磨料水射流钻头破岩过程的力学分析

研究发现钻孔孔底凸台是限制钻头钻进速度的关键因素,为了消除凸台,提高钻进速度,提出利用磨料水射流钻头破碎硬岩.对原三翼钻头和磨料水射流钻头破岩过程进行了受力分析得出原三翼钻头硬岩钻进时破岩方式为磨削,磨料水射流钻头破岩方式为切削.实验室硬岩钻进实验表明:缩小前导钻头刀片间距的改良型钻头钻进速度是原三翼钻头的1.57倍,扭矩比原三翼钻头增大了11.3%,且磨损加剧;磨料水射流钻头钻进速度是原三翼钻头的3.72倍,扭矩比原三翼钻头减小34.0%,未见明显磨损.理论分析和实验结果表明,磨料水射流钻头从根本上解决了硬岩钻进时速度慢,刀具磨损大的问题.     

磨料水射流钻头喷嘴设计与试验研究

提出利用磨料水射流钻头解决在硬岩中钻孔速度慢的问题.通过磨料水射流钻头工作原理分析得出喷嘴结构制约了冲孔速度,是决定钻头破岩效率的关键因素.运用均匀设计法和Fluent数值模拟对影响冲孔速度的主要参数进行了研究,确定了磨料水射流钻头喷嘴的最优结构参数和实验参数,得出了喷嘴结构参数与泵压和磨料浓度之间存在交互作用.实验室岩石钻进实验表明,优化后的磨料水射流钻头硬岩钻进速度是原三翼钻头的5.6倍,是对照组1的1.25倍,是对照组2的1.18倍,表明在硬岩中钻进具有显著优越性.     

超高压水射流破岩过程中的应力波效应分析

选取200,220和260MPa射流压力和3种岩样,实验研究非淹没条件下破岩效果的宏观规律.针对岩石在超高压水射流作用下的破碎特性,建立球面应力波在岩石介质中传播的波动方程.运用拉格朗日方法描述岩石质点的位移场和速度场.利用Matlab对波动方程进行计算求解,分析超高压水射流冲击下岩石破裂时序演化过程,建立岩石宏观断裂规律与微观破坏机制间的联系.研究表明:超高压水射流作用下岩石的破坏主要表现为拉伸破坏;岩石受力在应力波效应下呈现两种状态,即先拉伸后压缩应力状态与压缩应力状态;理论计算分析与实验结果基本吻合,表明利用该方法分析超高压水射流破岩机理是可行的.     

增压式脉冲水射流多脉冲特性试验研究

射流尖端产生的水锤效应有助于硬岩的高效破碎.为进一步明确增压式脉冲水射流初始脉冲(射流尖端)特性,基于超高速成像系统,开展增压式脉冲水射流流场信息采集试验,并以晕轮为标记点,对射流多脉冲尖端的瞬时速度和穿透距离进行定量表征.结果表明：增压式脉冲水射流在单周期传播过程中孕育多重脉冲特征,多脉冲通过追逐-逼近及覆盖动态竞争成为初始脉冲,初始脉冲最大速度发生于第2脉冲之中.同时,多脉冲动态竞争导致射流存在“双峰”水锤优靶点,随着预定冲蚀靶距的增加,初始脉冲峰值速度发生位置由第1脉冲迁移至第2脉冲,这即意味着水锤优靶点由近喷嘴第1靶点迁移至远喷嘴第2靶点.研究结果为进一步利用增压式脉冲水射流初始脉冲提供依据和参考.     

高压空化水射流破岩主要影响因素的研究

为了探讨高压空化水射流的空蚀能力与水力参数、岩石性质的相互关系及各参数影响破岩效果的内在机理,通过在不同泵压和围压条件下,针对不同孔隙率的岩石对高压空化水射流破碎岩石效果进行了一系列实验研究.结果表明:空蚀效果(空蚀质量、空蚀深度)随泵压增加成二次函数关系增加,随围压增加成二次函数关系减少;空泡云长度随泵压的增加而增大.随围压的增大而减小,并能较好的拟合成三次曲线函数关系,空泡云长度直接决定有效靶距,从而影响空蚀效果;本实验条件下,泵压在7 MPa时发生空化现象,并能破碎单轴抗压强度为96MPa的砂岩;岩石的孔隙率对空化水射流的破岩能力影响较大,孔隙率越高的岩石越容易被空化水射流破碎.     

高压水射流与机械联合作用处理堵塞油管

在油田开发过程水泥浆堵塞油管现象时有发生.传统的处理方法是将这些堵塞的油管报废,结果造成很大的浪费.在系统研究高压水射流流动规律和动力特性基础上,深入分析了水力与机械联合破岩机理,根据不同使用条件和适用对象,对水射流参数进行了调整,对钻头切削齿和喷嘴布置进行合理的设计.首创了一种高压水射流处理水泥堵塞油管新技术,设计制造了清洗堵塞油管专用设备和工具,现场实验取得了突破性进展.     

