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.     

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%.     

双孕镶金刚石钻头的自平衡逆向回转破岩性能

为了揭示双钻头自平衡同步逆向回转的破岩特性,采用理论计算和数值模拟等方法,对比研究了双孕镶金刚石钻头同步逆向回转和单孕镶金刚石钻头单向回转的破岩特征,得出如下结论:双钻头在孔底呈现双向小台阶双螺旋钻进,而单钻头则呈现单向小台阶螺旋钻进;由于双钻头的内、外钻头逆向回转产生了扭矩平衡作用,对孔底岩石的作用合力更小,对地层的扰动更弱。通过室内试验对比研究得出:双钻头逆向回转情况下,孔壁更光滑、稳定;双钻头对孔底岩石能产生更多的应力集中点,且磨损较单钻头更为均匀,具有更长的使用寿命;双钻头在同等钻进参数下,钻速更快,说明双钻头更容易破岩。本文研究成果可为双钻头自平衡钻进技术的研究提供理论支撑。     

煤巷顶板锚固孔钻进岩层界面能量响应特性研究

煤巷顶板锚固孔钻进是实现其锚固的关键环节,顶板岩层交界面及软弱夹层赋存特征对锚固质量影响较大.从能量守恒原理出发,对锚固孔钻进过程中的能量进行分析,通过传感器可监测锚杆机动力装置能量指标,实现煤巷顶板岩层结构实时动态探测.研究结果表明:在一定动力条件下,钻头穿过岩层交界面和软弱夹层时,能量曲线变化较为明显,响应性强.从钻头钻速和转速的角度分析轴向推力做功与旋转扭矩做功,发现钻速、转速与钻头破岩做功之间存在较好地响应关系.钻头破碎岩石95%以上的能量来自于旋转扭矩做功,而轴向推力做功相对较小,不到钻具系统输出总能量的5%,总能量的变化曲线与扭矩做功的变化曲线基本一致.     

空气冲旋钻头牙齿失效分析与新材料实验研究

针对目前空气冲旋钻头钻进中牙齿频繁断裂、脱落以及磨损严重,导致破岩效率低、使用寿命短等问题,采用纳米改型技术,在硬质合金中掺杂纳米Al2O3制备出Al2O3/WC-Co纳米/微米复合材料,对其性能、组织结构进行分析,对其耐磨性、耐冲击性进行实验研究,结果表明:加入3%的纳米Al2O3并添加适量的抑制剂和稀土元素能明显改善Al2O3/WC-Co纳米/微米复合材料的组织结构、细化晶粒,复合材料的耐磨性和耐冲击性能得到大幅提高,较硬质合金YG8提高4～8倍.为大幅度提高钻头破岩效率,延长钻头使用寿命提供了可能性.     

滚刀滑移状态下的受力与磨损仿真分析

为探究滚刀滑移状态下破岩的受力与磨损的变化规律,基于离散单元法,建立了同时考虑滚刀自转和绕刀盘公转的滚动圆周切割模型。定义了一个滑移率参数η用于描述滚刀的滑移状态,对不同滑移率工况下滚刀破岩受力和磨损进行了对比分析,并结合工程实例对数值仿真结论进行了验证,结果表明:数值仿真中垂直力FV和滚动力FR在CSM模型计算值附近波动,两者较为吻合,表明了本文模型的合理性。数值仿真结果表明,随着滑移率η的增大,垂直力FV呈轻微减小趋势,滚动力FR明显变大,从滚动破岩到滑动破岩,垂直力FV降幅为23.6%,滚动力FR增幅达83.7%,滑动破岩将导致滚刀偏磨。工程实测数据表明,刀盘上大量滚刀处于正常磨损状态时,主要表现为推力增大。大量滚刀处于偏磨状态时,主要表现为扭矩增大,其中偏磨滚刀占比19.05%和28.57%时,扭矩增幅分别为55.85%和261.51%。滚刀正常磨损和偏磨均大量存在时,表现为扭矩推力同步增大,其中偏磨滚刀占比21.43%时,扭矩增幅为80.89%。数值仿真和实测数据表现出较高的一致性。综合4次开仓换刀结果,可将刀盘扭矩增幅超过50%作为判定大量滚刀发生偏磨的重要依据。     

煤矿巷道底板锚固孔钻渣生成机理及尺寸特征分析

利用理论分析、实验室实验及数值模拟方法研究了底板锚固孔钻进过程中两翼式钻头破岩时钻渣生成机理及尺寸特征.结果表明:两翼式钻头破岩过程实际为底板锚固孔钻渣分区域生成的过程,即锚固孔周边岩石切削破碎生成小粒径钻渣以及中部区域岩柱扭转(受压)破坏生成大粒径钻渣;底板锚固孔钻进过程中岩石的单轴抗压强度越高,钻进过程中产生的大粒...     

