【作者】 王保明；

【导师】 李意民；

【作者基本信息】 中国矿业大学 ， 流体力学， 2011， 博士

【摘要】 液压支架作为采煤工作面的主要安全支护设备,对于建设高产高效的本安化矿井具有决定性的意义,其关键部件的结构、性能及整体动态性能的好坏直接影响着整个综采工作面的可靠性及安全性。由于缺乏相应的理论支撑以及实验手段支持,对于液压支架关键部件(液控单向阀及安全阀)、液压支架系统内部流场、流动规律及各自的动态特性研究不够充分。本文针对工作面常用的ZY4000/09/21型液压支架,进行了理论分析、计算研究、FLUENT和ABAQUS数值模拟、Matlab/Simulink仿真及实验研究,全方位的分析了影响液压支架关键部件、系统稳定的因素。首先,鉴于液控单向阀和安全阀在支架液压系统性能的突出作用,本文建立三维流场模型,利用计算流体力学软件FLUENT对液控单向阀和安全阀进行数值模拟,研究其内部流动对性能的影响。结果表明液控单向阀在不同阀芯开度,不同流量时的压力损失有较大的差别,阀芯开度增大到一定程度时,在节流口附近引起的压力损失随阀芯开度增大而变化很小,总压力损失的减小量随阀芯开度增大也逐渐减小,液体在阀座拐角处、阀套通油孔、阀套与阀壳形成的容腔等处产生漩涡。对于安全阀而言,阀芯没有全开时,在节流口出口附近出现低压区;阀芯全开时(1mm),在溢流口入口附近出现低压区,且范围增大;安全阀入口压力不变时,最大流速出现在溢流口处且随阀芯开度增大而增大,阀芯溢流口总是存在漩涡,漩涡范围随阀芯开度增大而减小。其次,建立各系统数学模型,通过动态特性理论分析及使用功率键合图法结合数字仿真软件Matlab/Simulink分别对于液压支架关键部件、液压系统进行了动态特性分析。分析结果表明:合适的阀芯承压面面积A,降低阀口流量增益Kq,增加系统总液容C+C1,提高有效阻尼比可以增加液控单向阀系统稳定性;安全阀阀芯与阀套搭合量、弹簧刚度、阀芯部分的质量、溢流口面积等参数对安全阀动态特性有较大的影响。顶板突然来压时,顶板下沉速度为0.1m/s时,阀腔压力曲线和溢流量曲线没有波动。系统动态性能良好,当下降速度增加到0.12m/s时,系统压力在35MPa附近振荡,系统动态性能开始恶化,最大瞬时溢流量达到326.6L/min,溢流流量呈现振荡现象,不断有大流量阶跃。再次,在液压支架关键部件流动规律数值模拟及整体系统动态特性仿真的基础上,对支架实物的关键部件和支架系统进行了基于2500吨压架实验台的实验研究。分别模拟现场工作条件下的工作环境和条件,对液控单向阀、安全阀的各种性能进行研究,对液压支架在工作过程中的受力情况进行了分析。结果表明:在额定工况下的支架关键部件强度、寿命等工作性能良好,泄露性能较差;液压支架系统中,支架顶端受力的位置对于支架各部位的应力有显著的影响,但在外主筋后圆弧、顶梁外主筋贴板旁处于刚度转换处,应力一直较大,易出现塑性变形。最后,针对在支架应用过程出现的压架事故进行了分析,认为基岩下沉量大于支架初撑压力是事故的主要原因。利用理论计算及ABAQUS软件渗流-应力耦合模型进行模拟分析了顶板压力受到岩层及渗流流体的耦合作用下的活柱下缩量,精确的计算了复合破断块整体下沉量,发现支架工作阻力与活柱下缩量近似呈双曲线关系,支架工作阻力为10000kN时防水煤岩柱下沉量与支架活柱下缩量急剧减小。本文通过数值分析及仿真模拟揭示了液压支架关键部件和支架系统的内部流动规律、动态特性,在试验中找出了支架的薄弱部位,并针对典型的支架事故通过理论计算和数值模拟给出了基岩下沉和支撑压力的关系和具体的防治措施。本文的研究对于液压支架的设计、使用维护、故障诊断和事故处理具有重要的指导意义。该论文有图122幅,表6个,参考文献102篇。更多还原

【Abstract】 As the main security support equipment in the coal face, hydraulic supports have decisive significance on constructing the intrinsically safe mine.The structure, performance and the quality of the overall dynamic performance of the key components will affect the reliability and security of the whole coal face. Due to a lack of appropriate theoretical support and the experiments, the study of the hydraulic support for key components (check valve and safety valve), the flow field within hydraulic support system, flow rule and the dynamic properties of their respective is inadequate.This paper have taken the theoretical analysis, calculation, FLUENT and ABAQUS simulation, Matlab/Simulink simulation and experimental study aiming at the common ZY4000/09/21 hydraulic support. And it has analyzed the factors which will affect the key components of hydraulic support and system stability in all domains.Firstly, since the outstanding performance of the relief valve and check valve in the hydraulic support system, the paper establishes the role of three-dimensional flow model, using FLUENT, the computational fluid dynamics software, to simulate the relief valve and check valve aiming at studying the internal-flow-impact on the performance.Secondly, key components of hydraulic supports and hydraulic system dynamics have been analyzed dynamically by constructing mathematical model of the system, through theoretical analysis and using dynamic bond graph method combined with digital simulation software Matlab / Simulink respectively.Again, the material key components of the support and the support systems have been studied based on flow role of the key components in the hydraulic support simulation and the overall system dynamic performance simulation. It has studied the various properties of hydraulic of check valve, safety valve and analyzed the force condition of the support in the work process by means of simulating work environment and conditions in the site operating conditions.Finally, the paper holds that: bedrock subsidence is greater than the pressure, which is the main reason for the accident by analyzing the crushing accident in the applied process. It analysis the descending amount of piston when the roof pressure receives the coupled affect of the roof strata and the flow of seepage fluid by using the theoretical calculation and flow-mechanical model with software ABAQUS simulation.This paper revealed the flow role of key components of hydraulic support and internal system and the dynamic characteristics using numerical analysis and simulation. It has identified the weak parts in the support, and has offered the relationship between bedrock sinking and pressure support and specific prevention measures aiming at the typical crushing accident through theoretical calculation and numerical simulation. This paper has an important guiding significance on the design of hydraulic support, maintenance, troubleshooting and incident handling of.更多还原