{"title":"External Flow Field and Rock Erosion Characteristics of a Coaxial Straight-Swirling Mixed Jet","authors":"Peng Du, Zhao Peng","doi":"10.1002/ese3.2072","DOIUrl":null,"url":null,"abstract":"<p>Radial jet drilling is an effective technology for mining coal-bed methane. A self-propelled jet bit greatly affects drilling efficiency. Simulations and laboratory experiments using a coaxial straight-swirling mixed jet (CSMJ) were performed to study the flow field and rock erosion characteristics, and analyze laws influencing key structural parameters (straight-swirling flow ratio <i>N</i>, slot length–width ratio <i>d</i><sub>r</sub>/<i>d</i><sub>s</sub>, mixing chamber length–diameter ratio <i>L</i><sub>q</sub>/<i>D</i><sub>q</sub>, and linear segment length–diameter ratio <i>L</i><sub>f</sub>/<i>d</i><sub>f</sub>) on the flow field and rock erosion characteristics, and study the change law of the axial velocity of the flow field under different structural parameters and the distribution law of the three-dimensional velocity along the radial direction at the non-dimensional injection distance of 5.56. The CSMJ displayed characteristics of a straight jet, having a high-velocity area near the axis. The velocity was attenuated with increasing dimensionless jet distance <i>L</i><sub>s</sub>/<i>d</i><sub>f</sub>. The bit also displayed characteristics of a swirling jet, with an obvious jet diffusion with increased <i>L</i><sub>s</sub>/<i>d</i><sub>f</sub>. <i>N</i> affected the distribution ratio of the straight and swirling jets, and <i>d</i><sub>r</sub><i>/d</i><sub>s</sub> mainly affected CSMJ rotational shear energy. With the centerline velocity and radial distribution of the CSMJ as evaluation indices, the optimal parameters of the CSMJ suitable for self-propelled drilling were <i>N</i> = 0.46, <i>d</i><sub>r</sub>/<i>d</i><sub>s</sub> = 3.88, <i>L</i><sub>q</sub>/<i>D</i><sub>q</sub> = 0.67, and <i>L</i><sub>f</sub>/<i>d</i><sub>f</sub> = 0.56. Optimal flow field parameters also optimized the erosion capability, realizing the mutual verification of experimental and simulation results. The erosion hole crushing volume was used as the evaluation sequence. The parameter's sensitivity to the rock erosion volume was <i>L</i><sub>s</sub>/<i>d</i><sub>f</sub> > <i>L</i><sub>q</sub>/<i>D</i><sub>q</sub> <i>> d</i><sub>r</sub>/<i>d</i><sub>s</sub> > <i>N</i>. The results provide engineering guidance for determining reasonable parameters for radial jet drilling.</p>","PeriodicalId":11673,"journal":{"name":"Energy Science & Engineering","volume":"13 3","pages":"1402-1413"},"PeriodicalIF":3.5000,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ese3.2072","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Energy Science & Engineering","FirstCategoryId":"5","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/ese3.2072","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
Radial jet drilling is an effective technology for mining coal-bed methane. A self-propelled jet bit greatly affects drilling efficiency. Simulations and laboratory experiments using a coaxial straight-swirling mixed jet (CSMJ) were performed to study the flow field and rock erosion characteristics, and analyze laws influencing key structural parameters (straight-swirling flow ratio N, slot length–width ratio dr/ds, mixing chamber length–diameter ratio Lq/Dq, and linear segment length–diameter ratio Lf/df) on the flow field and rock erosion characteristics, and study the change law of the axial velocity of the flow field under different structural parameters and the distribution law of the three-dimensional velocity along the radial direction at the non-dimensional injection distance of 5.56. The CSMJ displayed characteristics of a straight jet, having a high-velocity area near the axis. The velocity was attenuated with increasing dimensionless jet distance Ls/df. The bit also displayed characteristics of a swirling jet, with an obvious jet diffusion with increased Ls/df. N affected the distribution ratio of the straight and swirling jets, and dr/ds mainly affected CSMJ rotational shear energy. With the centerline velocity and radial distribution of the CSMJ as evaluation indices, the optimal parameters of the CSMJ suitable for self-propelled drilling were N = 0.46, dr/ds = 3.88, Lq/Dq = 0.67, and Lf/df = 0.56. Optimal flow field parameters also optimized the erosion capability, realizing the mutual verification of experimental and simulation results. The erosion hole crushing volume was used as the evaluation sequence. The parameter's sensitivity to the rock erosion volume was Ls/df > Lq/Dq> dr/ds > N. The results provide engineering guidance for determining reasonable parameters for radial jet drilling.
期刊介绍：
Energy Science & Engineering is a peer reviewed, open access journal dedicated to fundamental and applied research on energy and supply and use. Published as a co-operative venture of Wiley and SCI (Society of Chemical Industry), the journal offers authors a fast route to publication and the ability to share their research with the widest possible audience of scientists, professionals and other interested people across the globe. Securing an affordable and low carbon energy supply is a critical challenge of the 21st century and the solutions will require collaboration between scientists and engineers worldwide. This new journal aims to facilitate collaboration and spark innovation in energy research and development. Due to the importance of this topic to society and economic development the journal will give priority to quality research papers that are accessible to a broad readership and discuss sustainable, state-of-the art approaches to shaping the future of energy. This multidisciplinary journal will appeal to all researchers and professionals working in any area of energy in academia, industry or government, including scientists, engineers, consultants, policy-makers, government officials, economists and corporate organisations.
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