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高低齿迷宫式汽封泄漏流动特性研究 总被引:6,自引:1,他引:5
针对汽轮机高低齿迷宫式隔板汽封的复杂结构和轴的旋转效应,采用数值求解三维Navier-Stokes方程技术研究其泄漏流动特性。采用有限体积方法离散Navier-Stokes方程和标准k-ε两方程紊流模型封闭方程组。数值求解方法采用SIMPLE算法,迎风二阶格式求解对流项,迎风一阶格式求解扩散项。研究分析了在相同汽封轴向距离和汽封间隙条件下,三种不同齿数的高低齿迷宫式隔板汽封在不同压比下的泄漏流动特性,并计算了相应的量纲一流量系数。数值模拟结果证明了在相同压比和汽封轴向距离条件下齿数减小会造成泄漏量增加,在相同的齿数条件下,量纲一流量系数随着压比增加而增大。研究工作为工程设计高低齿迷宫式汽封提供了理论依据和技术支撑。 相似文献
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目前国内外电站汽轮机大多采用的是梳齿型汽封,文中研究此种汽封的漏汽问题,应用了马丁公式作为主要研究方法,进行理论推算的同时并进行试验修正,最终推导出可供设计参考的经验公式,以此公式为依据可以比较准确地计算出汽封漏汽量。 相似文献
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汽轮机低压缸轴封能防止空气漏入或蒸汽从汽缸漏出,从而保证凝汽器的真空度。为进一步提高机组的安全经济性,浙江大唐乌沙山发电有限责任公司(下简为乌沙山发电公司)利用检修机会对4台汽轮机低压缸轴封进行了侧齿汽封改造,实现了自密封效果。现对该项目立项进行了技术分析,总结了改造全过程质量管理经验,对新机组建设和同类机组改造有一定参考价值。 相似文献
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针对国内汽轮机组采用的汽封选型,介绍了蜂窝式汽封、布莱登汽封、接触式汽封、侧齿式汽封的性能及使用过程中出现的一些问题. 相似文献
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针对汽封对汽轮机经济性的影响,总结了近年来的汽轮机汽封新技术,分别从结构、原理、性能各方面介绍了常用的几种汽封,并对今后汽封技术的发展进行了展望。 相似文献
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文中阐述了汽轮机停机后汽缸下半汽封齿碰磨的原因,提出了防止汽封齿碰磨的优化措施,即汽缸上半设置冷却室,给机组的安全运行及维护提出了指导性意见。 相似文献
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Chung Kyun Kim 《Journal of Mechanical Science and Technology》1988,2(2):133-139
Analysis are presented for a compressible gas flow across shaft seals. The leakage flow rate is developed analytically for
a sealing gap due to eccentricity, misalignment of a shaft, sinusoidal wavy surfaces for both bodies, thermoelastic deformation
on the edge of the body, and wear on the mating surfaces. A pressure distribution is determined as a power series based on
the simplified nonlinear Reynolds equation. The restriction to exclude the thermoelastic effects was presented. Analytical
results indicate that the thermoelastic distortion may dominate the seal performance when the eccentricity is large and width
of the seal small at high speeds. 相似文献
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基于水力空化相关原理和壅塞管的特性,对壅塞管空化器空化流场特性进行数值模拟研究,确认影响空化器空化效果的因素。通过研究确认,入口压力与入口直径对壅塞管空化器的空化强度有决定性影响。入口压力增大,空化器内压力梯度增大,表明入口压力越大,壅塞管空化器空化效果越好。入口直径增大,壅塞管内最大含气率升高,可在更大范围水体内产生空化泡,进而加强空化效果。在壅塞管空化器内产生比较均匀的气液混合两相流时,沿轴心线方向,从壅塞管中部位置至壅塞截面位置,气液两相流动的马赫数缓慢增大,在压力梯度到达极值时马赫数达到最大,为0.97,接近于1。 相似文献
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Abstract The hard disk drive spindle is one of the critical mechanical components in hard disk drives (HDDs). It has great influence on overall performance, including track density, data-transfer rate, energy consumption, noise, and so forth. Nowadays, HDDs with higher density and speed, larger capacity, and smaller size are under active development. This requires that HDD spindles have fast rotating speed, excellent accuracy, and small size. However, ball-bearing spindles, which are widely used in current HDDs, cannot meet these requirements. HDD spindles supported by oil-lubricated spiral-groove bearings are considered to be a candidate to replace ball-bearing spindles. There is no oil-supply device in the bearing, and the flow characteristics of the lubricant in the bearing have a great effect on the performance of the spindle. In this article, the fluorescent method is used to study the flow characteristics of the lubricant in a spiral-groove bearing. The establishment and recovery of the lubricant film during start/stop of the spindle are observed. The effects of working conditions on the thickness and distribution of the lubricant film are investigated. The influence of oil supply on the performance of the bearing is also studied. 相似文献