共查询到20条相似文献,搜索用时 15 毫秒
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One of the alternative hydraulic fluid is water, which is environmentally acceptable, low-cost and non-flammable. We have designed a new hydraulic test rig and a new water proportional control valve to investigate the tribological and hydraulic behaviour of such water-based systems under pressures of up to 16 MPa and flows of up to 30 lpm. In this work, we present the lifetime performance of all-stainless-steel valve with distilled water being used as the hydraulic fluid. The results show that the water-based valve can operate for more than 10 million cycles under industrial relevant conditions if the water cleanness is appropriately maintained. 相似文献
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空化是影响轴向柱塞泵性能的主要因素之一, 将引起轴向柱塞泵的内部冲击和噪声, 甚至失效等问题。采用Pumplinx建立轴向柱塞泵内部流体域动态模型, 仿真分析了轴向柱塞泵配流盘吸油口卸荷槽和腰型槽内部流场速度、压力及空泡随时间的变化规律。研究结果表明, 空化不仅影响配流盘卸荷槽的高低压过渡区, 而且对配流盘吸油口侧的腰型槽内壁同样会产生严重影响。通过对比斜盘轴向柱塞泵在35 MPa全排量工况下, 耐久性试验过程中出现的配流盘吸油口腰型槽内壁表面金属剥蚀区域, 验证了仿真结果的准确性。 相似文献
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Sung-Hwan Park 《Journal of Mechanical Science and Technology》2009,23(9):2468-2478
For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control
method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause
extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study,
the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics
of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline
in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional
poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation. 相似文献
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《Tribology International》2012,45(12):2013-2021
One of the alternative hydraulic fluid is water, which is environmentally acceptable, low-cost and non-flammable. We have designed a new hydraulic test rig and a new water proportional control valve to investigate the tribological and hydraulic behaviour of such water-based systems under pressures of up to 16 MPa and flows of up to 30 lpm. In this work, we present the lifetime performance of all-stainless-steel valve with distilled water being used as the hydraulic fluid. The results show that the water-based valve can operate for more than 10 million cycles under industrial relevant conditions if the water cleanness is appropriately maintained. 相似文献
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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. 相似文献
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为了提高液压支架的机械控制能力,利用电液换向阀完成支架控制箱动作控制。该文采用流体动力学仿真了电液换向阀的动态特征及流场特性。研究结果表明:当时间到达0.14 s时二级阀芯发生运动,出口流量快速增大至一个峰值状态;随着阀芯到达一个稳定运动状态后,换向阀也达到1013 L/min的稳定出口流量。换向阀在高压大流量系统内工作时将会快速到达峰值压力,产生液压冲击作用并使支架立柱受到破坏。当流体由阀套流至阀芯时因为过流断面的面积会迅速降低,使压力下降4.1 MPa,形成压力集中损失的区域,同时在阀芯的主流道区域还会形成均匀的压力分布状态。从阀口的下游最初进入阀芯的主通道位置时将达到最大流速,等于109 m/s,表明该部位形成了最小的过流面积。 相似文献
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适用于液压支架的比例方向阀代替现有的开关型方向阀,是液压支架智能化的重要组成部分。提出了一款适用于液压支架系统的比例方向阀方案,其兼有手动开关控制模式和电液比例控制模式,建立了其数学模型和仿真模型,分析了其动静态特性。研究表明:主阀进液阀芯位移与输入信号占空比呈线性反比例关系;合理设计反馈槽宽度和进液阀芯面积比可以提高阀芯的响应速度;当仅有液压反馈时,进液阀芯位移仍受控于输入信号,避免了因传感器失效对控制系统造成的灾难性事故的发生;通过增加电反馈与原有液压反馈构成双反馈控制的方式,大幅提高了阀的响应速度、线性度、滞环等特性。 相似文献