基于Fluent自振脉冲射流腔体结构参数的数值优化

自激振荡脉冲射流可以有效提高深部煤岩破蚀效率.为设计破蚀煤岩效率较高的自激振荡脉冲射流发生装置,基于流体力学基本原理,利用Fluent软件对自激振荡脉冲射流进行数值模拟,分析不同的腔体结构对脉冲射流峰值速度的影响.采用大涡模型(LES)进行计算,通过数值模拟发现,自激振荡脉冲射流速度云图和压力云图符合涡旋碰撞理论和脉冲射流发生原理.在特定的参数(腔长L=4.5mm,腔径D=8mm,下碰撞壁收敛角α=120°,上下喷嘴直径分别为d_1=1mm,d_2=1.1mm)下,自激振荡脉冲射流峰值速度最大,为231.21m/s,相比于入口速度提高了92.68%,脉冲射流冲蚀效果较好.     

新型滚珠旋转导致脉冲发生的试验研究

为了解决水力破岩、有效切割金属等工程问题,高压水力脉冲不失为一种有效方法,依据日常生活中的口哨原理提出了一种新型滚珠旋转脉冲喷嘴。新型滚珠旋转脉冲喷嘴产生脉冲机理极其复杂,为验证其脉冲效果,采用流速为50 m/s的高压泵对该喷嘴进行了初步的试验研究,并与普通喷嘴产生的高压水射流进行比较。试验研究结果表明,新型滚珠旋转脉冲喷嘴能产生高频脉冲;普通喷嘴产生的射流属普通湍流,无明显脉冲现象;新型滚珠旋转脉冲喷嘴产生的脉动压力远高于普通喷嘴产生的高压射流,有利于破碎岩石或金属。试验研究可为工程设计提供参考。     

电液压脉冲水射流强化金属表面的研究

分析电液压脉冲水射流的工作原理及电液压脉冲水射流发生器的设计方案,对射流发生器的聚能效应和射流的运动进行探讨.实验表明采用电液压脉冲水射流冲击金属表面,的确能使金属表面的强度和硬度得到提高.     

脆性岩石粒子冲击理论模型与实验

为了更好的得到粒子冲击脆性岩石的规律,在粒子冲击脆性岩石物理模型的基础上,根据能量守恒原理、牛顿定律和梅尔定律等,建立了粒子冲击作用下脆性岩石破碎体积的理论模型.模型计算的结果和室内实验的结果基本吻合,模型计算和室内实验的结果表明,粒子的冲击速度、直径是影响岩石破碎体积的关键因素.粒子的速度和粒子射流压力近似呈线性函数关系.随着粒子速度的增加,粒子的破岩体积逐渐的增大.粒子速度和破岩体积之间近似的呈幂函数关系,幂指数为1.6.     

脉冲水气射流的破岩实验研究

利用脉冲水气射流喷嘴在振荡腔内引入空气,与自激脉冲射流掺混形成脉冲水气射流;当泵压为7．5MPa时,进行了2组冲蚀实验,冲蚀抗压强度为6．9MPa的混凝土,第一组实验分析了不同腔长对脉冲水气射流和脉冲射流冲蚀效果的影响,第二组实验分析了不同开孔孔径下脉冲水气射流的冲蚀效果。实验结果表明：泵压一定时,在合适的腔长下,脉冲水气射流比脉冲射流的破岩效果好,且存在一个最佳进气方式使脉冲水气射流的破碎体积最大。     

牙轮钻头喷嘴射流破岩机理研究

本文以喷嘴射流冲蚀岩石为依据，对牙轮钻头的破岩方式、喷嘴射流的水力破岩和水力辅助破岩机理以及破岩的基本作用和影响因素进行了分析研究。结果表明，在现有机泵条件下牙轮钻头喷嘴射流对泥岩、页岩和粗粒砂岩具有直接水力破岩作用，对石灰岩、细粒砂岩有较好的水力辅助破岩作用。喷嘴射流冲击压力、射流的脉动特性、岩石的孔隙度和裂缝发育条件是影响水力破岩和水力辅助破岩的三个重要因素     

A new method of combined rock drilling

Based on the technologies of traditionally mechanical drilling and water jet, we propose a new method of abrasive water jet in combination with rock drilling, and establish a combined rock drilling system for the gas pre-drainage. This study chose the common sandstone and silicon limestone as the rock sample. A series of experiments were completed in the case of dry drilling, existing technology drilling, combined drilling with high pressure water jet and combined drilling with abrasive water jet, respectively. The drilling efficiency and performance were contrasted and analyzed in detail. The results indicate that it is better to choose the method of combined drilling with the high-pressure water jet for soft rocks. The method of combined drilling with abrasive water jet is feasible for the hard rock drilling and has higher drilling efficiency and performance. In this paper, compared with the existing technology, the drilling depth has increased by about 65%, the axial force and torque have reduced by about 14% and 17%, respectively, and the drill wear reduces obviously in the same conditions.     

