大型离心式压缩机叶轮静动载荷的分析与研究

发布时间：2018-01-05 21:15

本文关键词：大型离心式压缩机叶轮静动载荷的分析与研究　出处：《东北大学》2013年硕士论文　论文类型：学位论文

【摘要】：随着工业化的不断加强,人类社会对氧气、氮气和氩气等工业气体的需求迅速增加,导致了空气分离装备的不断大型化。而大型离心空气压缩机是大型空分气离装备的核心设备,其性能的好坏对整个空分装备的安全可靠运行都至关重要。叶轮是离心压缩机的关键部件,叶轮承受的载荷主要包括旋转离心力、轴系振动力和气动力。离心力会使叶片产生较大的静应力,气动力及轴系振动力将引起叶轮叶片的振动,从而使叶片产生较大的交变应力,导致叶轮叶片的疲劳破坏。因此,叶片静动态载荷的确定成为叶轮设计的关健问题之一。本文依托973课题的研究背景,以制氧系统中的离心压缩机为研究对象,借助CFD数值模拟技术研究了离心压缩机叶轮的静动态载荷。基于单向流固耦合方法分析了压缩机工作过程中的气动载荷及离心载荷对叶轮模态参数的影响,以及空气入口参数对叶轮气动载荷的影响；并利用非定常流动理论,研究了叶片气动载荷的瞬态特性。具体完成如下几个内容。(1)利用CFX软件对叶轮内部流场进行求解,并将计算的结果施加在叶轮表面,利用预应力模态分析法,研究了离心力和气动载荷对叶轮模态参数的影响规律。结果表明,随着阶数的升高,预应力对模态频率的影响变大,其中气动载荷的影响较小。(2)通过调整理想气体与理想水蒸气的比例及改变进气温度,研究了空气相对湿度及进气温度对叶轮表面气动载荷的影响规律。分析结果表明,叶轮表面气动载荷随相对湿度的升高而增大,相对湿度每升高10%,气动载荷增大200Pa左右；叶轮表面气动载荷随温度的升高而升高,温度每升高10℃,气动载荷增大2000Pa左右。(3)对叶轮内部流场进行了非定常计算,得到了在静止导叶下叶轮表面气动载荷随时间的变化规律,分析了导叶与叶轮之前的非定常干涉机理；分析了非谐设计导叶对叶轮内部非定常流动影响,揭示了非谐设计导叶对叶轮表面气动载荷的影响规律；结果表明,气体激振频率与导叶个数和叶轮转速有关而与进气温度无关；非谐设计导叶可以降低气体的激振频率,进而使频率等于导叶个数与转速乘积的激励载荷的幅值减小,但同时使气体低阶激励载荷的幅值增大。
[Abstract]:With the development of industrialization of human society to strengthen, oxygen, nitrogen and argon and other industrial gas demand increased rapidly, leading to a large scale air separation equipment. But the centrifugal air compressor is large large air separation gas from the core equipment, are vital to the safe and reliable operation of the performance of the whole equipment is divided into empty. The impeller is the key component of centrifugal compressor impeller, including load bearing rotating centrifugal force and aerodynamic force. The vibration of shafting, the centrifugal force will make the blade static stress is large, the aerodynamic and shafting vibration will cause the vibration of the impeller blades, and the blades generate high alternating stress, cause fatigue failure of the impeller blade the static and dynamic load. Therefore, the leaves determined to become one of the Guan Jian problem of impeller design. This paper based on the research background of the subject 973, the oxygen system of centrifugal compressor As the research object, by means of static and dynamic loads on the centrifugal compressor impeller CFD numerical simulation technology. The unidirectional flow solid coupling method of compressor working process of pneumatic impact load and centrifugal force on the impeller based on modal parameters, and air entrance parameters affect on dynamic load of impeller gas; and the use of non steady flow theory and transient characteristics of blade aerodynamic load. Complete the following content. (1) to solve the impeller internal flow by using the CFX software, and the calculation results were applied in the impeller surface, using the method of prestressed modal, influence of aerodynamic load on the modal parameters of the impeller of centrifugal force. The results showed that with the elevation of order, effect of prestress on the modal frequency of the larger, the smaller influence of aerodynamic load. (2) the proportion of adjustment and change of ideal gas and water vapor into the ideal Study on the gas temperature, air relative humidity and air temperature on the impeller surface aerodynamic effect of load. The analysis results show that the impeller surface aerodynamic load increases with the increase of relative humidity, relative humidity increases every 10%, the aerodynamic load increases about 200Pa; the surface of impeller aerodynamic load increases with the increase of temperature, temperature for every increase of 10 degrees, the aerodynamic load increases about 2000Pa. (3) the internal flow field of the impeller of the unsteady calculation, obtained in the static load variation with time by impeller surface gas leaves, analyzed before the guide vane and the impeller of the unsteady interference mechanism; analysis of non harmonic design guide leaves on the impeller internal unsteady flow effect, reveals the non harmonic design of vanes on the impeller surface aerodynamic effect of load; the results show that the gas excitation frequency and guide vanes and impeller speed without closing and the intake air temperature; non Harmonic design of guide vane can reduce the excitation frequency of gas, and then reduce the amplitude of the excitation load with the frequency equal to the number and speed of the guide vane, but at the same time, increase the amplitude of the low order excitation load of the gas.

【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH452

【参考文献】