【作者】 谢敬华；

【导师】 钟掘；

【作者基本信息】 中南大学 ， 机械工程， 2014， 博士

【摘要】 摘要：液压系统中的流体管道是承载物质流、能量流、信息流的重要系统元件之一,管道系统的设计一定程度上影响着液控系统的功能。在盾构掘进液压系统中,负载的突变、工况的变换会引起系统中流体状态突变,从而产生流体压力脉动。流体压力脉动通过流固耦合诱发管道振动,造成噪声污染,甚至导致管道破坏或机器失效。决定液压管道系统动态特性的一个重要因素是复杂的流固耦合作用,而盾构液压系统中管道长、油压高、工况与载荷突变,耦合效果十分复杂,传统方法预测的液压管道动态特性存在较大误差(特别是管道长而约束弱时),由此设计的管路系统潜藏安全隐患。为使盾构机获得优异的动力传递性能,深入研究流固耦合长管道效应是十分必要的。盾构液压系统的管道长可达100余米,流固耦合长管道效应十分突出。长管道效应由管道沿程压力损失/能量损耗、油击、管道振动等多种作用综合形成。在管道效应的三项构成中,显然流体和管道都不可能孤立起作用,必然是耦合的结果。长管道流固耦合效应严重影响管道输流特性和液压系统控制特性,流固耦合也是抑制流体振荡和管道振动必须计入的基本要素,因此流固耦合振动的研究是此类管道设计与运行控制中的核心。为此,本文开展了以下研究并取得了一些相关的新认识：1)长管道液控系统动态响应特性研究。盾构液压管道长,系统沿程压力损失大、响应滞后、能量损耗大,为改善响应速度问题,本论文研究并提出了考虑长管道耦合效应作用下阀控系统动态性能影响因素建模方法,通过仿真分析查明了管道结构参数和蓄能器参数对系统的影响规律；在此基础上开展了以降低能耗为目标的实验研究,得到了相关参数的量化关系。以管道压力损失最小为目标,进行了管道结构优化设计,确立了基于压力损失的管道结构参数域空间。2)液压长管道流固耦合振动特性研究。根据波动理论建立了单跨管道传递矩阵。针对盾构机液压系统中管道长、多跨的特点,通过位移边界条件、波动传递理论及流体连续性理论建立多跨管道场传递矩阵,据此可递推多跨管道任意跨中的场传递矩阵。基于这种认识,论文提出了可适用于多跨输流管道复杂管道系统的递推建模方法,该方法可快速计算系统中任意跨的场传递矩阵,为分析多跨复杂管道系统提供了较好的理论基础和方法。建立了长管道振动判据；提供了基于避免耦合振动的固支数计算方法,进一步形成了固支数优化计算模型,克服了以往依据经验选择固支数的不足。3)设计与搭建盾构机长管道液压实验台。自主设计、开发了专用研究实验台。实验台主要功能有：模拟盾构推进系统的液压长管道系统工作状态；实验校验及修正所建立的关于流固耦合长管道效应的数学模型；适用于开展在不同管道长度、不同管道约束状况、不同外部负载、非稳态运行情况下带长管道阀控系统动态和静态特征的实验研究。为能实现各种功能,机电液集成设计中提出并实现了若干项有特色的技术模块：负载和动力部分设计成对顶油缸装置,形成大负载的模拟功能；多跨输流长管道系统设计成蛇形排列、立柱可移动、固支可拆卸的形式,便于有限空间内布置长管道、灵活改变管道结构参数；控制系统应用模块化和参数化理念开发,使实验过程能按预设程序全自动完成；通过配置合理的传感器、数据采集系统及振动分析系统,发明了一种液压长管系统振动效应测试方法及装置。4)液压长管道系统的振动实验研究。对液压长管道系统分别进行了实验模态分析、工作振型测试和激励源频率特性测试,试验表明：液压长直管道固有频率在低频段较为密集；管道跨距对模态参数表现出规律性的影响：跨距越大,管道的梁模型特征越显著,固有频率越低,容易使管道结构在动负载状态下与外界激励发生共振；通过增加支撑的方法可以降低管道跨距,显著提高管道的固有频率,但其导致振型变化的规律难以确定,不利于进行振动抑制。本论文研究工作的创新性体现在：1)针对盾构液压阀控系统管道长、液压系统响应复杂、滞后问题突出的特点,本论文通过仿真与实验研究了管道结构参数调整和蓄能器调节对响应滞后的影响规律,并提出了以压力损失最小为目标的节能优化设计方法。2)建立了简支输流管道流固耦合传递矩阵模型,提出了多跨输流管道传递矩阵递推建模方法与长管道振动判据,进一步形成了固支数计算模型,并结合仿真分析,凝炼了固支数优化的理论基础和原则。3)构建液压长管道实验台的创新点：a.利用大推力可变负载的对顶油缸装置实现70吨动力和多种负载加载状态(突变负载、程控负载和惯性负载)；b.研制了多组合液压长管系振动效应测试装置,实现了盾构拟实复杂管道系统振动的测试。上述研究成果为液压长管道流固耦合特性研究、管道结构参数优化匹配提供了理论基础、关键技术与实验平台支持。更多还原

【Abstract】 Abstract:Fluid pipe is one of the most important components of hydraulic system which works as to carry material flow, energy flow and information flow. The design of the pipeline system, to some extent, affects the function of the hydraulic control system.As for the hydraulic system of the shield tunneling machine, the change of sudden load or operating conditions can cause mutation in the fluid state of the system, resulting in fluid pressure pulsation which induces pipe vi-bration by the fluid-structure interaction, generates noise pollution, and even leads to pipeline damage or failure of the machine. The complex fluid-structure interaction effect is one of the most important factors which de-termine the dynamic characteristics of the hydraulic piping system. More-over, taking into account the long length pipeline, high oil-pressure and rapid mutation of work conditions and load, coupling effect is very com-plicated in the hydraulic system of the shield tunneling machine. With re-gard to the complex fluid-structure interaction, the conventional dynamic performance analysis of hydraulic pipeline system analysis is insufficient. In a word, the pipeline dynamic characteristics forecasted by the traditional methods have much error, especially when the pipeline is long and weakly constrained. It makes the safety of piping system greatly reduced which is designed according to the traditional method. To get excellent power trans-mission performance, in-depth study of long pipeline effect of the shield machine based on fluid-structure interaction is very necessary.With length of pipeline could be up to100meters, fluid-structure