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瓦斯抽采钻孔棱状钻杆排渣原理数值模拟 被引量:11
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作者 王永龙 刘春 +2 位作者 孙玉宁 宋维宾 王振锋 《安全与环境学报》 CAS CSCD 北大核心 2015年第4期89-93,共5页
为分析棱状类钻杆应用于松软突出煤层钻进存在优势的原因,基于流体力学理论,建立了棱状钻杆排渣模型,采用有限元方法,应用标准κ-ε模型方程进行计算,对钻杆旋转与周边流体相互作用的流场特征进行分析。结果表明,在钻杆棱角处形成"... 为分析棱状类钻杆应用于松软突出煤层钻进存在优势的原因,基于流体力学理论,建立了棱状钻杆排渣模型,采用有限元方法,应用标准κ-ε模型方程进行计算,对钻杆旋转与周边流体相互作用的流场特征进行分析。结果表明,在钻杆棱角处形成"低压高速区",棱边处形成"高压低速区",钻杆棱边壁面流体产生速度、压力波动差,从而在"高压低速区"钻杆壁面形成强烈的"压差涡流"现象,减少了钻屑在孔底堆积致使钻孔堵塞的概率。应用棱状钻杆在松软突出煤层中施工钻孔,钻进深度提高34.6%,钻进效率提高21.1%,钻孔达标率由9.8%提高到48.3%,试验期间,钻杆强度可靠,未出现丢钻、断钻现象。 展开更多
关键词 安全工程 瓦斯抽采 松软突出煤层 压差涡流 煤层钻进
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Spectral Methods for Two Dimensional Incompressible Flow
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作者 郭本瑜 马和平 《Journal of Mathematical Research and Exposition》 CSCD 1999年第2期375-390,共16页
We take the two dimensional vorticity equations as models to describe spectral methods and their combinations with finite difference methods or finite element methods, which are applicable to other similar nonlinear ... We take the two dimensional vorticity equations as models to describe spectral methods and their combinations with finite difference methods or finite element methods, which are applicable to other similar nonlinear problems. Some numerical results and error estimates of these methods are given. 展开更多
关键词 vorticity equation spectral method combination method.
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Performance estimation of bi-directional turbines in wave energy plants
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作者 S.Anand V.Jayashankar +3 位作者 S.Nagata K.Toyota M.Takao T.Setoguchi 《Journal of Thermal Science》 SCIE EI CAS CSCD 2007年第4期346-352,共7页
Oscillating water column (OWC) based wave energy plants have been designed with several types of bidirectional turbines for converting pneumatic power to shaft power. Impulse turbines with linked guide vanes and fix... Oscillating water column (OWC) based wave energy plants have been designed with several types of bidirectional turbines for converting pneumatic power to shaft power. Impulse turbines with linked guide vanes and fixed guide vanes have been tested at the Indian Wave Energy plant. This was after initial experimentation with Well's turbines. In contrast to the Well's turbine which has a linear damping characteristic, impulse turbines have non-linear damping. This has an important effect in the overall energy conversion from wave to wire. Optimizing the wave energy plant requires a turbine with linear damping and good efficiency over a broad range of flow coefficient. This work describes how such a design can be made using fixed guide vane impulse turbines. The Indian Wave Energy plant is used as a case study. 展开更多
关键词 Bidirectional turbine differential pressure flow rate impulse turbine
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