水轮机调速器系统充油方式对主配压阀可靠性的影响分析

选择合适的水泵水轮机调速器系统充油方式对提高主配压阀可靠性极为重要。鉴于此,针对调速器系统检修后充油方式的选择及影响进行了分析,并介绍了调速器系统充油方式优化与油质污染控制相结合提高主配压阀可靠性的技术措施。     

非接触式主配压阀位移测量装置研究及应用

该文介绍了主配压阀位移测量在水轮机调速系统中的重要作用,分析了主配压阀的控制原理,提出了一种非接触式主配压阀位移测量装置,并对其结构形式及功能进行了介绍。该装置的研究可有效减少震动影响、消除磨损、方便安装,为同类产品的设计提供参考。     

具有分段关闭功能的主配压阀研究及应用

该文介绍了主配压阀、分段关闭装置的工作原理,分析其分开布置的缺点。提出了具有分段关闭功能的配压阀的结构组成,并对其功能进行介绍。该型主配压阀的研究可有效方便安装、降低系统压降,并为同类产品的设计提供参考。     

卡特彼勒3066发动机润滑系统及其使用保养注意事项

我们常见的一些工程机械发动机上都配有机油冷却器。在这些发动机中,为了保证冷车起动时不因温度过低、机油流动受阻而造成主油道和润滑油道失油,在冷却器机油人口处一般都设有旁通阀,以便在冷天起动时通过旁通阀短时间地向润滑油路供油。以卡特彼勒3408发动机润滑油路为例,当机油因冷却器受阻而压力升高时,油压通过旁通阀活塞使旁通油路打开,机油则通过旁通油路进人主油道。在卡特彼勒320型液压挖掘机所配的3066发动机上,则没有冷却器旁通阀（见附图）。3O66发动机润滑油路示意图1增压器2．配气机构3．供油管4燃油泵5．主油道6．正…     

外置式主配压阀用自动复中装置研究及应用

该文介绍了某进口主配压阀的工作原理,分析主配压阀掉电关机对电网稳定的影响。提出了一种外置式主配压阀用自动复中装置,并对其原理、功能进行介绍。该装置可不改变现有主配压阀内部结构,实现水轮机调节系统电源消失时主配压阀保持在中位,以保持接力器开度和水轮机有功功率不变,有利于电网的安全稳定。     

水轮机调速器电液随动系统的研究

介绍了一种适合于水轮机调速器中使用的主配压阀-旋转配压阀,建立了旋转配压阀-接力器动力系统的非线性数学模型。并设计了一个传统的PID控制器,对调速器电液随动系统在三种负载条件下的阶跃响应进行了仿真研究。     

主配压阀响应速度特性仿真研究

该文利用液压仿真软件建立了水轮机调速系统主配压阀响应速度分析模型,并对搭叠量、控制活塞面积、阀芯阀套径向间隙对响应速度的影响进行了仿真研究.结果表明:主配压阀响应速度与搭叠量、控制活塞面积成反比,与阀芯阀套径向间隙成正比.最后指出在保证主配压阀静态特性的前提下,可通过减少搭叠量与控制活塞面积来提高其响应速度.     

水轮机调速器主配压阀材质的对比摩擦试验

为合理选择水轮机调速器主配压阀活塞衬套的材料,对两组具有代表性主配压阀材料的摩擦学性能进行了对比.采用摩擦磨损试验机测量了不同条件下两组材料的磨损量和摩擦因数,利用扫描电子显微镜对试样的磨损表面作了观察与分析.给出了评价摩擦性能的统计分析参量,并探讨了转速、压力、润滑条件对主配压阀摩擦特性的影响.通过分析对比试验结果,给出了主配压闽材料的合理选择方案.     

某双阀芯电液比例多路阀主阀进口节流流场及阀口压降特性研究

以某系列双阀芯电液比例多路阀为研究对象,采用CFD流场仿真技术和PIV可视化测速技术对不同阀口开度和流量下的主阀沿进口流道、节流口、阀腔的流场进行了流体仿真和试验可视化研究。应用Fluent软件仿真研究了主阀进口节流流场分布并得出阀口压降特性;采用PIV试验研究的手段对流场分析结果加以验证,应用2D-PIV技术获得主阀腔内部一个截面上的流场分布,并通过相似理论计算得出阀口压降特性。CFD流场仿真和PIV试验结果表明：该双阀芯电液比例多路阀主阀出油环形腔内会形成较大旋涡,且阀口开度和流量对主阀进口节流内部流场结构和阀口压降特性有重要的影响。研究结果对定性分析双阀芯电液比例多路阀主阀内能量损失和噪声、主阀的结构和流道的设计以及优化具有重要实际意义,为CFD技术和PIV技术在双阀芯多路阀领域的应用研究提供了参考。     