基于有限元分析的煤矿井下新型弧角型聚晶金刚石复合片钻头优化设计

为了提高煤矿井下硬地层的钻进效率,借鉴石油钻头的设计和加工理念,提出了一种适用于煤矿井下硬岩钻进的新型弧角型PDC钻头的设计思路。采用有限元数值模拟方法,分别对直径为113mm的弧角型聚晶金刚石复合片(PDC)钻头的切削结构和水力结构进行优化设计,得出:当采用内锥角为130°、外锥圆弧半径为20mm的冠部形状,切削齿切削角度为-15°、侧转角为4°~6°,刀翼采用直刀翼的钻头切削结构时,破岩效果最佳;喷嘴喷射角为22°~30°、方位角的设计靠近切削齿的工作面时的钻头水力结构,能够满足岩屑的有效运移。基于此,试制了直径为113mm的弧角型PDC钻头,并进行现场试验,结果表明:弧角型PDC钻头的平均寿命为626m,平均钻进时效为25m/h,与工区现用普通内凹型钻头相比,寿命提高了4倍,钻进效率提高了1倍,说明本文设计的弧角型PDC钻头能够代替普通内凹钻头应用于硬地层钻进,可同时达到提高钻进效率和降低施工成本的目的。     

三牙轮钻头齿面结构对破岩效率影响的研究

本文叙述了三牙轮钻头齿面结构对破岩效率影响的研究方法,研究工作是用全尺寸钻头在地面钻头试验架上进行。作者根据试验钻头对不同岩石钻进时所测得的钻进参数、钻进指标和钻头的井底模式,结合它们的齿面结构,分析其对破岩效率的影响,找出各钻头齿面结构的优缺点。从而对现有国产钻头提出改进意见,并将所获得的认识用于新钻头的设计之中。     

水力联合机械钻头修复失效钻孔方法及参数

为了高效修复失效瓦斯抽采钻孔,提出了水力联合机械钻头修复失效钻孔的方法.通过构建水力驱动机械钻头旋转力学理论模型与转速公式,理论研究了机械钻头扭矩M、转速n与射流压力p、力臂L、喷嘴直径d的关系;开展了M,n测试试验并确定了理论模型与转速公式的修正系数i,ε;通过对比试验验证了水射流与水力联合机械钻头破煤效果的差异性.结果表明：M值与p,L值呈线性正相关,与d²呈正相关,n值与■呈正相关;i取0.40,ε值与L值呈线性正相关,与d²呈正相关;在25.00 MPa射流压力下,水力联合机械钻头破煤体积为水射流破煤体积的11.64倍,水力联合机械钻头破煤效果优于水射流破煤效果.在工程应用中水驱动力的合理分配是该方法高效修复钻孔的技术关键.     

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.     

钻头齿面堆焊用硬质合金耐磨性试验

为了选择更合适的钻头齿面强化材料,对多种粒度的球状烧结碳化钨和粒状铸造碳化钨堆焊层分别作了磨料磨损试验,以评价其抗磨性能。用 Ｎｉ 基合金作钎料,在高真空度下将硬质合金颗粒焊至２０ Ｎｉ４ Ｍｏ 表面。试验采用多种冲击能量,磨料介质为石英砂、水和少量悬浮剂,用天平称出磨损失重。结果表明：球状烧结碳化钨或不同类型和粒度混合的碳化钨堆焊层都比现行采用的粒状铸造碳化钨具有更好的抗冲击磨料磨损能力。用球状烧结碳化钨代替粒状铸造碳化钨作钢齿钻头齿面堆焊材料是提高齿面强化效果的有效途径。     

一种适合硬膜抗磨粒磨损性能试验方法的研究

提出了一种适合评估硬膜材料抗磨粒磨损性能试验的新方法 ,并研究了各种因素对硬膜抗磨粒磨损试验结果的影响。试验发现 ,硬膜的磨损量与磨损时间以及试棒转速成正比 ;当磨料粒度在一定的范围内变化时 ,磨损量与磨料的粒度成正比 ;当磨料的粒度超过某一临界尺寸后 ,磨损速度变化不大。在粒度为 1 80目时 ,磨损试验的效果最佳。在有饱和水溶液的磨料中 ,同时存在着磨料磨损和气蚀磨损两种磨损方式。     

Composite rock-breaking of high-pressure CO2 jet & polycrystalline-diamond-compact (PDC) cutter using a coupled SPH/FEM model

