共查询到19条相似文献,搜索用时 78 毫秒
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涡旋运动产生的剪切力和离心惯性力是絮凝颗粒产生接触碰撞的主要作用力,而涡旋剪切力是絮凝反应的主导动力。根据这一原理,结合自激振荡脉冲射流产生机理,在管道式絮凝器中设计自激振荡腔室完成絮凝剂和原水的混合搅拌工作,并利用自激振荡原理产生有利于微絮体生成的水力条件,使絮凝效率得到提高。 相似文献
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自激振荡脉冲磨科水射流的研究 总被引:1,自引:0,他引:1
对自激振荡脉冲磨料水射流进行了大量的理论和实验研究,并与前混合磨料水射流进行了对比实验。结果表明,自激振荡脉冲磨料水射流具有很好的发展和应用前景。 相似文献
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自激振荡磨料射流原理及切割实验研究 总被引:5,自引:0,他引:5
综合前混合式磨料射流与自激振荡水射流的优点,提出了自激振荡磨料射流,并从理论上研究了自激振荡磨料射流喷嘴的结构及工作机理。研究表明,自激振荡磨料射流的最大钻孔速度,切割深度分别比前混合磨料射流提高了41%和34%。 相似文献
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基于低压大流量自激振荡射流形成及自激振荡脉冲气体的运动规律,提出了固-脉冲波峰点接触的"滚动摩擦"自激振荡脉冲式天然气管道输送运动形式。分析了下游喷嘴直径、腔室直径、腔室长度和腔室碰撞壁倾角等结构参数对天然气管道减阻增输特性的影响,并确定了较优的自激振荡脉冲腔室无量纲参数。研究结果表明:腔室下喷嘴直径反映自激振荡脉冲射流的过流特性,腔室直径影响自激振荡脉冲射流涡旋配对效果,腔室长度与自激振荡脉冲射流振荡频率及脉动幅值有关,碰撞壁倾斜角直接决定腔室涡漩中心的位置,进而产生周期性高压脉冲射流团的特殊聚能效应。计算后获得的自激振荡脉冲腔室较优无量纲参数为:腔室下游喷嘴与上喷嘴直径比为1.3,腔室长度与上喷嘴直径比为2.4,腔室直径与上喷嘴直径比为6,腔室碰撞壁倾斜角度为120°。 相似文献
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电液伺服阀是某液压伺服控制系统中的一个关键控制元件,但是在实际使用过程中出现了自激振荡现象。通过理论分析和试验研究,结合实际给出了相应的解决方案。系统试验验证的结果表明,改进措施有效,系统性能稳定,工作可靠。 相似文献
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啄木鸟装置可以产生自激振动,这种运动需要依赖摩擦力的作用,从而完成一系列的动作。为了研究啄木鸟装置系统的非线性的复杂运动过程,通过拉格朗日方程对自激振动中线性互补问题进行求解,从而得到啄木鸟装置的运动特性。啄木鸟装置可以通过自身的自激振动,而不需要依赖任何的动力和控制完成周期性的运动。整个连续周期的动态仿真表明其是稳定的周期被动运动,试验样机也验证了仿真的正确性。 相似文献
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Monitoring of OH chemiluminescence through an optical fiber was demonstrated to be a useful method in detecting self-excited
combustion oscillations. OH chemiluminescence intensity detected by the optical fiber showed mostly excellent agreement with
those obtained by high speed CCD camera measurements when combustion oscillations were strong. Symptoms of self-excited combustion
oscillation were also studied in order to predict the onset of combustion oscillation before it proceeded to a catastrophic
failure. For the purpose, we have found and proposed unique measures to tell the onset of self-excited combustion oscillations
based on the careful statistics of fluctuating properties in flames, such as pressure or emission of OH radicals. 相似文献
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为提升小孔节流空气静压轴颈轴承的静、动力学性能,针对轴承间隙的流场特性与轴承的承载力、位移阻抗性能进行分析与优化。采用数值仿真方法分析轴承间隙的流场特性,并在参数设计中消除了气膜流场中的超音速区,以避免微振动;分析轴承气膜的刚度、阻尼性能,并采用ESA-CFD(Engineering Simplification Algorithm-Computational Fluid Dynamics)方法计算轴承振动系统的位移阻抗。结果表明,气膜压力自小孔至外边界逐渐衰减,小孔出口出现激波可导致漩涡流动并引起微振动,微振动形成机制与止推轴承相似。建立优化设计数学模型,以轴颈轴承的位移阻抗、承载力为设计目标,并消除轴承微振动,其中考虑多组偏心率与激励频率的组合。通过优化设计,提升了轴颈轴承的力学性能,相关优化、分析过程可为工程应用中空气静压轴颈轴承的设计提供参考。 相似文献
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Characteristics of self-excited combustion oscillation are experimentally studied using confined premixed flames stabilized
by a rearward-facing step. A new idea to suppress combustion oscillation was applied to the flames. The characteristics of
unsteady combustion were examined, which is driven by forced pulsating mixture supply that can modulate its amplitude and
frequency. The self-excited combustion oscillation having weaker flow velocity fluctuation intensity than that of the forced
pulsating supply can be suppressed by the method. The effects of the forced pulsation amplitude and frequency on controlling
self-excited combustion oscillations were also investigated comparing with the steady mixture supply. The unsteady combustion
used in this experiment plays an important role in controlling self-excited combustion oscillations, and it also exhibits
desirable performances, from a practical point of view, such as high combustion load and reduced pollutant emissions of nitric
oxide. 相似文献
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由于气压传动的优点,由气缸往复直线移动驱动的分度机构应用越来越广,蝶板摆动单向分度机构就是其中之一。通过对蝶板摆动单向分度机构的特性分析,说明了各分度元件的有关尺寸对该分度机构特性的影响。 相似文献
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Effects of semi-floating ring bearing outer clearance on the subsynchronous oscillation of turbocharger rotor 总被引:1,自引:0,他引:1
Semi-floating ring bearing(SFRB) is developed to control the vibration of turbocharger rotor. The outer clearance of SFRB affects the magnitude and frequency of nonlinear whirl motion, which is significant for the design of turbocharger. In order to explore the effects of outer clearance, a transient finite element analysis program for rotor and oil film bearing is built and validated by a published experimental case. The nonlinear dynamic behaviors of rotor-SFRB system are simulated. According to the simulation results,two representative subsynchronous oscillations excited by the two bearings respectively are discovered. As the outer clearance of SFRB increases from 24 μm to 60 μm, the low-frequency subsynchronous oscillation experiences three steps, including a strong start, a gradual recession and a combination with the other one. At the same time, the high-frequency subsynchronous oscillation starts to appear gradually, then strengthens, and finally combines. If gravity and unbalance are neglected, the combination will start starts from high rotor speed and extents to low rotor speed, just like a zipper. It is found from the quantitative analysis that when the outer clearance increases, the vibration amplitude experiences large value firstly, then reduction, and suddenly increasing after combination. A useful design principle of SFRB outer clearance for minimum vibration amplitude is proposed: the outer clearance value should be chosen to keep the frequency of two subsynchronous oscillations clearly separated and their amplitudes close. 相似文献