阀配流水压柱塞泵的回冲射流及其容积损失

为揭示水压柱塞泵配流阀对泵容积效率的影响程度,设计了阀配流柱塞泵可视化实验装置。通过高速摄像系统清晰观测到柱塞泵中回冲射流现象及形态特征。以阀芯瞬态位移、泵腔压力实测数据为边界条件进行配流阀动网格流场仿真,并进行瞬时流量积分,获得了排水阀回冲射流引起的柱塞泵容积损失数值。结果表明:在1500 r/min转速下,回冲射流时长占柱塞排水周期的30%,约为6 ms,阀芯存在多次振荡且伴随着射流空化;回冲射流造成泵容积效率的损失约为5.3%。     

低压安全阀全开流量偏低的原因分析与优化改进

闭式液压伺服系统在工作过程中液压油温度升高、体积膨胀，设置低压安全阀是为了防止伺服系统低压油路压力升高破坏液压系统。针对某型号低压安全阀产品全开流量低于指标要求的情况展开理论计算和仿真分析。根据CFD仿真得到的流场压力云图，找出了全开流量偏低的原因——阀芯爪部倒角偏小，证明了增加阀芯爪部倒角可提高全开流量，并最终提出了合理的优化方案。经对比试验验证，优化改进方案可行，确有实用性和可操作性，该问题得到解决。     

Hydrodynamic characteristics and optimization design of a bio-inspired anti-erosion structure for a regulating valve core

Cavitation is the main failure mode of coal liquefaction regulating valve, which seriously limits the service life of the regulating valve. In order to restrain cavitation in the regulating valve, a bio-inspired anti-cavitation structure inspired by the red willow of valve core is proposed. Distributions of pressure, velocity and vapor volume fraction in the bionic valve under different openings (30%, 40%, 50%, and 60%) and inlet pressures (2.0MPa, 3.0MPa, 4.0MPa, and 5.0MPa) are discussed. In addition, the parameters of bionic valve structure are optimized using NSGA-II algorithm, the field synergy principle is applied to evaluate the flow field optimization in the bionic valve. The results show that the cavitation area and cavitation length in these bionic structures are reduced significantly compared with the traditional smooth structure. And the anti-cavitation performance of the trench structure is the best, when the inlet pressure is 3 MPa and the opening is 30%, the vapor volume is 0.10 mm³, the vapor volume is reduced by 98.07% compared with traditional smooth structure. Convex hull structure is the second. When the inlet pressure is 5.0 MPa, the vapor volume of the traditional smooth structure is as high as 148 mm³, and the vapor volume of the convex hull structure is 35 mm³, the vapor volume of the trench structure is 19 mm³. Through the field synergy theory to evaluate the internal flow field, it is found that the effective viscosity coefficient in the traditional smooth structure regulating valve varies from 0.7 to 1.2, that of the bionic trench valve changes from 0.1 to 0.5, both the flow resistance and energy consumption in the trench structure valve are reduced. It is proved that the bionic trench structure of the valve core can effectively improve anti cavitation performance and optimize the internal flow resistance of the flow field, which is of great significance to the optimal design of the control valve.     

机油泵限压阀工作压力反馈控制方式研究

本文阐述了机油泵限压阀工作压力的两种不同的反馈调节方式,并通过试验分析不同的限压阀工作压力反馈方式的发动机机油压力分布规律,总结出机油泵限压阀采用主油道机油压力反馈控制,发动机高速运转时的主油道机油压力受机油温度和油道阻力影响小,机油压力更加稳定,能够对发动机主油道机油压力实施精确的控制,特别是对发动机低温运行工况机油压力过高和旧机油滤清器机油压力过低有很大改善。     

射流管伺服阀通油冷却建模与仿真分析

射流管伺服阀在高温环境中易发生共振、卡滞、零漂等故障,提出在阀体中增设通油冷却以实现冷却隔热的目的,保证其在高温下正常运行.以某型射流管阀为载体,建立了包含冷却油路、射流管油路及主阀油路的三维流-固-热仿真分析模型.分析了正常工况下冷却油路的压降特性和热防护特性,讨论了4种油路故障状态下的伺服阀热场分布特征.结果表明,...     