Application of high-pressure water jet technology and the theory of rock burst control in roadway

This paper puts forward using high-pressure water jet technology to control rock burst in roadway, and analyzes the theory of controlling rock burst in roadway by the weak structure zone model. The weak structure zone is formed by using high-pressure water jet to cut the coal wall in a continuous and rotational way. In order to study the influence law of weak structure zone in surrounding rock, this paper numerically analyzed the influence law of weak structure zone, and the disturbance law of coal wall and floor under dynamic and static combined load. The results show that when the distance between high-pressure water jet drillings is 3 m and the diameter of drilling is 300 mm, continuous stress superposition zone can be formed. The weak structure zone can transfer and reduce the concentrated static load in surrounding rock, and then form distressed zone. The longer the high-pressure water jet drilling is, the larger the distressed zone is. The stress change and displacement change of non-distressed zone in coal wall and floor are significantly greater than that of distressed zone under dynamic and static combined load. And it shows that the distressed zone can effectively control rock burst in roadway under dynamic and static combined load. High-pressure water jet technology was applied in the haulage gate of 250203 working face in Yanbei Coal Mine, and had gained good effect. The study conclusions provide theoretical foundation and a new guidance for controlling rock burst in roadway.     

磨料射流辅助三翼钻头破岩实验研究

通过对磨料射流辅助三翼钻头破碎岩石的力学分析,理论上给出了提高钻进速度的依据,利用自行设计的磨料射流实验系统,采用收敛型喷嘴以不同泵压对预制水泥试件进行冲蚀实验,试验研究表明,在泵压及磨料浓度保持不变的情况下,随着冲蚀深度(靶距)的增加,磨料射流的破岩能力先增大后减小,呈抛物线型变化,存在破碎的最优靶距;随着试件硬度的增加,破岩速度减小,冲蚀深度减小,但破岩最优靶距没有变,同一靶距下,破岩速度变小;随着泵压的增大,磨料射流的最优靶距随之增大,最优靶距受喷嘴加速直线段长度的影响;通过致密砂岩的钻进对比实验得出,在同等扭矩及推力条件下,磨料射流辅助钻进的效率可以提高63.4%.     

Progress on the hydraulic measures for grid slotting and fracking to enhance coal seam permeability

A method of hydraulic grid slotting and hydraulic fracturing was proposed to enhance the permeability of low permeability coal seam in China. Micro-structural development and strength characteristics of coal were analysed to set up the failure criterion of coal containing water and gas, which could describe the destruction rule of coal containing gas under the hydraulic measures more accurately. Based on the theory of transient flow and fluid grid, the numerical calculation model of turbulence formed by high pressure oscillating water jet was used. With the high speed photography test, dynamic evolution and pulsation characteristics of water jet water analysed which laid a foundation for mechanism analysis of rock damage under water jet. Wave equation of oscillating water jet slotting was established and the mechanism of coal damage by the impact stress wave under oscillation jet was revealed. These provide a new method to study the mechanism of porosity and crack damage under high pressure jet.Fracture criterion by jet slotting was established and mechanism of crack development controlled by crack zone between slots was found. The fractures were induced to extend along pre-set direction,instead of being controlled by original stress field. The model of gas migration through coal seams after the hydraulic measures for grid slotting and fracking was established. The key technology and equipment for grid slotting and fracking with high-pressure oscillating jet were developed and applied to coal mines in Chongqing and Henan in China. The results show that the gas permeability of coal seam is enhanced by three orders of magnitude, efficiency of roadway excavation and mining is improved by more than 57%and the cost of gas control is reduced by 50%.     

脉动射流驱散上隅角积聚瓦斯的模拟实验研究

根据相似理论研制了实验装置 ,通过实验验证了脉动射流驱散上隅角积聚瓦斯的科学、有效性 ;进行了脉动射流不同旋转方向的实验 ,并考察了主风速、脉动射流风速和旋转频率等参数的影响 .实验表明 :当脉动射流旋转方向与主风流方向相同时驱散上隅角积聚瓦斯的效果较好 ,提高脉动射流风速和降低频率可显著地提高治理上隅角积聚瓦斯的效果 .     

石油工程岩石水力破碎特性研究

石油钻井和开采作业的对象是地层岩石,水力冲蚀破岩（压裂）又占有十分重要的位置。然而,对于不同物理力学性质的岩石与水力冲蚀破岩的内涵关系和定量指标,还没有进行系统的研究。文中针对这一问题,根据石油工程岩石特征,以岩石物理力学性质为基础,通过理论分析和大量的室内实验研究,把石油工程岩石分为４大类１１种。以岩石的抗压强度为定量指标,找出了不同岩石类型的水力冲蚀破碎的定量关系,其水力临界值压力系数在０１７２～０２６９之间,并提出了石油工程作业的水力压力值的设计计算式,实验得出了水力冲蚀岩石的滞后临界时间,为石油工程作业提供了理论依据和设计方法。     

浅水横流中底部水平热水射流近区的初始稀释--(Ⅱ)特性分析

对多种不同的流速比、不同的喷口密度佛汝德数的浅水横流中水平热水浮力射流进行了大量的数值试验，对整个流场的流动特性作了详尽的分析，得出流速比和密度佛汝德数是影响流场和温度场的主要因素。在大流速比情况下，射流存在分叉现象，流速比R=0．10为附壁（底）流动现象的临界值，并给出了最大入侵深度与流速比的拟合关系式。