共查询到20条相似文献,搜索用时 421 毫秒
1.
葛洲坝1号船闸阀门门楣勇气设施原型观测研究 总被引:1,自引:0,他引:1
葛洲坝1号船闸为减弱阀门空化,采用阀门门楣加设掺气挑坎的自然通气措施。经原型观测研究表明:加设掺气挑坎后阀门开启过程中,实现了稳定的自然勇气,声振基本消失。顶缝强空化获得抑制。底缘空化强度减弱,启门力及门后压力脉动亦降低,阀门工作条件改善显著。 相似文献
2.
3.
4.
针对船闸阀门段空化问题,以新建的西津二线船闸为例开展原型观测研究,观测表明:充泄水阀门采用设计阶段阀门模型推荐的门楣体型,原型中实现了门楣自然通气,充泄水阀门双边开启最大通气量分别为0.11、0.17 m3/s。门楣通气抑制阀门段空化效果显著,整个阀门开启阶段,闸顶未听见不通气存在的明显的空化泡溃灭声及雷鸣声;与不通气相比,门楣通气后充泄水阀门双边开启过程中空化噪声强度平均降低60%、82%;充泄水过程中,闸顶声级计在开阀期间所采集的平均噪声分别为68、79 dB;门楣通气后,阀门吊杆振动得到明显改善。防空化措施能够有效保护阀门及阀门段廊道免受空蚀侵害,保障船闸安全高效运行。 相似文献
5.
6.
阀门空化问题是高水头船闸设计中最为关键的技术难题。结合国内外船闸研究及运行经验,在阀门埋深相同的前提下,阀门段廊道体形是影响阀门段空化特性的主要因素,亟需进行不同廊道体形的非恒定流特性研究。依托实际工程,开展模型试验进行 “底扩顶扩廊道体形+反弧门”与“平底顶渐扩廊道体形+反弧门”的对比研究,通过阀门廊道段动水载荷特性及阀门启闭力特性等各项指标的综合对比得出,前者更适合于高水头船闸,但该廊道形式工程量较大,体形复杂,施工要求较高,后期检修维护较困难。综合各种因素,犍为船闸选用“平底顶渐扩廊道体形+反弧门”方案。 相似文献
7.
针对大渡河安谷水电站高水头船闸在阀门开启过程中阀门段极易发生空化的问题,研究提出了采取"阀门后底突扩+顶突扩"廊道体型、门楣自然通气、升坎自然通气和跌坎强迫通气工程措施,可以有效解决其突出的阀门空化的难题. 相似文献
8.
9.
高水头船闸输水阀门的空化和声振是世界船闸建造中的重大技术难题之一,文章提出的门楣通气减蚀措施具有投资省,运行可靠,效果显著的特点,它解决了我国高水头船闸下游水位变幅大,难以采用国外常用的阀门后廊道顶通气减蚀措施的难题。 相似文献
10.
11.
喷水推进器空化监测技术研究 总被引:2,自引:1,他引:1
由于喷水推进船良好的快速性、机动性、高效率和低噪声,喷水推进技术在现代舰船上的应用越来越广泛.但喷水推进器在运行过程中容易进入空化区,影响其推进性能和使用寿命.建立空化监测系统是目前解决这一问题最有效的方法.喷水推进器的空化特性同螺旋桨的有较大差异,目前尚未进行深入的研究.本文分析了喷水推进器的空化特性,阐述了其空化监测的机理,建立了空化监测系统,对喷水推进器空化监测技术进行了研究.空化监测的关键在于选择合适的空化监测参数,选取适当的测量位置,以及采用有效的信号分析处理方法来进行空化特征的提取. 相似文献
12.
阐述了螺旋桨空泡的形成机理,对其产生的噪声及其噪声谱作了分析;阐述了激光空泡噪声的原理,分析了激光产生噪声的机制。两者的比较分析研究,为后者对前者的仿真提供了一定的参考价值。 相似文献
13.
