【作者】 安延涛；

【导师】 王勇；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2012， 博士

【摘要】 调节阀广泛应用于火力发电、核电、化工等流体控制场合,是物料或能量供给系统中不可缺少的重要组成部分。在钢厂的循环发电工程中,各钢厂利用公称直径d≥200mm的大型调节阀对混合煤气进行压力控制。调节阀由于长时间的运行磨损、设备的自然老化以及人为损坏等因素影响,故障时有发生,将导致发电设备停机,不仅对电网造成冲击,而且造成巨大的经济损失。大型压力调节阀的动态分析和故障诊断已成为钢厂循环发电工程中的一个关键技术问题。针对钢厂循环发电工程中大型压力调节阀故障及检测问题,本文进行了如下的研究工作：系统研究了大型压力调节阀动态分析及故障检测的有关问题。提出了大型压力调节阀在减振、节能、降噪、故障检测及定位研究中仍需解决的问题,指出可根据调节阀的结构特点研究减振,根据内部流场研究节能及降噪,以及根据故障动态特征研究检测及定位。根据调节阀动态分析及故障检测的相关理论,研究了调节阀泄漏和堵塞故障的检测机理,提出了混合煤气的质量流函数,建立了检测混合煤气质量流的数学模型。此外,在故障定位研究中,引入质量流梯度,分析了泄漏和堵塞故障的定位机理,为后续章节的进一步研究提供理论基础。研究了大型压力调节阀的动态模拟及优化。建立了大型压力调节阀的三维实体模型,并对其进行了模态分析,结果表明,调节阀的固有频率总体上随相对开度的增加而较小,在此基础上,提出了基于扩展主动变刚度的调节阀振动控制的方法。建立了调节阀的流道模型,采用混合煤气为介质分析了调节阀的流量特性、压差-流量和开度-压差特性。分析了调节阀内部流场漩涡产生的原因,并通过流道的优化,消除阀座处的漩涡,减小阀出口处的漩涡。讨论了调节阀噪声产生的原因及影响因素。针对噪声控制,提出了基于变节流面迂回通路的调节阀噪声治理的方法,设计了带锥度的多孔式套筒。分析了多孔式套筒孔的大小和数量对降噪的影响。结果表明,采用有锥度的多孔式套筒不仅消除了阀出口下方的大漩涡、减小了左侧腔的漩涡,而且较普通的多孔式套筒降噪效果更明显。研究了调节阀泄漏时的动态特征及检测、定位方法。建立了调节阀入口、出口、阀杆和阀体阀盖处泄漏的三维模型及其流道模型,对不同泄漏故障进行了模态分析、流场分析。结果表明,泄漏故障降低大部分阶次的固有频率,调节阀的入口、出口泄漏的流量特性曲线较无故障时有轻微下凹,使其流量特性减弱。针对泄漏故障提出了泄漏口流量特性,入口、出口泄漏口流量特性曲线类似于下降的线性特性曲线,阀盖泄漏口和阀杆泄漏口的流量特性曲线类似于向下倾斜的正弦曲线。出现泄漏故障时为减小能源损失,在保证阀后压力稳定的情况下应尽量提升阀前压力。分析了泄漏口大小、数量对调节阀压差-流量,以及泄漏故障对调节阀噪声的影响。根据调节阀泄漏故障内部流场的动态特征,研究了调节阀泄漏故障的检测及定位,提出了采用质量流进行泄漏检测,双质量流差进行泄漏定位的方法,并总结出相应的泄漏定位判定表。研究了调节阀堵塞时的动态特征及检测、定位方法。建立了调节阀入口、出口及阀体内堵塞的三维实体模型,并通过模态分析得到阀入口堵塞和阀体内堵塞降低调节阀的固有频率,阀出口堵塞提高调节阀的固有频率。在三维实体模型的基础上,建立了各堵塞故障的流道模型,分析其内部流场,结果表明,堵塞故障使流量特性曲线凸起,流量减小,需要增加开度或压差才能达到预定的流量。分析了堵塞物的大小及数量对调节阀流场的影响,得到流量受出口堵塞的影响大于入口堵塞,随出口堵塞物的增大急剧减小,同时研究了堵塞故障对调节阀噪声的影响。根据调节阀堵塞故障内部流场的动态特征,研究了调节阀堵塞故障时的检测及定位,提出了采用质量流波动检测堵塞,同样采用双质量流差方法进行堵塞定位,并总结出相应的堵塞定位判定表。构建了调节阀动力学性能及质量流检测试验系统。对调节阀进行了模态实验和质量流检测试验,以及调节阀故障诊断系统的设计。通过调节阀的模态实验,验证了调节阀建模的准确性以及仿真数据的可信性。通过质量流检测试验,证明混合煤气质量流的数学模型可准确的反映并监测系统质量流的变化,以及调节阀故障诊断系统的可行性。更多还原

