共查询到19条相似文献，搜索用时 171 毫秒
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陈志兵 《江西电力职业技术学院学报》2014,(1):20-21
介绍了某厂#6机组在检修过程中,针对A电动主汽门由于阀座与阀瓣密封面间存在间隙造成内漏所采取的修复措施。其中创新地提出并采用了单阀板楔形闸阀内部锥度的测量方法以及确定阀瓣车削基准面的方法,最终解决了单闸板楔形阀门锥度不符的技术难题,不仅节省了大笔更换阀门的开支,而且为以后同类型设备出现类似缺陷提供了解决方法。 相似文献
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本文根据减振器液压阻力特性、液压阀结构特点及阀控装置弹簧功用等技术要求,进行了液压阀阀控装置圆柱螺旋压缩弹簧的设计计算。 相似文献
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《武汉工程职业技术学院学报》2017,(4)
数字阀是数字控制系统中的重要元件。结合喷水织机水压系统的工作特性,设计了直控式数字阀,详述了该阀的结构和工作特点,在此基础上,对调节喷水流量的数字阀的动态特性、流量特性进行了仿真研究分析,其结果可为喷水织机实现数字化控制提供参考。 相似文献
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李永法 《河南科技学院学报》2009,37(2):52-55
给出了电液伺服阀综合实验台的设计思想和技术指标,详细介绍了液压源和电液伺服阀测试系统在硬件组成结构中的功能和原理．着重分析了软件的设计结构、功能框图以及原理．实践表明,本系统具有综合能力强、测试精度高、使用方便的特点,可以为电液伺服阀的检测、维护和故障分析提供简便、有效、快捷、可靠的自动测试平台。彻底解决了机械式检测设备的检测手段落后、工作效率低的现状．本系统具有一定的现实意义、战略煮丈和广阔的发展府用前景． 相似文献
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新型压力控制阀的研究 总被引：1，自引：0，他引：1
本文针对现有压力伺服阀的不足之处,利用毛细阻尼管的调压原理和滑阀阀芯的双自由度运动设计制造了一个种新型差压式液压控制阀,该阀具有结构简单,抗污染能力,成本低等特点,并能实现数字控制。 相似文献
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为提高重介质管路平板闸阀的使用寿命,针对重介质管路的特点,改进了平板闸阀的结构,并利用ANSYS有限元分析软件,建立了阀体和闸板的流体动力学分析和结构应力分析三维模型,数值模拟分析它们的受力状况及边界条件,并对结构改进前后的受力进行了对比分析,验证了设计的可靠性。 相似文献
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《浙江大学学报(A卷英文版)》2016,(6)
目的:大型的桁架结构或空间刚架结构可以认为是用中空单元组合而成的宏观结构,在结构初步设计时,如何设计排布中空基本单元以满足结构的性能要求是设计的关键。本文旨在探讨夹层平板结构,在给定竖向变形控制指标后,如何使用简化的方法快速设计各层中空基本单元的尺寸和空隙程度。创新点:1.对于水立方这种复杂的空间多面体网格结构,本文将其理想化为连续的中空介质,利用微观力学中的均质化分析方法,将结构分解为多个基本单元(RVE)进行分析,从而推导出结构性能指标与单元参数之间的关系。2.对于大跨度平板结构,本文提出一种基于RVE重复叠加组合的设计方法,并利用有限元法对该方法进行检验。方法:1.对夹层平板结构的弯曲特性进行理论分析,根据Kirchhoff-Love理论,得到板弯曲刚度与各层的截面惯性矩之间的关系;2.通过理论推导出结构弯曲刚度(图3)、材料使用量(图4)随层厚度和层密度的变化关系;3.从基本单元出发,利用均质化分析方法分别对中空立方体(图5)和空间桁架结构(图6)进行分析,得到结构抗弯刚度随单元中空程度和距截面中性轴距离的函数关系(图7和8),进而推导出结构参数化设计的拟合公式;4.利用该设计公式,针对一个90 m×90 m×2.5 m的平板结构,以跨中挠度为跨度的1/500为设计指标,分别设计由两种基本单元组成的夹层平板结构,并将结构挠度的有限元计算结果与设计指标进行比较(图12)。结论:1.本文提出的利用中空单元组成的夹层平板结构的设计方法,通过优化设计中空单元的各项参数,可以在保证性能指标的同时最大化降低结构质量,得到最优刚度质量比。2.本设计方法和有限元法得到的结果之间差异非常小,说明该设计方法准确可靠。 相似文献
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Jin-yuan Qian Bu-zhan Liu Zhi-jiang Jin Jian-kai Wang Han Zhang An-le Lu 《浙江大学学报(A卷英文版)》2016,17(1):54-64
The pilot-control globe valve (PCGV) is a novel globe valve with a piston-type valve core and a small pilot valve. It can utilize a pressure difference to control the state of the main valve by the pilot valve. In this paper, a mathematical model of PCGV is established and a computational fluid dynamics (CFD) method is used to numerically simulate its flow and cavitation characteristics. Analysis of the pressure difference between the upside and downside of the valve core and comparison with similar previous work increase the reliability of the simulation. Then an analysis of flow and cavitation characteristics is carried out with three comparisons: a comparison between opened and closed states, a comparison between different inlet velocities, and a comparison between different valve core displacements. The results demonstrate that the vapor volume fraction reaches its peak point at the valve seat near the outlet tube, and that a higher inlet velocity or smaller valve core displacement can cause greater cavitation damage. This study can help further design work for optimization and engineering applications of PCGV. 相似文献
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This paper has introduced the developments of water hydraulic axial piston equipments.According to the effects of physicochemical properties of water on water hydraulic components,a novel valve plate for water hydraulic axial motor has been put forward,whose moment exerted by the fluid field between valve plate and bearing plate is balanced entirely.The material screening experiment of valve plate is done on the test rig.Through numerical simulation the effects of some geometry parameters on the performance of water hydraulic motor have been studied.The silencing grooves on the valve plate in water hydraulic motor can reduce the pressure shock and the occurrence of cavitation effectively.It is evident that the appropriate structure should change the wear status between matching paris and reduces the wear and specific pressure of the matching pairs.The specimen with the new type valve plate is used in a tool system. 相似文献
