离心压缩系统反转动力学特性研究与分析

发布时间：2018-03-03 07:54

本文选题：离心压缩机　切入点：反转　出处：《上海交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：当前随着设计、制造技术的进步,在节能减排的要求下,离心式压缩机向着大型化、高压比的趋势发展。大型多级离心压缩机组的运行必然会出现新的系统运行问题,如系统调控、转子动力学、流动部件匹配和机组启动、停机控制等。由于大型流动系统中,流动管道多、容器大,系统惯性大,一般难以在短时间内进行流动参数的调节。在实际生产运行过程中,由于工艺的需要,流动系统中往往储存着大量高压气体。一旦出现断电情况,压缩机组会因失去驱动力而停机。在这种情况下,压缩机组出口段的气体压力会因为远大于进口段的压力,而从机组的出口段通过压缩内部流向入口段,产生系统逆流。气体的逆向流动在压缩机内部会产生反向的转动力矩,使机组转速迅速下降,在该转动力矩克服转子的惯性力矩与气动阻力矩后,会进一步发生转子反转现象。压缩机组的反转会破坏轴承和级间密封,严重影响企业的正常生产秩序。因此,有必要对现有大型机组进行反转研究,提出有效的防反转策略。针对实际企业发生的反转事故,本文对离心压缩系统进行了简化,建立离心风机单转子流动压缩系统。该系统包括管道进出口阀门、出口气罐等。实验测试基于LABVIEW软件建立多通道实时数据采集系统,可以得到离心风机前后管道压力、流量与转速。实验研究了风机转子在惰走情况下气动和摩擦阻力对转速的影响,建立了考虑工质气动力矩、轴承摩擦力矩的转子转速变化模型。对实验转速与根据转子转速变化模型的到的计算转速进行对比,验证了转子转速变化模型的准确性。对离心叶轮的结构分步进行简化得到转动惯量的表达式,根据简化固定容器的充放气模型得到逆流流量的变化规律,并分析了逆流阀门的调节对逆流流动特性的影响。对比相同转速变化范围内,正反转情况下作用于转子的扭矩、功率规律,说明反转对离心转子破坏的可能性加大。根据离心风机单转子实验和理论分析结果,对某石化企业的乙烯装置裂解气离心压缩机组发生反转情况下各段进出口流动参数进行了分析,结合流动压缩系统模型建立了由多级离心叶轮转动惯量、初始转速和防喘阀开度影响下的逆流驱动转子转速变化模型。将该模型应用于实际大型多级离心压缩机组的转子反转动力学分析中,可以得到抑制其反转的运转参数。本文所建立的理论模型可以通过实验结果和运行数据进行验证,可为大型离心压缩机的防反转提供策略。
[Abstract]:At present, with the development of design and manufacturing technology, under the requirement of energy saving and emission reduction, the centrifugal compressor is developing towards a large scale and high pressure ratio. Such as system control, rotor dynamics, flow component matching, unit start-up, shutdown control, etc. In large flow systems, there are many flowing pipes, large containers, and large inertia of the system. Generally, it is difficult to adjust the flow parameters in a short period of time. In the actual operation process, due to the need of the process, a large number of high pressure gases are often stored in the flow system. The compressor unit will be shut down because of the loss of driving force. In this case, the gas pressure at the outlet section of the compressor unit will be much greater than the pressure in the inlet section, and the outlet section of the compressor unit will flow from the outlet section of the unit to the inlet section through the compression inside, The reverse flow of gas in the compressor will produce reverse rotation torque, which will cause the unit speed to drop rapidly. After the moment overcomes the inertia moment and aerodynamic resistance moment of the rotor, The reverse of the compressor unit will destroy the bearing and the seal between stages, which will seriously affect the normal production order of the enterprise. Therefore, it is necessary to carry out reverse research on the existing large units. An effective anti-inversion strategy is put forward. The centrifugal compression system is simplified and the single rotor flow compression system of centrifugal fan is established. The system includes pipeline inlet and outlet valve. The multi-channel real-time data acquisition system based on LABVIEW software can be established to obtain the pressure of the front and rear pipes of the centrifugal fan. The effects of aerodynamic and friction resistance on the speed of the fan rotor under the condition of idling walk are studied experimentally, and the aerodynamic moment of the fan rotor considering the working fluid is established. The rotor speed variation model of bearing friction torque. The comparison between the experimental speed and the calculated speed according to the rotor speed change model is carried out. The accuracy of rotor speed change model is verified. The formula of moment of inertia is obtained by simplifying the structure of centrifugal impeller, and the variation law of countercurrent flow is obtained according to the simplified gas filling and discharging model of fixed vessel. The effect of countercurrent valve regulation on countercurrent flow characteristics is analyzed. Compared with the torque and power law of rotor acting on the rotor under positive and reverse rotating speed in the same speed range, According to the results of single rotor experiment and theoretical analysis of centrifugal fan, In this paper, the inlet and outlet flow parameters of cracking gas centrifugal compressor unit in a petrochemical enterprise are analyzed, and the rotational inertia of multi-stage centrifugal impeller is established by combining with the flow compression system model. The rotor speed change model of countercurrent driven rotor under the influence of initial speed and the opening of anti-surge valve is applied to the rotor inversion dynamics analysis of large scale multi-stage centrifugal compressor unit. The theoretical model established in this paper can be verified by experimental results and operation data and can provide a strategy for anti-inversion of large centrifugal compressors.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH452

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