共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
5.
在定常流动下混流式水轮机叶片横向振动特性分析 总被引:5,自引:1,他引:5
使用一般壳体理论及ALE描述下叶片近壁区流动控制方程,在正交流线坐标系中建立了描述混流式水轮机叶片振动的一般方程,并将叶片在流向与展向的振动对横向振动的影响表示为参数函数,构造出描述叶片横向振动的Mathieu方程,从而可利用数学上熟知的Mathieu方程的特性分析叶片的横向振动。 相似文献
6.
7.
8.
雪花型层板结构冷却特性的数值模拟研究 总被引:1,自引:0,他引:1
设计了两种孔间距比的雪花型层板冷却结构,采用有限体积法求解三维可压缩的N—S方程对其内部流动和换热进行了数值模拟。网格划分采用非结构化网格,湍流模型为Realizableκ-ε双方程模型,近壁处湍流采用壁面函数法处理,采用SIMPLE算法求解速度与压力的耦合。计算获得了这两种冷却结构内部各气流参数的三维分布及流动阻力特性和换热特性。结果表明,层板内部的流场结构十分复杂,射流冲击后在扰流柱前反卷形成驻涡,呈雪花形分布的扰流柱阵列的存在对气流起到了较好的分流和引导作用,使气流在冷却通道内分布更为均匀,改善了层板换热的均匀性。数值计算对于改进层板内部结构优化设计有着重要的实际应用价值。 相似文献
9.
高浓度水煤浆的流变特性与壁面滑移效应试验研究 总被引:1,自引:0,他引:1
在水煤浆综合输送试验装置上,采用直径分别为25 mm、32 mm、40mm和50 mm的圆管,对质量分数为65.3%、67.1%和68.2%的高浓度水煤浆进行了流动特性和滑移特性试验研究.从合理假设的滑移速度模型和流动结构出发,得出滑移速度和真实流变特性的确定方法,获得了不同浓度和管径下试验水煤浆的滑移速度及真实流变特性.结果表明:所采用的滑移速度模型能很好地描述所试验水煤浆的宏观滑移流动规律;煤浆浓度较高时,呈现显著的非牛顿流体特性,壁面滑移效应显著;壁面滑移效应与煤浆的真实流变特性关系密切,两者共同支配管内流动,对流动特性影响显著. 相似文献
10.
在综合流向微槽表面流动及传热特性的基础上,结合涡轮叶冷却通道内的流动和换热特性,提出了将流向微槽表面应用于涡轮叶片的冷却通道,分析研究流向微槽的影响,以期为涡轮叶片的冷却寻找更有效的技术。 相似文献
11.
通过对发动机气道内气体流动过程的相似分析,在雷诺Re准则数足够大的前提下,非定性准则欧拉Eu数和相似不变量无因次涡流NR保持不变。这就证实通过稳流试验来测量气道的流通性能是可行的。通过数理推导,评价参数流量系数μσ真实就是欧拉Eu准则数的一种表现形式。 相似文献
12.
13.
14.
15.
16.
为研究锥阀空化现象,运用ANSYS Fluent流体力学有限元计算软件,分析锥阀在内流和外流两种情形下的流场,得到锥阀在内流和外流两种流动方式下空化区域0~3s内气体的体积分数。计算对比发现,在液体流速和压力的突变区域空化现象明显,外流较内流空化区域大,空化程度比内流严重。为降低空化现象对锥阀型腔造成的损伤,优化锥阀型腔阀芯结构,优化模型1可避免内流时空化的发生,优化模型2在内流和外流情况下均能有效避免空化的发生,优化模型2的结构形式更为合理。研究成果可为锥阀设计提供参考。 相似文献
17.
Bo LIU Weimin HOU Changyou MA Yangang WANG Qiang ZHOU 《Frontiers of Energy and Power Engineering in China》2008,2(4):448-452
The dynamic pressure measurement device and test technology are described in this study. The tip clearance unsteady flow development
from the inlet to the outlet of an axial-flow rotor was revealed by analyzing pressure frequency spectrum acquired from measuring
the unsteady pressure field of the tip endwall. The experiment provides test basis for thoroughly understanding the tip clearance
unsteady flow and building interaction models of tip clearance flow and main flow.
__________
Translated from Compressor, Blower & Fan Technology, 2007, (5): 12–15 [译自: 风机技术] 相似文献
18.
19.
An experimental study on the shape of a single bubble similar to those observed in a horizontal plug/slug flow was performed using visual observation and conductance probes. The results indicated that the shapes of the bubble nose and the bubble body depend on the Froude number defined by gas/liquid mixture velocity, whereas the shape of the back region of the bubble depends on both the Froude number and bubble length. The photographic images showed that the structural feature of the bubble head is related to the motion characteristics of the bubble. The transition from plug flow to slug flow occurs when the tail of the bubble changes from a staircase to hydraulic jump pattern with the increasing of the Froude number and bubble length. © 2007 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(5): 276– 285, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20161 相似文献
20.
Experimental Studies on The Mechanism and Control of Secondary Flow Losses in Turbine Cascades 总被引:2,自引:0,他引:2
This paper summarizes the results of the authors' 4 year experimental studies on the secondary flow losses in turbine cascades. Cascade wind tunnel experiments were carried out concerning the influence of aspect ratios, incidence, turning angles and outer endwall divergent angles in order to unveil the evolution mechanism of secondary flow losses in turbine cascades without end clearance. Some methods for controlling the secondary flows are investigated including the blade leaning, blade cambering, endwall convergence and leading edge extension at two ends of the blade. 相似文献