二维水翼型空化流的数值计算(英文) 总被引:2,自引:0,他引:2
In order to predict the effects of cavitation on a hydrofoil, the state equations of the cavitation model were combined with
a linear viscous turbulent method for mixed fluids in the computational fluid dynamics (CFD) software FLUENT to simulate steady
cavitating flow. At a fixed attack angle, pressure distributions and volume fractions of vapor at different cavitation numbers
were simulated, and the results on foil sections agreed well with experimental data. In addition, at the various cavitation
numbers, the vapor fractions at different attack angles were also predicted. The vapor region moved towards the front of the
airfoil and the length of the cavity grew with increased attack angle. The results show that this method of applying FLUENT
to simulate cavitation is reliable. 相似文献
14.
15.
16.
文章在均质平衡多相流模型的基础上耦合输运方程型空化模型,通过求解混合介质的RANS方程、RNG k-ε湍流输运方程以及各相的质量输运方程,采用通用CFD软件—FLUENT数值模拟了水洞中带圆盘空化器航行体模型的定常通气空泡流动,研究了圆形截面闭式空泡水洞中洞壁效应对通气空化数和压力场的影响。得到的阻塞空化数线性正比于圆盘水洞直径比,且与三维圆盘自然空泡流的势流近似解基本一致,分析了洞壁效应作用下空化流场内的压力分布特点,并根据计算结果拟合了一定适用条件下通气空泡长度、最大直径和模型阻力系数的近似公式。 相似文献
17.
18.
This paper presents the numerical analysis of rudder cavitation in propeller slipstream and the development of a new rudder
system aimed for lift augmentation and cavitation suppression. The new rudder system is equipped with cam devices which effectively
close the gap between the horn/pintle and movable wing parts. A computational fluid dynamics code that solves the Reynolds-averaged
Navier–Stokes equations is used to analyze the flow field of various rudder systems in propeller slipstream. The body force
momentum source terms that mimic flow field behind a rotating propeller are added in the momentum equations to represent the
influence of the propeller and its slipstream. For detailed explication of the new rudder system’s lift augmentation and cavitation
suppression mechanism, three-dimensional flow analysis is carried out. Simulations clearly display the mechanism of the lift
augmentation and cavitation suppression. The computational results suggest that the Reynolds-averaged Navier–Stokes-based
computational fluid dynamics reproduces the flow field around a rudder in propeller slipstream and that the present concept
for a cavitation suppressing rudder system is highly feasible and warrant further study for inclusion of the interaction with
hull and mechanical design for manufacturing and operations. 相似文献
19.
Hajime Yamaguchi Hiroharu Kato Kazuyuki Matsuda 《Journal of Marine Science and Technology》1996,1(4):198-208
Sound pressure distribution around a monotone sound source was measured inside a marine propeller cavitation tunnel and compared
with the calculated result by a two-dimensional boundary element method. The measured sound pressure distribution showed some
peaks due to the reflection effect of the tunnel test section boundary. As the frequency increased, the sound pressure distribution
became more complicated, showing more peaks. The tunnel reverberant effect should be taken into account when the noise data
measured in the tunnel are converted into full-scale values. In the boundary element method calculation, the boundary condition
at the acrylic observation window of the tunnel was examined in detail. The calculated sound pressure distribution pattern
in the tunnel transverse section agreed well with the measured distribution when a reasonable boundary condition was adopted.
The boundary element method is an effective method for theoretically predicting the acoustic field inside the cavitation tunnel
if the precise boundary condition is adopted. 相似文献
20.
采用试验的方法研究了不同空化数下水翼叶顶间隙区域漩涡空化流动的发展变化。试验在闭式空化水洞中进行,采用高速全流场显示技术对空化流场进行观测,并采用图像处理技术对试验结果进行处理,提出空化涡模型,阐述了涡空化的发展规律。研究结果表明:随着空化数的降低,叶顶间隙漩涡空化的发展主要经历如下三个阶段:(I)泄露涡内部空化初生阶段:在水翼中部附近产生游离状空化,向下游运动并迅速溃灭消失。(II)叶顶间隙内部附着空化发展阶段:涡空化逐渐发展并向水翼尾缘延伸,空化涡带呈螺旋状非轴对称旋转;叶顶位置压力面中部附近开始出现片状附着型空化,并体现出强烈的非定常特性。(III)射流剪切层内部空化形成阶段:涡空化延伸至水翼下游;叶顶附着空化充分发展,充满间隙并形成射流剪切层空化,和空化涡带共同形成三角状空化结构。 相似文献