共查询到20条相似文献，搜索用时 140 毫秒
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建立了稳态热传导问题的有限差分方程,编写了相应的温度场差分计算程序,借此可求得不同恒温边界条件下带内热源的矩形区域内的温度分布,然后采用计算机图形学原理编写了图形显示程序,并将所得离散的温度分布数据转化为相应的图形.最后,基于所得计算图形讨论了相应区域内的热传导特性. 相似文献
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吴晓 《常熟理工学院学报》2009,23(10):84-88
中引式气力输送系统具有独立、串联和远近距离均适应的优点．通过实验研究,探讨了中引式气力输送系统的流动模式、管道阻力特性和输送压力频谱特性等．实验结果表明,中引式气力输送随着操作气速的变化,管内灰栓的流动模式也相应发生变化,分别为：柱塞流、栓流和悬浮流;柱塞流压力频谱较小,灰栓、气栓相间的多栓流属基本稳定流动;栓流压力频谱振幅最大,易成为独栓,属不稳定流动,输送量与柱塞流相当;悬浮流压力频谱最低,属稳定流动,输送量最低,输送速度最快,管道易磨损．柱塞流、栓流及悬浮流模式,对于给定物料操作气速与输送平均压力之间随着操作气速增加,输送压力逐渐下降． 相似文献
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文章采用数值模拟的方法来模拟钢渣在流化床中的碳酸盐化反应。运用双流体模型来描述流化床中的气固两相流动。采用未反应核模型计算反应速率,扩散系数根据反应过程中颗粒孔隙结构的变化进行了相应的修正。通过UDF自定义程序导入化学反应速率,实现流化床内气固两相流动、传质和化学反应之间的耦合。模拟结果可知颗粒粒径、反应温度、吹气速度、CO_2浓度均对反应有一定的影响,缩小颗粒粒径,提高反应温度、吹气速度、CO_2浓度都可以提高反应效率,其中CO_2浓度对反应速度影响较大。 相似文献
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经过测试确定了吴起原油加注降凝剂的最优类型,给出吴起原油添加BEM—W降凝剂的最佳浓度和最佳温度,绘制了相应粘温曲线和流变曲线．依据SY／T5767-2002给出原油安全进站温度,这样,为安全、平稳、高效管道输送提供依据． 相似文献
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王小玉 《西安文理学院学报》2006,9(1):44-47
为实施管道安全风险评估,需要收集、存储和处理大量的管道信息,为此开发一套全国石油天然气管道安全管理信息系统.该系统在Microsoft Visual Basic 6.0环境下设计了一系列可视化界面并通过Access数据库解决了管道地理信息和属性信息的动态管理,在电子地图上利用MapInfo MapX 5.0控件实现了管线图形的动态管理,并通过管线内插节点解决了大跨度管线图形的正常显示及MapX节点编辑模式下系统异常的问题.该系统已被用户用于石油天然气管道信息管理,效果良好. 相似文献
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王春旺 《数理天地(高中版)》2014,(11):41-41
1．流量
流量是指单位时间内通过管道的某一横截面的液体体积或质量．一般取体积流量，单位为m^3／s．对于流体问题，通常选取微元进行研究，将喷出的水的速度分解为水平方向和竖直方向的分速度． 相似文献
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《实验室研究与探索》2019,(2)
为了研究城市非金属燃气管道发生小孔泄漏的分布规律,通过Gambit建立一个具有多个小泄漏孔的非金属燃气管道三维模型,采用流体动力学软件Fluent模拟PE管道在不同场景下发生小孔泄漏,得到泄漏孔处的压力以及流速分布情况,并结合相应试验进行验证。模拟结果表明:管内压力与泄漏孔处压力与流速成正相关;小孔泄漏范围内,孔径对管道内的整体流量及泄漏速度的影响较小;初始压力越大、孔径越大,管内压力降低的速度越快,但最终都会趋于一个稳定值。试验管道沿程压力和流速的分布、变化情况与模拟结果基本吻合,验证了模拟的有效性,为管道泄漏检测及事故预防提供了理论依据。 相似文献
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带电粒子在匀强电场和匀强磁场中运动分别要受到电场力和洛伦兹力的作用,电场力会改变粒子的速度大小,而洛伦兹力只能改变速度的方向．由于所受力及初始条件的不同,带电粒子在电磁场中形成不同的图形．这些图形具有和谐、对称、统一的美,同时图形也反映了有关带电粒子在电磁场中运动时的不同特性．研究这些图形,可以直观地得到解题思路和方法,给人以美的享受、美的启迪,能使学生体会到物理学的美．现以例题形式解析在电磁场中几种常见的图形． 相似文献
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第18题是最后一题，分值为20分，题目是：
超声波流量计是利用液体流速对超声波传播速度的影响来测量液体流速，再通过流速来确定流量的仪器．一种超声波流量计的原理示意如图1所示．在充满流动液体（管道横截面上各点流速相同）管道两侧外表面上P1和P2处（与管道轴线在同一平面内）， 相似文献
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Semi-open heat pipes were studied experimentally in this work. A new kind of semi-open heat pipe with fluid swirl backflow
was developed on the basis of the traditional semi-open heat pipe. Heat transfer characteristics during operation and start-up
of closed heat pipe traditional semi-open heat pipe and swirl flow semi-open heat pipe were investigated. The swirl orifice's