inter-action effect is very prominent in the long pipeline hydraulic system of shield machine. The formation of long pipeline effect of the shield machine is the comprehensive result of the oil strike, the pressure loss or energy loss along long pipeline, the pipeline vibration induced by fluid-structure inter-action. It is clear the fluid and the pipe cannot work individually regarding the three components of long pipeline effect. Long pipeline FSI effects se-riously affect flow characteristics of pipeline and control characteristics of hydraulic system, and fluid-structure interaction is one of the basic ele- ments which must be included in to inhibit fluid oscillations and pipe vi-bration, so the study of vibration of the fluid-structure interaction is the key to the design and operational control of such pipeline system. Around this core, this dissertation carried out the following studies and made some rel-evant new knowledge:1. Study of Dynamic Response Characteristics of the Long Pipeline Hydraulic Control System. The pipeline of shield hydraulic system is long, and it causes the high loss of pressure and energy, even causes re-sponse lag. To improve the speed of response, this dissertation proposed the modeling method of the impact of factors on the dynamic performance of shield hydraulic control system in which long pipe interaction effect was considered and conducted simulation respectively from the perspective of the pipeline structure parameters and the accumulator, then influence law of the two on hydraulic system was pointed out; furthermore, the quantita-tive relationship was obtained by the corresponding experimental study. On the condition of minimal loss of pipeline pressure, this dissertation opti-mized the pipeline structure design. In this way the parametric space of pipeline structure based on pressure loss was established.2. Study of Vibration Characteristics resulted from Fluid-Struc-ture Interaction Effect in Long Hydraulic Pipeline. A single span pipe-line transfer matrix was established according to the wave theory. For the characteristics of long length and multi-span attached to the hydraulic pipe-line of shield machine, multi-span pipeline field transfer matrix was finally derived from displacement boundary conditions, fluctuation transmission theory and continuity theory of fluid. Accordingly, the field transfer matrix of any cross could be recursive. Based on this understanding, a recursive method was put forward to model fluid-structure interaction in long multi-span pipeline. The method could quickly deduce the field transfer matrix of any cross, which would provide a good theoretical basis and methods for the analysis of complex multi-span pipeline system. A long pipe vibra-tion criterion was established. Based on avoiding the fluid-structure inter-action resonance, a calculation method of counts of clamped support and following optimization model were provided with which the shortage of selecting counts of clamped support based on experience in the past has been overcome.3. Design and Construction of Hydraulic Experimental Table of Long Pipeline. A dedicated research experimental table was independently designed and developed. The main functions of the table are as follows:to simulate the hydraulic behavior of shield propulsion system; to calibrate and correct the mathematical model related to fluid-structure interaction effect in long pipeline hydraulic system; to study the dynamic and static characteristics of valve control system with long pipe under the condition of different length of pipe, different