming by improving the method of hydraulic design and the structure of self-priming. There are two innovations on pump's structure, one is the jetted self-priming set, and another is the volute of guide-vane style. The jetted self-priming set can improve the performance of self-priming and the efficiency of whole unit so as to reduce the running cost. The volute of guide-vane structure can transform the kinetic energy to pressure energy as soon as possible, and improve the capacity of separating gas and liquid for the more balance flow in it. Then the numerical simulation of the internal 3-D flow field in the inlet of the pump was carried on for the numerical simulation can describe the information of the internal flow. Finally produce one self-priming pump and do experiment for the pump, analysis the set's effect to power, velocity of flow, and performance of self-priming, also using experiment to validate the result of calculation. Here is the main points of my work:1. Summarize the present state of the research and fruits of formers research, bring out a new theory and method of design of jetted self-priming pump, also point out signification of theory and practice on this paper.2. Through the 3-D design software Pro/ENGINEER, the 3-D solid model of pump and self-priming set were constructed, then apply mixed structure grid generation technique to the internal flow area of the inlet of jetted self-priming pump, grid density is controlled by the distribution functions P, Q, R.3. Summarizing the condition of the turbulence and present states of development in calculate flow dynamics, also describe the solving model detailed. Using the trade CFD software FLUENT to numerical simulate the 3-D uncompressible turbulent flow field within inlet of the pump, confirm the solving field and boundary condition, RNG k-εtwo-equation turbulent mode was adopted, the limited volume method was used to disperse the control equation, The SIMPLE's algorithm was used to solve the equation, the result of calculation was analyzed and investigated. The result offer some theory foundation for perfecting performance of self-priming pump and theory of hydraulic design.4. Using the theory and method above, jetted self-priming pump was designed and produced, and do experiment on the performance of pump. In this paper thorough research was done on the position and acreage of circumfluence hole, circumfluence set and nozzle, then on the base of many experiments the best parameters were gotten so as to resolve the conflict between self-priming performance of the pump and efficiency of pump.5. Finally, the results of calculation and experiment were both summarized and analyzed synthetically, then a suit of theory and method of design was get in reason, which be provided with guidance significance for actual appliance in engineering.
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