backflow effect on enhancing the working limitation was obtained. Heat exchangers or waste heat boilers made of swirl flow
semi-open heat pipes and semi-open heat pipes have been successfully used in high or variable gas temperature engineering
applications. 相似文献
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EXPERIMENTAL STUDY ON SEMI-OPEN HEAT PIPES AND ITS APPLICATIONS 总被引：4，自引：0，他引：4
ＩＮＴＲＯＤＵＣＴＩＯＮＨｅａｔｐｉｐｅｓａｒｅｗｉｄｅｌｙｕｓｅｄｉｎｗａｓｔｅｈｅａｔｒｅ ｃｏｖｅｒｙｓｙｓｔｅｍｓ.Ｔｒａｄｉｔｉｏｎａｌｇｒａｖｉｔｙｈｅａｔｐｉｐｅ(ＣＨＰ)ｉｓｃｏｍｐｏｓｅｄｏｆｉｎｓｉｄｅｗｏｒｋｉｎｇｆｌｕｉｄａｎｄｏｕｔｓｉｄｅｃｌｏｓｅｄｓｈｅｌｌｗｉｔｈｈｉｇｈｖａｃｕｕｍｓｔａｔｅｉｎ ｓｉｄｅｉｔ.Ｓｏｍｅｐｒｏｂｌｅｍｓｗｅｒｅｆｏｕｎｄｄｕｒｉｎｇｔｈｅｉｎ ｄｕｓｔｒｉａｌａｐｐｌｉｃａｔｉｏｎｓｏｆｃｌｏｓｅｄｈｅａｔｐｉｐｅｓ (Ａｕｅｔａｌ.,2 0 0… 相似文献
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A trapped air pocket can cause a partial air lock in the top of a hump pipe zone. It increases the resistance and decreases the hydraulic cross section, as well as the capacity of the water supply pipeline. A hydraulic model experiment is conducted to observe the deflection and movement of the trapped air pocket in the hump pipe zone. For various pipe flow velocities and air volumes, the head losses and the equilibrium slope angles are measured. The extra head losses are also obtained by reference to the original flow without the trapped air pocket. Accordingly, the equivalent sphere model is proposed to simplify the drag coefficients and estimate the critical slope angles. To predict the possibility and reduce the risk of a hump air lock, an empirical criterion is established using dimensional analysis and experimental fitting. Results show that the extra head losses increase with the increase of the flow velocity and air volume. Meanwhile, the central angle changes significantly with the flow velocity but only slightly with the air volume. An air lock in a hump zone can be prevented and removed by increasing the pipe flow velocity or decreasing the maximum slope of the pipe. 相似文献
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简谐激励下输流管的稳定性和混沌运动 总被引：3，自引：0，他引：3
Ｎｏｔａｔｉｏｎａｖｉｓｃｏｅｌａｓｔｉｃｃｏｅｆｆｉｃｉｅｎｔ Ａ ｃｒｏｓｓ ｓｅｃｔｉｏｎａｌａｒｅａｏｆｔｈｅｐｉｐｅｗａｌｌｄｄｉｍｅｎｓｉｏｎｌｅｓｓｆｏｒｃｉｎｇａｍｐｌｉｔｕｄｅＤｆｏｒｃｉｎｇａｍｐｌｉｔｕｄｅＥＩｆｌｅｘｕｒａｌｒｉｇｉｄｉｔｙｏｆｔｈｅｐｉｐｅｇ ａｃｃｅｌｅｒａｔｉｏｎｄｕｅｔｏｇｒａｖｉｔｙＬｌｅｎｇｔｈｏｆｐｉｐｅｍｓｐｅｃｉｆｉｃｍａｓｓｏｆｐｉｐｅＭｓｐｅｃｉｆｉｃｍａｓｓｏｆｆｌｕｉｄｎｄｉｍｅｎｓｉｏｎｌｅｓｓｆｏｒｃｉｎｇｆｒｅｑｕｅｎｃｙｔｔｉ… 相似文献
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JAIN N.C. GUPTA P. 《浙江大学学报(A卷英文版)》2006,7(3):340-346
INTRODUCTION In recent years, the subject of free convection flow has attracted the attention of a number of scholars because of its possible applications to several geophysical problems. In view of these applications, a series of investigations were made to study the flow past a vertical wall. Transpiration cooling can very effectively pro-tect certain structural elements in turbojet and rocket engines, like combustion chamber walls, exhaust nozzles or gas turbine blades from hot gases. … 相似文献