Experiment and simulation study on cavitation flow in pressure relief valve at different hydraulic oil temperatures

Hydraulic oil is the “blood” of hydraulic system, its high temperature in low-pressure hydraulic system would promote the development of cavitation and cause severe erosion of pressure relief valve. The influence of high oil temperature on the distribution of pressure field, velocity field and vapor volume fraction are discussed experimentally and numerically. The results show that with the increasing oil temperature, the viscosity of the oil decreases, and the flow rate increases, resulting the decreasing pressure at the orifice. Higher oil temperature promotes the occurrence of cavitation in the pressure relief valve, wider low-pressure zone could be found and cavitation bubble developed more fully and towards the valve core head. When the oil temperature increases from 303 K to 353 K, the cavitation intensity rises more sharply, but the growth rate of cavitation intensity increases firstly and then decreases with the increasing input pressure. Furthermore, based on the field synergy theory, the flow resistance and energy dissipation under different oil temperatures are evaluated. Both of large viscous dissipation and effective viscosity coefficient are mainly concentrated at the orifice, which are all effected by the oil temperature, so as to the characteristics of cavitation flow. The average field synergy cosine angle and the average viscosity coefficient decreases gradually with the increasing oil temperature, while the average vapor volume fraction increases. The energy dissipation is reduced by 3.3 × 10⁷ (W m⁻³) while the hydraulic oil temperature increases from 303 K to 353 K. Appropriate hydraulic oil temperature could provide favourable working conditions for the pressure relief valve which is beneficial for extending the hydraulic system's service life.     

位移-电反馈型插装式比例节流阀主阀流场数值模拟分析

为掌握位移-电反馈型插装式比例节流阀主阀腔内流体流动区域的流场分布情况等基础问题,将CFD技术应用到该阀主阀内部三维流场分析中.应用数值模拟技术进行了三维网格划分,得到了位移-电反馈型插装式比例节流阀在两种不同开口度下流体的压力、流速及流线情况,对流场仿真结果进行了对比分析.研究结果揭示了该阀主阀腔内的流场分布情况,给...     

某型垃圾车后门非正常开启故障排查与原因分析

针对某型垃圾车后门非正常开启故障,采用现场测试、试验及理论分析的方法,对造成该故障的原因进行排查与分析。经分析得到由于多路阀受回油量影响,内部回油容腔压力升高,致使后门锁紧液压锁非正常开启,后更换后门锁紧联阀芯解决了该问题。     

Influence of the flow area around the ball valve on the flow characteristics of the injector control valve

The increase in common rail pressure can lead to increased cavitation inside the injector, resulting in degradation of injector performance and reduced life. The paper investigates the effect of the pressure block structure parameters (initial flow area around the ball valve) on the velocity field, pressure field, fuel gas phase volume fraction and drain rate of the control valve. The relationship between the initial flow area around the ball valve on the cavitation strength and unloading rate inside the valve was revealed. The results show that both the reduction of the flow area around the ball valve and the increase of the cavitation intensity inhibit the rate of oil discharge from the control valve. The reduction of the fuel flow area inhibits the expansion of the low-pressure region (0–1 MPa) within the flow layer, thus limiting the development of cavitation. The reduction of the cavitation area increases the fuel flow rate, however, the increase in flow rate increases the cavitation phenomenon, and these changes form a cycle (Reviewer 5. comment 2). The increase in cavitation inhibits the control valve pressure relief rate more significantly than the decrease in the initial flow area around the ball valve. Based on this, a stepped-pressure block model is proposed. The stepped pressure block model can effectively reduce the cavitation strength near the seal and enhance the oil discharge rate of the control valve. The study can provide a reference for the engineering optimization design of high-pressure common rail injector control valves.     

多腔体串联电流变阀的设计与特性

设计出一种多腔体串联结构的电流变阀,该阀设有若干个带有集散式轴流孔的平行电极,腔体高度和数量可调,从而可满足较大范围的调速要求。推导了电流变阀压差公式,明确了压差与场强、流量和腔体高度的关系。利用Fluent软件仿真分析了电流变阀的流体压力分布情况和流动情况。设计制作了电流变阀的系列样机,进行了验证试验和对比试验。结果表明：圆板式电流变阀腔体高度在1mm以下性能较好;串联结构能有效提高电流变阀对压差和流量的连续调节能力。