【作者】 朱万胜；

【导师】 李继志； 张作龙；

【作者基本信息】 中国石油大学 ， 机械设计及理论， 2010， 博士

【摘要】 在油气田开发系统中液压阀的应用日益广泛,然而目前国内关于以钻井液泥浆作为介质的阀尤其是适用于井下小空间作业阀的研究较为缺乏,本文针对泥浆介质方向阀进行了设计和理论分析,为更深入地对该类型元件的研究工作提供实验和理论借鉴。课题综合采用理论分析、实验研究、数值计算等方法对泥浆介质方向阀的特性和机理进行研究。首先对泥浆介质阀口流量系数及流量特性进行理论和实验分析,在此基础上设计出适合钻井工程要求的方向阀,并给出设计方法,最后利用系统仿真及流体仿真对阀的结构特性参数进行数值计算和优化分析。具体内容包括:(1)基于CFD方法和气蚀理论,采用幂律流体本构方程、RNG k ?ε湍流模式和气液两相流模型,针对钻井液系统中常用的锥阀阀口附近流场进行数值计算。通过对流场内流线形状、压力的大小以及气体体积百分比的分布情况进行分析,着重研究了阀芯半锥角、阀芯前部过渡圆弧、阀座倒角等阀口的几何参数对钻井液锥阀气穴流场的影响。(2)针对泥浆介质的特殊理化性能确定阀口流量系数实验方案,设计并研制了相关实验装置,组建了实验系统,并利用该系统,以幂律流变模型的钻井液作为介质,对锥阀、球阀、板阀三种不同阀芯形式的阀口流量系数进行实验研究。通过对四种不同结构尺寸的阀座在不同开度下的流量、压力进行测量和计算,得出了各种组合下钻井液座阀阀口流量系数及其变化规律。(3)从设计难点、结构选择和参数计算等方面介绍了所设计的几种泥浆介质方向阀,建立了一套比较完善的泥浆介质方向阀设计方法,给出了主要设计参数的计算公式,并对泥浆介质阀在制造过程中的材料选择和加工工艺进行了归纳总结,得出了一些有利于工程实用价值的结论。(4)采用对严重非线性系统分析具有突出优势的功率键合图理论,并结合MATLAB/SIMULINK等计算工具,根据所设计的泥浆介质方向阀的实际结构参数,对其相应的阀控系统进行仿真,并对仿真结果进行分析对比,优选关键结构参数,从而达到改善泥浆介质方向阀性能的目的。(5)利用SOLIDWORKS建立泥浆介质方向阀的流道模型,采用FLUENT软件对阀腔流场进行流体动力学数值计算,通过对流道内压力分布、速度分布及三维流线进行研究,深入分析了阀体结构对于流场中所存在的负压区、漩涡区以及引起流线畸变的影响,并针对上述结构提出了优化和改进措施。更多还原

【Abstract】 The hydraulic valve has been widely used in today’s oil and gas field development system. But the current domestic research on valves with drilling mud as medium is inadequate, especially on valves applicable to small space in underground operations in particular. This thesis designs and analyzes directional valve taking drilling fluid as the working media on a theoretical basis, providing some experimental and theoretical reference for more in-depth study of the types of components.The project makes a study on the characteristics and mechanism of slurry directional valve by employing comprehensively experimental research, theoretical analysis, modeling and simulation. Thesis first makes an experimental and theoretical analysis about flow coefficient and flow characteristics in valve port of slurry valve. The directional valve suitable for drilling engineering requirements is designed and the designing methods are given on this basis. Finally the numerical calculation and optimizational analysis of the valves’structure parameters are made by means of system simulation and fluid simulation.Contents include:(1) Numerical simulation calculation In the region near the valve port of the cone valve commonly used in drilling fluid systems is made, based on CFD methods and gas corrosion theory, using power-law fluid constitutive equation, RNG turbulence model and two-phase flow model. The effect of angle of poppet, arc in front of poppet and chamfer of valve seat in the flow field within cone valve is investigated emphatically by analyzing the form of stream line, pressure and distribution of gas volume percentage.(2)The test program of flow coefficient is determined for the special physical and chemical properties of drilling mud media. Some related test equipments are designed and developmented and the test system is set up. Experimental investigations are made on the flow coefficient of cone valve、ball valve and plate valve taking drilling fluid used in Power-law rheological model as the working media. The data and law of flow coefficient of poppet valve for drilling fluid are obtained in various situations by measuring flow and pressure at different opening of four constructions of valve seats.(3) Several directional valves with slurry as medium are introduced from the perspective of designing difficulties, structure selection and parameter calculation. A relatively perfect set of designing methods of slurry valve is established and the main calculation formulas of parameters are given. Material selection and processing technology of slurry valve in the manufacturing process are summarized and some useful conclusions for engineering are obtained.(4) using the power bond graph theory which is outstandingly advantageous to serious nonlinear systems analysis, combined with MATLAB / SIMULINK simulation and optimization tools, according to the actual structure parameters of the designed directional valves, the corresponding valve control system is simulated and results are compared and analyzed so as to optimize the key structural parameters and to improve the slurry media directional valve performance. (5) The flow path model of slurry media directional valve is established using SOLIDWORKS. Numerical calculation of fluid dynamics of flow field in valve pocket is made using FLUENT. By analysis of pressure distribution in convection channel, velocity distribution and three-dimensional flow lines, the influencing factors resulting in the existence of negative pressure area, whirlpool areas and stream line distortion in the flow field caused by the valve structure are analyzed deeply, and the optimization and improvement measures are proposed.更多还原