【作者】 冯俊玮；

【导师】 王晓放；

【作者基本信息】 大连理工大学 ， 流体机械及工程， 2009， 硕士

【摘要】 离心压缩机广泛用于航天、冶金、石油、化工、能源等部门,在国民经济各领域发挥着举足轻重的作用。作为从动机,离心式压缩机在提高工质压力的同时,也消耗能源,特别是近年来百万吨乙烯工程、大型空分装置等都对国产大流量压缩机的设计、研发提出了挑战。研究表明,扩大工况范围、提高级组运行安全性、提高流动效率、优化流道结构、减少能量损失,必须对离心压缩机内部流动进行深入探究,从而提高大型离心压缩机整体设计水平,这将对我国重大装备制造业的发展及节约能源有重要现实意义和历史意义。本文针对大流量离心压缩机叶轮轮毂比大、叶轮进出口相对宽度大、进出口马赫高,而相对轴向跨距小、叶轮结构刚性差等气动、结构特点,首先利用叶轮机械专用数值分析软件NUMECA,对某事故离心压缩机低压缸大口圈直径的闭式叶轮内部流场进行定常流动数值模拟研究及事故原因分析。完成了该压缩机低压缸整机设计工况性能核算,并验证了数值模拟的物理模型及数学模型的可靠性。通过对运行工况特别是事故工况进行定常数值模拟,分析内部流场结构与叶轮结构的关联及影响,进而揭示事故发生的主要原因。为了更加深入研究叶轮入口气流畸变对叶轮破坏的影响程度,本文还对事故机组低压缸首级进行了非定常流数值模拟,从非定常流动的角度,进一步阐明对大流量高压离心压缩机低压级设计上的关键问题及引起本次事故的重要原因。最后,根据分析结果,针对该事故原因提出了几种改进方案,并对改进方案进行定常及非定常数值模拟,经与原设计比较,确定改进方案,为压缩机改进设计提供技术支持,目前,该压缩机运行正常。更多还原

【Abstract】 The centrifugal compressors play an important role in every field of the national economy, such as aerospace, metallurgy industry, petroleum industry, chemical industry and power plants. As driven machines, the centrifugal compressors consume the power in order to produce the high pressure of working air. In recent years, a big new challenge to the design and research of the domestic compressors with large capacity is posed, especially in the megaton ethylene project and large air separation unit. The study shows that it is very important to enhance the whole design levels of centrifugal compressors with large quantities by expanding the scope of working condition, raising the operating security of sets, increasing the flow efficiency, improving the flow structure, reducing energy loss, and further studying on the internal flow of the centrifugal compressor. These achievements will lead to a realistic and historical significance on the development of our major equipment manufacturing and energy conservation.According to the pneumatic and structure characteristics of the large flow rate centrifugal compressor, such as high hub-tip ratio of the impeller, big relative width ratio between the inlet and outlet of the impeller, high Mach number, small relative axial span and worse structure rigid of the impeller, the correlated investigation is completed in this paper. To begin with, the analysis on the damage of the impeller inlet element in the centrifugal compressor low pressure casing is completed by numerically researching the inner steady flow field across the impeller passages with the commercial software, NUMECA. The investigation includes the performance account of the whole low pressure casing and the reliability certification of physical and mathematical model of the numerical simulation. The main reasons of the accident are revealed through analyzing the relationship between the inner flow field and the impeller structure under the real operating condition. Afterwards, the unsteady flow numerical simulation for the first stage in the low pressure casing is completed in order to find out the extent to which the flow distortion contributing to the impeller damage. As a result, the key point of designing the centrifugal compressor with a large flow rate and high pressure ratio and the accident reasons are further stated.Finally, several improved solutions are proposed based on the steady and unsteady flow numerical investigation. After comparison with the original design, an advanced scheme is achieved which has provided the technical support in the compressor design. Now the compressor is normally operating.更多还原