【作者】 吴俊；

【导师】 张双全；

【作者基本信息】 华中科技大学 ， 流体机械及工程， 2011， 硕士

【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。更多还原

【Abstract】 With the unceasing development of science and technology, the modern industry and agriculture put all aspects of hydraulic machinery to a higher performance. If the cavitations are not very serious, the efficiency, intensity and stability are three most important performance indices without doubt. Efficiency relates to the utilization of energy, intensity relates to the life circle of impeller, which is the only acting part in the hydraulic machinery unit, and stability relates to whether the unit can be safe, normal movement. In fact, they are not mutually independent, but are related to closely in together. Therefore discussing the relations of the three important performance indices have become an inevitable and sensitive topic in the design process of hydraulic machinery.The article take a mixing pump of double volute as the object of study, and take the computation fluid dynamic as rationale, utilizes the advanced computer numerical calculus technology, and carries on the entire three dimensional steady turbulence numerical simulations under many operating points for the complete machine of mixing pump, also promulgates the dominant mechanism of its internal flow field under three kind of characteristic operating points. Meanwhile makes the essential optimized modification to the impeller in order to raise the efficiency under the design operating point. For discussion mixing pump unit’s stability, also carries on the unsteady turbulence numerical simulations to the above computation model under the design operating point, analysis pressure oscillation changes with the time to test points in its interior flow field in detail. In addition, massive literature report the impeller of hydraulic machinery unit receives the fatigue damage which continues, the blade has the crack or break phenomenon, and the entire unit is also following the intense vibration and the mechanical noise. Regarding it, this article applies the fluid solid coupling technology to carry on mechanics characteristic analysis about the static rating and modality to the impeller of mixing pump, it can provide some references for the flow passage components’ intensity design and the examinations, also the vibration analysis for the entire pump unit.Considering the above factors, we must note clearly that we should not pursue only the efficiency constantly in the design stage of hydraulic machinery, but should take into consideration the restriction about the intensity and stability, and should set a goal that developing products of hydraulic machinery which not only have higher effective and can conserve energy, but also can move steadily, safely and reliably in order to consummating their structure and improving the performance unceasingly.更多还原