【作者】 袁林；

【导师】 丁刚；

【作者基本信息】 哈尔滨工业大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 减压阀是蒸汽系统中的重要设备,国产导控型减压阀在使用过程中存在着调压不稳定、使用寿命短、故障率高及易产生振动与噪声等问题。本文以某款导控型减压阀为基础,对其进行了仿真分析及优化。主要内容包括:减压阀系统仿真及特性优化、减压阀流场仿真及振动与噪声分析、减压阀膜片的疲劳寿命预测。针对减压阀调压不稳定问题,本文在分析减压阀工作原理的基础之上,建立减压阀系统的数学模型,并在Simulink平台上对其进行了系统仿真与分析。通过总结蒸汽系统中对减压阀静、动态特性的需求,对不同结构参数对减压阀静、动态特性的影响进行仿真分析,并从中选取可行优化参数,制定评价函数,采用多目标粒子群算法对减压阀的稳定性、压力特性和流量特性进行了优化,经过与优化前的压力输出曲线对比,验证了特性优化的可行性。为研究减压阀振动与噪声问题,需对减压阀内部流场进行仿真分析。本文首先对减压阀主阀腔的内部流场进行了稳态仿真,在分析稳态流场基本特征的基础上,采用动网格技术,对主阀腔内部流场进行瞬态仿真,得到更逼近真实情况下的主阀腔内部流场信息,分析了诱发振动与噪声的原因。并通过对流场关键点位置进行监测,获取了压力脉动数据。同时,对减压阀结构模态和声腔模态进行有限元计算,分别得到了结构和声腔的模态频率和振型。将获取的压力脉动数据进行频谱转化,与模态频率进行对比,分析了可能出现结构共振和声腔共鸣的频率及振型。对于减压阀使用过程中最容易失效的金属膜片,本文对其进行了疲劳寿命分析。采用有限元方法,分析了热-结构耦合情况下,膜片工作过程中的应力分布。针对实际产品中采用一层膜片和两层膜片两种方案,采用名义应力疲劳寿命分析方法和线性累积损伤理论,结合已有文献中的疲劳寿命曲线,在进行平均应力修正的基础上,对两种方案的膜片疲劳寿命进行了预测,并与减压阀设计使用寿命进行了对比校核。通过以上研究,本文为导控型减压阀的研制提供了理论支撑,并为后续减压阀产品的改进和系列化提供了参考。更多还原

【Abstract】 Pressure relief valve is an important equipment in the steam system.But many problems occur in the use of domestic pilot pressure relief valve such as instability,short life,high failure rate,vibration and noise.In this dissertation,based on a widely used pilot pressure relief valve,simulation and optimization work is carried out.The contents include: system simulation of pilot pressure relief valve,characteristics optimization,numerical simulation of the pressure valve flow,and fatigue life prediction of the diaphragm.Based on the analysis of working principle of the pressure relief valve,the mathematical model of the valve system is established,and the system simulation and analysis are carried out on the platform of Simulink.By analyzing the demands of static and dynamic characteristics of pressure relief valve in the steam system,the influence of different structural parameters on the static and dynamic characteristics of the pressure relief valve is simulated and the feasible parameters are selected.By setting the evaluation function,multi-objective particle swarm algorithm is used to optimize the characteristics.After comparing with the output pressure curve without optimization,the feasibility of the optimization is verified.In order to study the vibration and noise of the pressure relief valve,it is necessary to simulate the flow of steam inside the pressure relief valve.Based on the static simulation of the internal flow of the main valve chamber of the pressure relief valve,the dynamic grid is used to simulate the internal flow of the main valve chamber in transient way.The internal flow information is analyzed and the reason of induced vibration and noise is studied.The pressure pulsation data is obtained by monitoring the key position of the flow field.At the same time,the finite element simulation of the structural modals and acoustic modes of the pressure relief valve is carried out,and the modal frequency and modal modes of the structure and the vocal cavity are obtained respectively.The obtained pressure pulsation data is transformed into frequency spectrum and compared with the frequencies of structural modals and acoustic modals.The possible resonant frequency is analyzed.For the most vulnerable metal diaphragm during the use of the pressure relief valve,the fatigue life study is carried out in this dissertation.The finite element method is used to analyze the heat and structural coupling problem and the stress distribution on the diaphragm.Facing the problem of using one diaphragm or two diaphragms in the product,the nominal stress fatigue life analysis method and the linear cumulative fatigue damage theory are used to compute the fatigue life of the two cases.And the fatigue life of the two cases is also predicted and compared with the design life of the pressure relief valve.To conclude,this dissertation provides the theoretical support for the development of the pilot relief valve,and also provides a reference for the improvement and serialization of the pressure relief valve products.更多还原