【Abstract】 The control valve is widely used in thermal power, nuclear, chemical and other fluid control occasions, it is the indispensable and important component in materials or energy supply system. Steel mills using waste gas in combined cycle power project, steel mills use the nominal diameter≥200mm of large control valve to control pressure of the mixed gas. With the long time running, the natural aging of the equipment, human damage and other reasons, the fault of control valve occurs frequently, it will lead to the shutdown of power generation equipment, and it also caused a huge economic losses.Therefore, large pressure control valve dynamic analysis and fault diagnosis becomes a key technical problem of the combined cycle power plants. The main research contents of this paper are as follows.The related problem of the dynamic performance and fault detection for large-scale pressure control valve were studied. The problem of needing to solve for vibration control, energy conservation, noise control, fault detection and localization were discussed, and pointed out that according to the structural characteristics to research vibration reduction, according to the internal flow field to research energy saving and noise reduction, and according to the dynamic characteristics to study the fault detection and localizationDynamic analysis and fault detection theory of valve were introduced. The fault detection mechanism of the leakage and blockage were studied, mass flow functionand the mathematical model of mixed gas mass flow was established. In fault location, the mass flow gradient was introduced, and the fault location mechanism of the leakage and blockage were studied, and it provided a theoretical basis for the further study of the later chapters.The dynamic analysis and optimization of large-scale pressure control valve were researched. The3D solid model of large-scale pressure control valve was established. The modal analysis results showed, over all, with opening increasing, frequency was reduced. On this basis, the expansion of semi-active variable stiffness was proposed. Then the flow model was established, the flow characteristics, pressure-flow and opening-pressure properties were studied by mixed gas. The causes of valve internal flow field whirlpool were analyzed. Through the optimization, the whirlpool of seat was eliminated, and the outlet of the whirlpool was reduced. Proposing variable throttling surface Circuitous path for noise reduction by studying noise control mechanism, and the influence of the size and number of the porous sleeve for noise reduction were analyzed. The results showed that it not only eliminated the large whirlpool in the bottom of the valve outlet, reduced the swirl of the left side of the cavity, it was more apparent than common porous sleeve in noise reduction.The dynamic characteristics and leakage fault detection and location method of the control valve were researched. The3D model of valve inlet leakage, valve outlet leakage, valve stem leakage, valve cover leakage and their flow models were established. The modal analysis and flow analysis of the different leakage faults were studied. The results showed that the leakage fault reduced the order of the natural frequency, flow characteristics curve of inlet leakage and outlet leakage were slight concave than trouble-free, quick opening were weakened. The leakage point flow characteristics were proposed by leakage fault, and pointed out that flow characteristic curve of inlet leakage point and outlet leakage point were similar to the decline of linear curve. The valve stem leakage point and valve cover leakage point were similar to the decline of sine curve. In order to ensure the stable after pressure, the valve should be as far as possible maximize the before pressure. The influence of the leak port size and number for differential pressure-flow of valve, and leakage faults for noise distribution were researched. According to the dynamic characteristics of the valve leakage, leakage fault detection and localization were studied. The method of mass flow leak detection and double mass flow leak location were proposed. The leak location table was made through simulation experiments.The dynamic characteristics and blockage fault detection and location method of the control valve were researched. The three-dimensional model of valve inlet blockage, valve outlet blockage and valve body blockage were established. The modal analysis showed that the valve inlet blockage and valve body blockage reduced the natural frequency, and valve outlet blockage increased the natural frequency of valve system. On the basis of three-dimensional solid model, the blockage fault flow models were established. The internal flow fields were analyzed. The results showed that flow characteristics curve of blockage were slight convex, quick opening were raised and the flow reduced. In order to achieve a predetermined flow rate should to increase opening or pressure. The influence of the block size and number for flow field were researched, got the influence of outlet blockage was bigger than inlet blockage in flow field, the flow sharply reduced with obstruction increased. The influences of the blockage faults for noise distribution were researched. According to the dynamic characteristics of the valve blockage, blockage fault detection and localization were studied. The method of mass flow leak detection and double mass flow block location were also proposed. The block location table was made through simulation experiments.The experiment system of dynamic performance and mass flow detection were constructed. Modal experiments and mass flow detection experiments were done, and valve fault detection system was designed. Through the modal experiment, the accuracy and credibility of the control valve modeling and simulation data for the previous section were verified. Through the mass flow detection experiments, they showed that can accurately reflected and monitored the change of the mass flow for the system, and the feasibility for fault diagnosis system.更多还原