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针对液压往复密封的低摩擦、高耐磨、耐高压抗挤出、耐液压油等独特工况条件,采用聚四氟乙烯(PTFE)和碳纤维对聚醚醚酮(PEEK)材料进行填充改性,研究改性PEEK材料的力学性能和摩擦磨损性能,并与填料改性PTFE材料进行比较。通过结构设计和有限元仿真分析,对改性PEEK材料与弹性体材料组合的密封件在不同温度下的密封性能进行了模拟和分析,并通过密封功能试验对模拟分析结果进行了验证。结果发现:质量分数20%PTFE填充改性PEEK材料的摩擦因数最低,且其对金属摩擦副无损伤,更适用于液压往复密封;组合密封能有效克服PEEK材料弹性性能差、安装困难的不足。有限元仿真分析结果表明,组合密封在不同温度下能很好适应42 MPa的压力。密封功能试验表明,组合密封比单一PEEK材料密封的启动摩擦力小、泄漏率低,证明改性PEEK材料可替代聚四氟乙烯和尼龙材料应用在液压往复密封领域。 相似文献
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为了解决传统液压阀块体积笨重、制造工艺繁琐且效率损失大的问题,使用3D打印和流体拓扑优化相结合的方法对液压流道进行优化设计。以入口和出口处压差最小为目标,通过流体拓扑优化对常见的液压阀体T形通道进行优化,得到更加符合流体特性的流道,并设计了可以无支撑进行3D打印的圆角正方形截面形状,进行了3D打印试验,优化后的流道3D打印成形效果较好。利用Fluent进行流体仿真,结果显示,当入口流速在2~5 m/s时,优化后的流道有效避免了气穴的形成,最大压力减小了40%以上,入口和出口处压差减小了28%以上,湍流改善了85%以上,流体性能得到显著提升。 相似文献
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为研究双自由度(2D)伺服阀先导控制阀口处气穴现象的影响因素及对阀芯稳定性的影响,运用Fluent软件中cavitation模型对2D伺服阀矩形先导阀口进行了气穴特性的仿真研究。研究表明,在出口压力低于1 MPa时,阀口处会出现气穴现象,且因气穴指数σ较小,故在弓形感受通道会出现气泡现象,出口压力高于5 MPa时,无明显气泡现象但阀口处的气穴仍然存在;随着入口流速增加,阀口内侧壁和外侧壁处气穴强度和分布范围增加;在出口压力0.1 MPa情况下,随着阀口开度增加气穴现象减弱。结果表明,2D伺服阀正常工作时先导阀口处会产生气穴,对伺服阀阀芯运动的稳定性产生干扰。 相似文献
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In response to technical issues such as the ineffective noise reduction impact of balanced cage and single-seat control valves, the U-shaped noise reduction cage control valve is investigated and developed. In addition, its equal percentage flow properties and noise reduction impact are good, allowing it to effectively minimize the noise created by the change of fluid parameters of medium such as vapor, gas, and gas-liquid two-phase flow. The flow coefficient and flow properties were analyzed. The noise features of the medium air flow at small and large openings of 30% and 85% are simulated and analyzed, respectively. The pressure, velocity, and temperature of the inlet and outlet air, as well as the sound intensity maximum and sound power level maximum, are also analyzed with the opening curves. A small opening of 30% was selected, and the noise characteristics of cavitation generated by the medium water flow were simulated and analyzed. Together with the pressure and temperature change curves of the incoming water, the volume maxima and density minima of water are studied. The maximum sound intensity and sound power level of water are analyzed using the pressure and temperature curves of inlet water, as well as the cavitation coefficient and the degree of opening. The results of the trial for the pressure resistance of the valve body and the trial for the valve seat seal indicate that both the valve body strength and the valve seat seal meet the specifications. Comparing the noise trial results and simulation results reveals that the sound intensity and sound power level assessed by the trial and simulation are comparable, and the noise reduction impact of the control valve is positive. 相似文献
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水压柱塞泵(马达)配流盘的研究与仿真 总被引:2,自引:0,他引:2
介绍了柱塞泵 (马达 )配流型式的发展 ,对水压轴向柱塞泵 (马达 )力矩全平衡型配流盘进行了分析。通过数字仿真研究了配流盘结构对柱塞腔内压力的影响 ,发现减振槽及其过流面积对气蚀的产生有直接的作用 ,合适的吸入口压力或背压可减小泵或马达发生气蚀的可能性 相似文献