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杨华勇, 冀宏, 傅新
机械工程学报,2003,39(6):13~17,-0001,():
-1年11月30日
非全周开口滑阀是液压阀的基本结构形式之一,其阀口是在阀芯凸肩圆周上均布若干不同形状的节流槽,用于获得不同流量控制特性。随着阀口开度变化,阀口节流面的位置、形状和射流角都会随之变化,因而传统理论计算方法无法准确计算压力流量、液动力特性等。采用计算流体动力学(CFD)方法,针对两种典型节流槽形式的滑阀进行了三维流场仿真分析研究,获得了不同流动方向下阀口全行程压力流量和液动力特性,并与试验测量结果进行了比较,两者吻合良好;分析比较了流场计算和理论公式计算结果。研究发现在特定的阀口开度范围内,液动力会使阀口趋于开大。此项研究对于非全周开口滑阀压力流量、液动力等性能预测以及减小阀驱动力具有重要意义。
非全周开口滑阀, 流场仿真, 稳态液动力
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杨华勇, 周华
机械工程学报,2002,38:96~100,-0001,():
-1年11月30日
纯水液压利用过滤后的自然水作为液压系统的压力工作介质,可以避免环境污染和火灾危险,具有价格低廉、清洁卫生等优点。阐述了水介质特性引起的润滑与密封、摩擦与磨损和腐蚀与气蚀等关键技术问题。介绍了陶瓷/陶瓷和增强塑料/不锈钢在水中的摩擦学特性研究结果,确定了陶瓷材料与增强塑料在水中的主要磨损机理。通过盐雾试验评价了热处理工艺对不锈钢腐蚀特征的影响。提出了在纯水液压泵中气蚀初生伴随着低频压力脉动现象。
纯水液压, 润滑与密封, 摩擦与磨损, 腐蚀与气蚀
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【期刊论文】Simulations and experiments for two new kinds of floatation cyclones with natural inlet air
杨华勇, Yang Jian*, Yang Huayong, Xu Bing
,-0001,():
-1年11月30日
A novel structure floatation cyclone with natural inlet air has been designed, and its structural characteristics and floatation principle have been analyzed. Simulations of the velocity and pressure distributions within the flow field of the floatation cyclone have been carried out using Navier Stokes equations and fluid mechanics of two-phase. Based on the flow characteristics of the coal-water slurry, reasonable boundary conditions are decided and the equations are modified, so that the final equations can describe the real flow state of the flow field of the floatation cyclone. The boundary surface position between float coal and tailings is determined and there is an air cylinder in the central region of the floatation cyclone. The research reveals the floatation mechanism of the floatation cyclone. The floatation results can be greatly improved by regulating the structural dimensions of cyclone. The experimental results show that the floatation cyclone is very effective for the floatation of fine coal grains.
Floatation cyclone, Natural inlet air, Simulations, floatation mechanism, floatation of fine coal grains
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【期刊论文】Research on materials of piston and cylinder of water hydraulic pump
杨华勇, Yang Huayong, Yang Jian and, Zhou Hua
Industrial Lubrication and Tribology Volume 55. Number 1. 2003. pp38-43.,-0001,():
-1年11月30日
In this paper, experiments were carried out to study the friction and wear performance for the materials of piston and cylinder in a water hydraulic axial piston pump. The matching of 940 stainless steel circle with F102 engineering plastics block and 940 stainless steel circle with Al2O3 ceramic block were also studied. The wearing capacities were calculated by theoretical formulae based on the grinding crack widths. When pure water is used as hydraulic transmission medium, it is better to use ceramic with engineering plastics as matching materials for the piston and cylinder of water hydraulic axial piston pump. The experimental results have provided a theoretical basis for selecting the matching materials of piston and cylinder.
Water,, Pumps, Cylinder, Wear
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杨华勇, 范明豪, 周华
机械工程学报,2002,38(8):17~21,-0001,():
-1年11月30日
高压细水雾灭火系统是采用纯水液压技术的新型灭火装置,县有无环境污染、灭火迅速、用水量少和水渍损失极小等优点,是目前国际上推祟的哈龙替代系统。运用轴对称射流边界层动量积分法。对系统关键执行元件一直射式雾化喷嘴的内部流动进行分析,对边界层厚度δ和加速因子K这两个内部流动参数进行考查;同时对一些与灭火效果有关的外部雾化特性参数如出口速度和雾滴平均粒径SMD等进行分析,得出压力是影响外部雾化特性参数的最关键因素。认为8~9 MPa是所设计喷嘴的最低稳定雾化工作压力区域。同时,喷嘴结构参数收缩角α、收缩段长度lld对内部流动参数、外部雾化特性参数均有影响,但不明显。试验验证了上述分析结果,优选出了适合的喷嘴内部结构。
细水雾, 灭火, 喷嘴, 雾化特性
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