凿岩系统溢流阀的升力流量和失稳特性研究

发布时间：2018-06-18 05:14

本文选题：凿岩 + 溢流阀　；参考：《北京科技大学》2017年博士论文

【摘要】：凿岩钻车是矿山用于钻凿炮孔的一种设备,但由于凿岩系统中的溢流阀普遍存在着调压偏差大,压力振摆,动作不灵敏,压力损失大,噪声大等问题,在定压溢流和超压保护过程中的振荡失稳行为致使钻臂抖动,定位精确度不高,排渣困难,影响凿岩作业的效率。溢流阀是通过阀口的溢流作用,使被控制系统或回路的压力维持恒定,实现调压、稳压和限压的目的。如何使凿岩系统回路减振降噪,并有效保障凿岩钻车的持续工作能力,得到了越来越多的国内外学者的关注。本论文以凿岩溢流阀为研究对象,围绕其失稳特性进行相关研究。针对可压缩流工作介质,提出了将溢流阀等同于理想收缩喷管的方法。将溢流阀的流动状态分为三种,即亚临界、临界和超临界。根据流量比和背压比的关系曲线,将亚临界和临界流动状态用近似四分之一椭圆的轨迹来描述,并得到溢流阀的椭圆方程流量特性曲线。针对不可压缩流工作介质,基于非光滑分岔理论和延拓法,分析了锥阀溢流阀的失稳现象。为了提高其稳定特性,分析了系统回路中锥阀溢流阀的结构特点,考虑管道的弹性和阀芯碰撞阀座时的能量损失,建立了溢流阀的无量纲动力学数学模型,进行线性稳定性和Lyapunov指数分析。利用软件XPPAUT和MATLAB得到不同开启压力的相位和向量场分布图,和不同初值条件下阀芯在时域上的运动轨迹。画出单参数和双参数分岔图,理论分析Hopf分岔、极限环鞍结点分岔、广义Hopf分岔和尖点分岔等分岔现象,分析了典型的阀芯在时域上的开启高度和频谱图。对可压缩流和不可压缩流工作介质,分析了反冲盘式阀芯溢流阀的动作原理。建立了溢流阀的升力数学模型,分析了阀芯结构对升力特性的影响。介绍了衡量溢流阀流量特性的技术参数,分析了阀芯开启高度对流量特性的影响。进行了溢流阀的升力特性实验,得到了实测升力和阀进出口压差在不同开启高度和流量下的特性曲线。对理论和实测升力进行了对比分析,得到了局部阻力系数和阀芯等效面积在不同开启高度和流量下的变化规律。分析了静态失稳和动态失稳的表现形式,进行了溢流阀的失稳特性实验,利用变频器的可编程多段速功能实现泵流量的多段输出,研究流量、开启压力和入口管长度对失稳特性的影响因素。分析了频跳失稳时的水锤现象,对理论和实测水锤增压进行了对比分析。通过本文的理论分析、仿真模拟和实验验证,为凿岩系统溢流阀稳定性的设计和研究提供了一定的理论指导和依据。
[Abstract]:Rock drilling rig is a kind of equipment used to drill hole in mine, but the relief valve in rock drilling system has many problems such as large pressure adjustment deviation, pressure oscillation, insensitive action, large pressure loss, large noise and so on. The oscillatory instability in the process of constant pressure overflow and overpressure protection results in the jitter of the drill arm, low positioning accuracy and difficult slag discharge, which affects the efficiency of rock drilling. The relief valve is used to keep the pressure of the controlled system or loop constant through the relief action of the valve opening, and to achieve the purpose of regulating, stabilizing and limiting the pressure. More and more scholars at home and abroad pay attention to how to reduce vibration and noise of drilling system loop and effectively guarantee the continuous working ability of drilling rig. In this paper, the rock drilling relief valve as a research object, around its instability characteristics. A method of equating relief valve with ideal shrink nozzle is proposed for compressible flow medium. The flow state of relief valve is divided into three types: subcritical, critical and supercritical. According to the relation curve between flow ratio and back pressure ratio, the subcritical and critical flow states are described by approximately 1/4 elliptic trajectories, and the flow characteristic curves of the elliptic equation of relief valve are obtained. Based on the theory of non-smooth bifurcation and continuation method, the instability of cone relief valve is analyzed for incompressible flow medium. In order to improve its stability, the structural characteristics of the cone valve relief valve in the system loop are analyzed. Considering the elasticity of the pipeline and the energy loss when the valve core collides with the valve seat, the dimensionless dynamic mathematical model of the relief valve is established. Linear stability and Lyapunov exponents are analyzed. Using the software XPPAUT and MATLAB to obtain the phase and vector field distribution of different opening pressures and the movement track of the spool in time domain under different initial values. The single parameter and two parameter bifurcation diagrams are drawn, and Hopf bifurcation, saddle node bifurcation of limit cycle, generalized Hopf bifurcation and cusp bifurcation are analyzed theoretically. The opening height and spectrum diagram of typical spool in time domain are analyzed. The operation principle of recoil disc valve core relief valve is analyzed for compressible and incompressible flow media. The lift mathematical model of relief valve is established, and the influence of valve core structure on lift characteristics is analyzed. This paper introduces the technical parameters to measure the flow characteristics of relief valve, and analyzes the influence of the valve core opening height on the flow characteristics. The lift characteristics of the relief valve were tested and the characteristic curves of the lift force and the pressure difference between the inlet and outlet of the valve at different opening heights and flow rates were obtained. The variation of local resistance coefficient and the equivalent area of the valve core under different opening height and flow rate are obtained by comparing the theoretical and measured lift forces. The static instability and dynamic instability are analyzed, and the experiment of the instability characteristics of relief valve is carried out. The multi-stage output of pump flow is realized by using the programmable multi-stage speed function of frequency converter, and the flow rate is studied. The influence factors of the opening pressure and the length of the inlet tube on the instability characteristics. The phenomenon of water hammer during frequency hopping instability is analyzed, and the theoretical and measured water hammer pressurization is compared and analyzed. Through the theoretical analysis, simulation and experimental verification, this paper provides a certain theoretical guidance and basis for the design and study of the stability of the relief valve in rock drilling system.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD421.2

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