射流速度及套管应力的ALE三维仿真分析  

ALE 3D Simulation Analysis of Jet Velocity and Casing Strength

作　　者：李明飞[1] 窦益华[1] 曹银萍[1] 于洋[1] LI Mingfei;DOU Yihua;CAO Yinping;YU Yang(School of Mechanical Engineering, Xi’an Shiyou University, Xi’an 710065, Shaanxi, China)

机构地区：[1]西安石油大学机械工程学院

出　　处：《力学季刊》2019年第2期362-372,共11页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(51374171)

摘　　要：聚能射孔是包括炸药爆轰、药型罩压垮形成射流、射流侵彻射孔枪和套管的复杂动态过程,包含能量、质量、速度、变形之间的转化和平衡.本文应用LS-DYNA软件,建立射孔弹-射孔枪-套管三维模型,应用ALE算子分离算法,每一迭代步分为两阶段,先执行网格随物质运动的拉格朗日算法,再执行穿过单元边界的质量、内能和动量的欧拉映射算法,实现爆轰过程、药型罩固流转化、射流高速侵彻套管的大变形和流固耦合仿真,分析爆轰波叠加对能量、密度、射流速度和套管强度影响.一枚射孔弹射孔时,总能量转化为金属射流能量的转换率为13.1%,三枚时为23.1%,爆轰波叠加引起射流转化能量增强.三枚的射流总能量达到133 kJ,超过三个单枚之和75 kJ的77.3%,说明爆轰波重叠使得爆轰产物对射流能量有持续补充作用,对提高孔深有利.射孔弹增加,射流平均能量增大,爆轰产物平均能量减小,但射流和爆轰产物总能量增大,说明弹间的相互作用强烈,爆轰更彻底,对提高孔深有利.三枚较一枚射孔弹射穿套管的时间提前了8μs,最大应力增加了260 MPa,三枚射孔弹时,套管应力值超过材料屈服强度范围较单枚增加了2.5 mm的圆环,爆轰重叠区域中心的套管应力为965 MPa,较单枚时的226 MPa提高了739 MPa,说明爆轰波弹间叠加加重了对套管的伤害.本文实现了射流形成机理、能量和速度转化和射流侵彻过程的流固耦合动态力学分析,搞清了爆轰波叠加对能量、密度、射流速度和套管强度的影响规律.Perforation is a complex dynamic process, including explosive detonation, cone collapse forming jet, jet penetrating the hollow steel carrier and casing, which involving the transformation and balance between energy, mass, velocity and deformation.LS-DYNA software was applied in this article. The 3D model of cone charge-hollow steel carrier-casing was established.Detonation process, solid-liquid transformation of cone, and the liquid-solid coupling of large deformation during high-speed jet penetrating casing could be achieved by the separation algorithm of the ALE operator. During calculation, each iteration step was divided into two stages. The first stage was with the Lagrange algorithm in which the grid moved with material. The second stage was the Euler mapping algorithm in which the quality, internal energy, and momentum passing through the unit boundaries were calculated. Based on the above methods, effect of the detonation wave superposition on energy, density, jet velocity and casing strength were studied. It was found that the conversion rate of total energy into jet energy was 13.1 % with one cone charge, while23.1 % when three pieces of cone charges were applied. The jet energy was enhanced by detonation wave superposing. The total energy of three jets(133 kJ) reached more than 77.3 % times of the sum of three single ones(75 kJ). It indicates that the overlap of detonation waves makes a continuous supplementary of jet energy, which is beneficial to the improvement of hole depth. With the increase of cone charge numbers, the average jet energy increases, the average energy of detonation product reduces, and the total energy of jet and the detonation products increase. It shows that the interaction among cone charges is strong and the detonation is thorough. While considering the time it takes to perforate the casing, it is 8 μs faster for three cone charges than it for a single one.When three cone charges were applied, the maximum stress increases 260 MPa, the difference between the casing stress valu

关 键 词：套管动力强度 动态力学分析 射流速度 ALE法 爆轰波叠加 

分 类 号：TE932[石油与天然气工程—石油机械设备]