双蜗壳混流泵内部流场数值模拟及叶轮力学特性分析

发布时间：2018-03-26 10:39

本文选题：双蜗壳　切入点：混流泵　出处：《华中科技大学》2011年硕士论文

【摘要】：随着科学技术的不断发展,现代工农业对于水力机械各方面的性能也提出了更高的要求,在空化和汽蚀现象不是很严重的情况下,效率,强度和稳定性无疑成为三个最为重要的性能指标,效率关系到对能量的利用,强度关系到做功部件叶轮的寿命,而稳定性则关系到机组是否能安全,正常的运行,事实上他们之间并不是相互独立的,而是紧密联系在一起的,因此探讨这三个重要的性能指标之间的关系也就成了水力机械设计过程中不可避免的敏感话题。本文以某一双蜗壳式混流泵为研究对象,以计算流体动力学为理论基础,运用先进的计算机数值计算技术,对混流泵整机模型在多个工况点下进行全三维的定常湍流数值模拟,揭示了三种特征工况点下其内部流场的主要机理,同时对叶轮做出必要的优化改型,从而提高了设计工况点下的效率,为探讨混流泵机组的稳定性,还对上述计算模型进行非定常的湍流数值模拟,详细分析了混流泵内部流场各监测点压力脉动的变化情况。此外,大量文献报道由于水力机械机组的叶轮受到持续的疲劳破坏,其叶片发生裂纹或者断裂现象,并且整个机组还伴随着强烈振动与机械噪音,对此,本文应用流固耦合技术对混流泵叶轮进行静力强度和模态的力学特性分析,为混流泵通流部件的强度设计与校核及机组的振动分析提供一定的参考依据。综合以上的因素,我们必须注意到在水力机械设计阶段不能只是一味地追求效率,还应顾及强度及稳定性方面的制约,以研制和开发出既高效节能,又运行平稳安全可靠的水力机械产品为出发点,不断完善其结构和性能。
[Abstract]:With the continuous development of science and technology, modern industry and agriculture also put forward higher requirements for the performance of hydraulic machinery in all aspects. In the case of cavitation and cavitation, efficiency is not very serious. Strength and stability are undoubtedly the three most important performance indexes. Efficiency relates to the utilization of energy, strength relates to the life of the impeller, and stability relates to the safety and normal operation of the unit. In fact, they are not independent of each other, but are closely related. Therefore, exploring the relationship between these three important performance indicators has become an inevitable sensitive topic in the process of hydraulic machinery design. In this paper, a double volute mixed-flow pump is used as an object of study. Based on the theory of computational fluid dynamics (CFD), advanced computer numerical calculation techniques are used. Three dimensional steady turbulent numerical simulation is carried out on the model of mixed-flow pump under multiple operating conditions, which reveals the main mechanism of internal flow field at three characteristic operating conditions, and makes necessary optimization modification of impeller. In order to study the stability of mixed-flow pump unit, unsteady numerical simulation of turbulent flow is carried out on the above model. The variation of pressure pulsation at various monitoring points in the flow field of a mixed-flow pump is analyzed in detail. In addition, it is reported in a large number of literatures that cracks or breakages occur in the blades of hydraulic machinery units due to the continuous fatigue failure of their impellers. And the whole unit is accompanied by strong vibration and mechanical noise. In this paper, the static strength and modal mechanical characteristics of the impeller of the mixed flow pump are analyzed by using fluid-solid coupling technology. It provides a certain reference for strength design, check and vibration analysis of flow passage parts of mixed-flow pump. Taking the above factors into account, we must note that in the design phase of hydraulic machinery, we should not only pursue efficiency blindly, but also take into account the constraints of strength and stability in order to develop and develop high efficiency and energy conservation. Running smoothly, safe and reliable hydraulic machinery products as the starting point, constantly improve its structure and performance.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH313

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