| Nuclear main pump is the only rotating moving part in nuclear island, which is the "heart" of nuclear power plants. Nuclear main pump is also the main energy-consuming equipment in nuclear power plants. So it has great energy-saving significance to study efficient hydraulic model of mixed flow nuclear main pump to improve the efficiency of real nuclear main pump. At present, domestic research on nuclear main pump is still in its infancy, and there are few outstanding nuclear main pump hydraulic models. So in order to design a high efficiency nuclear main pump hydraulic model, studying the influence of nuclear main pump flow components and other factors on the hydraulic performance of the nuclear main pump has become the key to the localization of nuclear main pump.The different blade trailing edges of mixed flow nuclear main pump impeller, the structure of guide vane(blade thickness, blade trailing edges, blade distribution mode), the matching relationship between the impeller with the diffuser and volute have an important influence to the hydraulic performance, which also affect the internal flow characteristics of nuclear main pump. In this paper, a self-designed nuclear main model pump is the research object. In order to obtain a better performance hydraulic model pump, the influence of different impeller blade trailing edges, different guide vane blade trailing edges, different guide vane blade thickness, different diversion body structures on the hydraulic performance of the nuclear main model pump are studied in detail by CFD numerical simulation. The main work and results achieved are as follows:1. According to the design theory of the mixed flow pump impeller, this paper combines with the velocity coefficient method and the software CFturbo to design the nuclear main pump impeller. And the impeller model is designed by a series of operations, such as 3D modeling, meshing generation, and numerical simulation.2. In order to improve the hydraulic performance of the model impeller, impellers with different blade trailing edges are designed. Through analyzing relative velocity distribution of impeller outlet and the load distribution of impeller blade, the results show: when the leading face of vane is rounded, the hydraulic efficiency value of impeller is the highest.3. In order to study the influence of guide vane on the hydraulic performance of the model pump, the guide vanes with different blade trailing edges and blade thickness are designed. The internal flow field is analyzed by CFD numerical simulation. The results show: the different blade trailing edges of guide vane have little influence on the hydraulic performance of the model pump. Within a certain range, the hydraulic efficiency of the model pump gets increased with the decreasing of the guide vane blade thickness. The changing of the thickest position at the vane blade has little influence on the hydraulic performance of the model pump.4. In order to study the influence of different diversion body structures on the hydraulic performance of the model pump, the diversion bodies with different diameters and diffusion angles and guide vane whose blades are differently arranged are designed, the internal flow field is analyzed by CFD numerical simulation. The results show: for the model pump with the guide ring and guide vane whose blades are symmetrically arranged, when the scheme of guide ring is L=15mm、θ=15?, the hydraulic efficiency value of model pump is the highest; For the model pump without the guide ring but the guide vane whose blades are not symmetrically arranged, with the increasing of the angle γ1, the calculation of the pump hydraulic efficiency value increases firstly and then decreases. When the angle γ1 is 24?, the hydraulic efficiency value of model pump is the highest; For the model pump with the guide ring and guide vane whose blades are not symmetrically arranged, when the scheme of guide ring is L=15mm、θ=15? and the angle γ1 is 24?, the hydraulic efficiency value of model pump is the highest. |
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