【作者】 王杨；

【导师】 冀春俊；

【作者基本信息】 大连理工大学 ， 流体机械及工程， 2008， 硕士

【摘要】 离心压缩机在我国国民经济建设中数量多,应用广,在石油化工、冶金业等领域发挥着极其重要的作用。在大多数情况下,离心压缩机在整个运行系统的工作过程中扮演着核心角色,压缩机的平稳运行是整个生产线安全生产的重要保障。离心压缩机在实际运行中经常会在非设计工况下运转而伴随着旋转失速等非稳态流的发生,旋转失速等现象的存在对离心压缩机的稳定运行构成极大的威胁,很多时候它们的存在给机组的安全运行带来严重的危害甚至导致灾难性的后果。所以,对压缩机旋转失速机理的认识和研究,进而实现对其进行控制,对于提高其性能和可靠性具有重要意义。本文针对实际运行过程中某压缩机首级叶轮叶片断裂的问题,以该机组低压缸首级部分内部流场为研究对象,利用CFD软件NUMECA搭建一个基于完整真实的三维几何结构的离心压缩机内部流场数值分析平台,选用实际运行工况进行计算,使用三维造型软件Pro/E建立整个首级流场的物理模型,计算分析了包括进气室、进气导叶和首级叶轮及无叶扩压器在内的完整流场,发现由于进气室和进口导叶的设计可能存在一定的问题,叶轮进口的来流是不均匀的,导致首级叶轮前的流场畸变,从而诱发压缩机首级叶轮失速,引起叶轮内部的压力场在较大范围内变化,进一步的力学分析结果表明这种压力脉动可能是造成叶轮叶片振动、疲劳断裂的原因,通过进行非定常流动计算,动态模拟了旋转失速的发展传播过程,得到了比较真实的旋转失速的压力脉动情况,以此更加直观地证明了旋转失速是导致叶轮叶片疲劳破坏的直接原因,为工厂实际问题的解决提供了有利的科学依据。更多还原

【Abstract】 Centrifugal compressors play an important role in national economy construction for its broad usage in many important industries, such as the petrochemical industry, metallurgy, etc. In many cases, centrifugal compressors are the key equipments in the whole cooperation. The smooth operations of the centrifugal compressors are vital to the production lines. One particular phenomenon that threatens the safe running of the compressor is the rotating stall in the compressor. In many cases, rotating stall had caused great damages with serious consequence. The study of the rotating stall is of great importance for the prevention of the rotating stall in the design stage or the control of the rotating stall during the operation.The fracture problem of the first stage impeller blades in one centrifugal compressor was studied in this thesis by analysis the flow field in the inlet camber and the first stage. The numerical analytic platform was based on the CFD commercial software NUMECA and the real 3-D geometry model of the compressor. The boundary condition was specified by the actual operating parameters. Simulation results indicate that the flow distortion at the impeller inlet is induced by the poor design of the inlet camber and the inlet guide vane. The flow distortion upstream of the impeller inlet excitateds the rotating stall so that the pressure field oscillated violently. Based on the simulation results of the pressure field, further mechanic analysis proved that the vibration and fracture failure of the impeller blades is most likely caused by this pressure fluctuation. Unsteady flow simulation was carried out and the propagation and development of the rotating stall cell was observed clearly. The actual pressure fluctuation on the blade surface was obtained for accurate mechanic analysis. The study may provide a guideline in solving the fracture problem of the impeller blades.更多还原