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In this paper,a new pressure reducing valve(PRV) with an orifice plate is proposed.The main objective is to explain the mechanisms of pressure reduction and energy conversion in the new PRV.A numerical simulation method was used to investigate the PRV internal flow field and to analyze the throttling effects of the orifice plate and the transform of thermal parameters as outlet pressure,outlet temperature,velocity,and superheat.A structure improvement method for the valve body and orifice plate is put forward to reduce energy loss.The governing equations for internal flow numerical simulation are composed of the continuity,momentum,energy and k-ε transport equations,based on isotropic eddy viscosity theory.Different valve plug displacement models were built to describe the double throttling process.Our analysis shows that the steam pressure drops twice and the degree of superheat increases.There are also lots of eddies which clog the flow channel and disturb the steam flow in the valve cavity after the valve plug and the outlet cavity.After modifying the structure,the numerical results show a better performance of steam flow. 相似文献
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设计了一种应用于传统非可变配气正时的发动机进气系统的固定式单向阀.将该阀安装于发动机气缸体与化油器之间,在中低转速下可阻止已进入发动机气缸内的混合气发生倒流现象,从而能有效地降低传统发动机的燃油消耗率.介绍了单向阀簧片的3种运动形式和对应的影响因素,分析了簧片的设计要求,重点研究了簧片的运动规律,建立了所设计的单向阀簧片的运动微分方程式,并运用Matlab编程求解出簧片的理论固有频率,为单向阀的簧片的形状和限位板高度等的设计提供参考和依据. 相似文献
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The power of hydraulic piston engines is much affected by the on-off valves which control the fuel injection of the piston assembly. Therefore, the opening time of the seat valve used as the on-off valve is optimized by minimizing the axial flow forces on the spool. A damping sleeve with orifices is proposed to change the valve internal geometry. Experimental and numerical investigations of the flow forces acting on the spool with and without the proposed damping sleeve are carried out to identify the differences in the flow field and to minimize the forces’ effect. The simulated results fit the experimental results well. Both results show that the proposed damping sleeve affects the pressure distribution along the spool cone surface and the jet stream direction significantly. The effects of the orifice’s width, height, and relative sleeve installation positions on the flow field and cavitation are assessed using simulation methods. As a result of the flow field changing, the damping sleeve can reduce the flow forces significantly and even reverse the forces’ direction at the cost of a little flow loss. The opening time of the seat valve can be reduced by 31% to 0.67 ms by using the proposed damping sleeve. 相似文献
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电动截止阀是流体输送的重要元件.阀的传统设计方法很少从流体角度对其流道进行设计,其流阻系数比较大,容易造成局部压力损失.流体介质通过阀口时,流动方向发生变化,可能产生诸如局部涡流、空化、水锤和死水区等水流现象及湍流脉动噪声,对阀体有很强的破坏性,降低阀的使用寿命.基于RAN-S方程组和RNG k-ε湍流模型,利用CFD技术对全开启状态下的电动截止阀的内流道进行三维的湍流数值模拟,获得其总压图、速度矢量图、湍动能强度图.通过数值模拟,可以直观地显示阀的内流道中流体的流动过程.改变进出口段流道的长度、曲率以及阀杆在流道中的布局等,进出口的压力差相对于未改进前减少30%左右,速度突变区域明显缩小,局部涡流现象消失,湍动能强度也降低了15%左右. 相似文献
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结合水介质的理化特性,论述了水压节流阀研制中的关键技术,并设计了一种适用于水介质的中高压节流阀,对该阀主要部件的材质、结构形式、动力学特性等进行了分析和计算。 相似文献
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座椅是影响汽车安全性的重要部件，汽车座椅安全性设计的目标就是尽可能避免座椅安全功能失效情况的发生。在讨论汽车座椅安全性设计主要内容的基础上，分析了有限无法在座椅安全性设计中的应用，并举例说明采用有限元法进行座椅安全性设计的一般过程，对汽车座椅的安全性设计有指导意义。 相似文献