CO₂ drilling is a promising underbalance drilling technology with great advantages, such as lower cutting force, intense cooling and excellent lubrication. However, in the underbalance drilling, the mechanism of the coupling CO₂ jet and polycrystalline-diamond-compact (PDC) cutter are still unclear. Whereby, we established a coupled smoothed particle hydrodynamics/finite element method (SPH/FEM) model to simulate the composite rock-breaking of high-pressure CO₂ jet & PDC cutter. Combined with the experimental research results, the mechanism of composite rock-breaking is studied from the perspectives of rock stress field, cutting force and jet field. The results show that the composite rock-breaking can effectively relieve the influence of vibration and shock on PDC cutter. Meanwhile, the high-pressure CO₂ jet has a positive effect on carrying rock debris, which can effectively reduce the temperature rising and the thermal wear of the PDC cutter. In addition, the effects of CO₂ jet parameters on composite rock-breaking were studied, such as jet impact velocity, nozzle diameter, jet injection angle and impact distance. The studies show that when the impact velocity of the CO₂ jet is greater than 250 m/s, the CO₂ jet could quickly break the rock. It is found that the optimal range of nozzle diameter is 1.5–2.5 mm, the best injection angle of CO₂ jet is 60°, the optimal impact distance is 10 times the nozzle diameter. The above studies could provide theoretical supports and technical guidance for composite rock-breaking, which is useful for the CO₂ underbalance drilling and drill bit design.     

Bionic surface design of cemented carbide drill bit

The development of a high-performance cemented carbide drill bit is of great significance to the reduction of rock drilling-cost. The non-smooth features of a biological surface provide an insight into how they can obtain low friction and good wear resistance with evolving surface morphology. By analyzing the mechanism of the surface of a dung beetle for reducing soil wear and adherence, we design a cemented carbide drill bit with a bionic surface, which is expected to have superior anti-wearing and anti-sticking properties for drilling the soft coal seam. Inspired from the characteristics of the head and pronotum surface of the dung beetle, optimized non-smooth surface of the drill bit was constructed. The working performance of this innovative drill was experimentally tested. With comparative experiments under the identical drilling conditions, the wear rates, drilling times of conventional drills and bionic drills were measured. Compared with the conventional counterpart, the drill designed exhibits better performance in reducing wear and sticking drilling-breaks, therefore achieving higher levels of efficiency. The diameter of the dome and pit on the bit surface is in the range of 0.8–1.2 mm, and the bionic drill bits could get better performance with preferable drilling speeds and wear rates.     

磨料水射流微细雕刻技术的研究

根据磨料水射流加工的特点，建立了磨料水射流加工的神经网络模型。用训练好的神经网络模型来预测给定加工条件下的进给速度，并根据加工路径和机床的特性对进给速度进行修正，并编写数控代码。通过控制水射流的进给速度来间接控制其刻蚀深度，同时获得加工轨迹的圆滑过渡，从而实现磨料水射流的雕刻工艺。本文以不锈钢为原材料，以JJ-I数控水射流机床为实验平台，根据机床的特性手工编程，成功雕刻出微型摩托车图形。     

基于人工神经网络的磨料水射流切削工艺建模

磨料水射流（AWJ）切割工艺已经被遍及世界的许多车间所采用，其优点广为人知。为了进行精密加工，如精密切割、铣削、钻孔和磨削等，必须精确预测AWJ的侵蚀深度。文章基于人工神经网络（ANN）对AWJ切割工艺进行建模。模型采用三层结构，输入变量有水射流压力、水喷嘴直径、磨料粒子粒度（直径）、磨料流量和切割头进给速度。输出量为AWJ的切割深度。样本数据在JJ-Ⅰ水射流切割机床上实验获取，A3钢样板作为切割试件。采用改进的BP算法和样本数据对建立的人工神经网络进行训练。训练好的网络以一定精度建立了AWJ切割工艺中各参数之间的映射关系。所建模型可以精确预测AWJ的切深。将该模型集成到AWJ切割机床的计算机数控器中，可以实现AWJ精密加工。     

Enhancing diamond drilling performance by the addition of non-ionic polymer to the flushing media

Drilling is a most important and crucial operation in the excavation industries.With the objective of looking into the enhancement of diamond drilling performance detailed laboratory investigations were carried out on phosphate rock.The effect of Poly (Ethylene Oxide) (PEO) added to the drilling water was studied by varying machine parameters and PEO concentration.The responses were rate of penetration and torque at the bit rock interface.Slake durability tests were also performed to understand the slaking behavior of phosphate rock in PEO solutions.     

Optimization of AWJM Process Parameters on 3D-Printed Onyx-Glass Fiber Hybrid Composite

Compared with conventional manufacturing methods, the additive manufacturing technique enhances mechanical properties. The present investigation of additive manufacturing technique is focused on delamination studies of Onyx-Glass Fiber Hybrid Polymer Composite(OGFHPC) along with surface roughness properties during machining(drilling) of composites through abrasive water jet machining(AWJM). However, delamination is a major issue during machining of OGFHPC. In order to overcome these drawbacks, t...