摘要
空化射流的冲蚀效果与冲蚀模式研究对于提高射流的导向压裂能力至关重要,导流口结构和靶面对出口射流施加壁面约束作用,影响射流的冲蚀效果,但其影响规律及冲蚀模式演变过程尚不清晰。在喷嘴下方增设导流口结构,分析导流口壁面和靶物壁面对射流空化发展过程的影响机制;基于冲蚀试验,获取试样的质量损失及表面冲蚀形貌,分析导流口直径、长度及靶距对射流冲蚀效果的影响规律及其冲蚀模式的演变规律,进而探究不同冲蚀模式下射流对砂岩的冲蚀效果。试验结果表明,增设导流口结构能够极大增强射流的冲蚀效果,与无导流口结构相比,增设导流口结构质量损失增幅达215%;随靶距增大,试样质量损失呈现双冲蚀峰,第2峰值靶距范围内(s/d=8~10)射流冲蚀效果最强;第2峰值靶距后,射流冲蚀效果衰减,减小导流口直径(D_(c)/d=4)或增大导流口长度(L_(c)/d=8),射流冲蚀效果增幅明显,试验条件下质量损失增幅可达10倍;空化射流具有不同的冲蚀模式,随靶距增大,由双环冲蚀模式变为单环冲蚀模式,且单环冲蚀模式下试样冲蚀形貌受导流口结构影响较大。开展砂岩冲蚀试验,第1峰值靶距下,冲蚀坑呈倒漏斗型,底部表面均匀;第2峰值靶距下,冲蚀坑深度及体积大幅提高,底部有明显突起。研究成果揭示了导流口结构和靶距形成的壁面约束作用对射流冲蚀效果及冲蚀模式的影响规律,为提高水射流射孔导向压裂效果提供了技术支撑。
The research on the erosion effect and erosion pattern of the cavitating jet is essential to improve the jet’s guided fracturing ability.The guide port structure and the target surface impose wall constraints on the jet outlet flow and affect the jet erosion effect,but its influence law and the evolution process of erosion pattern are still not clear.The influence mechanism of the radial wall constraint formed by the diameter and length of the guide port and the flow wall constraint formed by the impinging distance on the development and collapse of jet cavitation is analyzed.Based on the erosion test,the mass loss and surface erosion morphology of the sample are obtained.The influence law of the structural size of the guide port,the impinging distance on the jet erosion effect and the evolution law of the erosion pattern are analyzed,so as to explore the erosion effect of the jet on the sandstone under different erosion patterns.The experimental results show that the added guide port structure can greatly enhance the jet erosion effect.Compared with the normal organ⁃pipe nozzle,the guide port⁃nozzle has a mass loss increase of 215%.With the increase of the impinging distance,the sample mass loss presents a characteristics of two erosion peaks,and the jet erosion achieves the strongest in the range of the second peak impinging distance(s/d=8-10).After the second peak impin⁃ging distance,the jet erosion effect decreases sharply.By reducing the guide port diameter(D_(c)/d=4)or increasing the guide port length(L_(c)/d=8),the erosion effect increases significantly,the mass loss increases by 10 times.The cavitating jet can produce different erosion patterns,with the increase of impinging distance,the double⁃ring erosion pattern changes to single⁃ring erosion pattern,and the erosion morphology of the sample under single ring erosion pattern is greatly affected by the guide port structure.A sandstone erosion test was carried out.It was found that under the first peak impinging distance,the erosion pit appears as inverted funnel⁃shaped and the bottom surface is uniform.Under the second peak impinging distance,the depth and volume of the erosion pit are greatly im⁃proved,and there are obvious protrusions at the bottom.The research results reveal the influence law of the wall con⁃straint formed by the guide port structure and impinging distance on the jet erosion effect and erosion pattern,which provide a technical support for improving the guided fracturing effect of water jet technology.
作者
潘岩
马飞
蔡腾飞
孟凌霄
祝启恒
孙智祥
PAN Yan;MA Fei;CAI Tengfei;MENG Lingxiao;ZHU Qiheng;SUN Zhixiang(School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China;Shunde Graduate School,University of Science and Technology Beijing,Foshan 528399,China;Lingyuan Iron&Steel Group Co.,Ltd.,Chaoyang 122500,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2023年第S02期618-625,共8页
Journal of China Coal Society
基金
国家重点研发计划重点专项资助项目(2021YFB3401502)
中央高校基本科研业务费资助项目(FRF-TP-22-027A1)。
关键词
空化射流
壁面约束作用
导流口结构
冲蚀模式
冲蚀效果
cavitating jet
wall constraint effect
guide port structure
erosion pattern
erosion effect