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Dong-fang Hu Zheng-liang Huang Jing-yuan Sun Jing-dai Wang Zu-wei Liao Bin-bo Jiang Jian Yang Yong-rong Yang 《浙江大学学报(A卷英文版)》2017,18(3):212-224
The effect of a gradual contraction pipe (GCP) on gas-liquid flow in a circular-sectioned horizontal to vertical 90° duct bend was investigated by computational fluid dynamics (CFD) simulation. The hydrodynamics of gas-liquid flow in 90° duct bends with and without a GCP in the vertical section were compared using a 3D steady Eulerian-Eulerian approach. The predicted static pressure in the vertical section of the pipes and the pressure drop in the whole pipe were consistent with experimental data. Results of simulations showed that liquid could distribute more uniformly at the exit of the pipe with a GCP. The increased uniformity was accompanied by an increase in pressure drop by a factor of less than 10% compared to the pipe without a GCP. The position of minimum pressure in the bend was changed by the GCP. A GCP can alter the trajectories of the fluid and secondary flow. As a result, the fluid can quickly reach a steady state downstream from the bend. 相似文献
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INTRODUCTIONThemotionoftheflowinarotatingcurvedpipeisafundamentalproblem ,whosesolutionhaspotentialapplicationsingasturbines ,elec tricgenerators ,electricmotorsandsomeequip mentsusedinseparationprocesses.Itisimpor tanttoknowtheflowstructurecharacteristic… 相似文献
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NomenclatureV-Relative velocity vectorV′-Absolute velocity vectorω-Relative vorticity vectorω′-Absolute vorticity vectorR-Pipe radiusa-Radius of cylinder for helical vortex filament2πl-Pitch of i mage helical vortex filamentQ-Flowrate in pipe with an arbitrary cross-sectionΓ-Circulation of each helical vortex filamentV0-Constant transferal velocity of vortex filaments along thez-axisΩ-Constant angular velocity of vortex filaments around thez-axis(a,χ1) ,(a,χ2) -Relative helical … 相似文献
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3D couette flow of dusty fluid with transpiration cooling 总被引：1，自引：0，他引：1
GOVINDARAJAN A RAMAMURTHY V SUNDARAMMAL K 《浙江大学学报(A卷英文版)》2007,8(2):313-322
INTRODUCTION Transpiration cooling is a very effective process to protect certain structural elements like combustion chamber walls, exhaust nozzles, or gas turbine blades in turbojet and rocket engines, from the influence of hot gases. In view of this, Eckert (1958) obtained an exact solution of the plane couette flow with transpi-ration cooling. The problem remained 2D due to the uniform injection and suction applied at the porous plates. Flow and heat transfer along a plane wall with… 相似文献