constraints situation, different external load, non-steady-state operation. In order to achieve a variety of functions, hydraulic integration design proposed and implemented a number of dis-tinctive technology modules:paired cylinders device were designed to act as power and load respectively, with which large load could be applied in experiments; serpentine arrangement, movable columns and detachable support applied to the design of long multi-span pipeline system facilitate the layout of long pipeline in limited space and improve the flexibility of changing the structural parameters of pipeline; control system was devel-oped by the concept of modularization and parameterization, so that the experiment could be completed automatically according to preset programs; By configuring reasonable sensors, data acquisition system, and vibration analysis system, a test method and apparatus was invented to study vibra-tion effects in hydraulic system with long pipeline4. Experimental Study of Vibration in Hydraulic System with Long Pipeline. Modal analysis, operating deflection test and excitation source frequency characteristic test were carried out on the hydraulic experi-mental table with long pipeline. The tests showed:firstly, the natural fre-quency of the hydraulic long-straight pipeline was densely distributed mainly in the low frequency; secondly, pipeline span regularly affected the modal parameters. With the span increased, beam model features of pipe-line became obvious and the natural frequencies of pipeline were reduced which made it easy to resonance with the external excitation for pipeline under the dynamic load; in addition, pipeline span could be reduced and the natural frequencies of pipeline could be significantly increased by in- creasing the number of supports, but this would make the regularity of vi-bration mode change hard to be discovered which was not conducive for vibration suppression.The innovation of this dissertation is summarized as follows:1. Aiming at the features of valve control hydraulic system of shield machine:long pipeline, sophisticated response of hydraulic system and ob-vious response lag, this dissertation studied the influence law of the pipe-line structural parameters and accumulator on response lag by the ways of simulation and experiment, and proposed a Energy saving optimization method with the objective of minimizing pressure loss.2. Based on the established transfer matrix model of fluid structure in-teraction effect in conveying fluid pipes simply supported, a recursive transfer matrix modeling method for multi-span conveying fluid pipes and a long pipe vibration criteria were proposed. Furthermore, a calculation model of counts of clamped support was formed. Combining with simula-tion analysis, this dissertation tried to conclude some basic theories and principles for optimizing the counts of clamped support.3. The innovation of experimental table could be reflected in:a) the design of a large thrust device consisting of two opposite oil cylinders which could simulate70tons of power and a variety of load (mutation load, program-controlled load and inertia load); b) the development of the test sets which would be competent for vibration effect test of the visual reality complex piping system composed of multi-combination pipes.The above research results provided some basic theories, key technol-ogy and experimental platform support for study on the characteristics of long hydraulic pipeline included in fluid structure interaction effect and optimization of structure parameters of pipeline system.更多还原