前置级冲蚀磨损对射流偏转板伺服阀的影响

射流偏转板伺服阀前置级油液高速流动时,油液中的颗粒物会对伺服阀前置级产生冲蚀磨损导致伺服阀的性能下降。采用数值仿真的方法对冲蚀磨损前后射流偏转板伺服阀前置级流场进行计算,通过曲线拟合得到两接收孔压差与偏转板位移的关系;将其与射流偏转板伺服阀的AMESim模型结合分析冲蚀磨损前后伺服阀位移及空载流量的变化。结果表明:冲蚀磨损导致射流偏转板伺服阀前置级两接收孔压差减小;在相同的输入条件下射流偏转板伺服阀阀芯位移减小,空载流量降低。     

射流管电液伺服阀滑阀冲蚀磨损特性分析

射流管伺服阀的油液被污染后,其中的颗粒在高速射流下会对滑阀产生冲蚀磨损,从而影响伺服阀的工作性能.针对上述问题,建立射流管伺服阀的AMESim模型;结合计算流体动力学与冲蚀磨损理论,建立滑阀的冲蚀磨损数学模型.通过有限元仿真软件,模拟颗粒对滑阀的冲蚀磨损;基于射流管伺服阀的AMESim模型,分析滑阀磨损对伺服阀工作性能...     

微非对称结构燃油伺服阀压漂特性

偏导射流伺服阀前置级结构形式对压力漂移有极大影响。根据前置级结构参数的计算公式及伯努利方程,建立简化后前置级数学模型。以某款燃油电液伺服阀为研究对象,着重分析劈尖、接受口内侧边、接受口外侧边及V形槽等结构非对称性的影响。采用数值模拟的方式对不同回油压力及不同结构非对称条件下的前置级流场特性和压力漂移进行了仿真研究。通过PIV技术进行了流场可视化实验,验证了数学模型及仿真结果,得到了该款电液伺服阀零漂最大的工况及大小,并对改善偏导射流伺服阀的零漂提供了一定的参考依据。     

基于Fluent的偏转板射流伺服阀的前置级仿真

偏转板射流伺服阀作为伺服阀中比较常见的一种,已经广泛应用于包括军用和民用在内的各类舵机和操作系统上。在分析偏转板射流伺服阀结构及其工作原理的基础上,运用Pro/E三维软件建立了简化的前置级三维立体模型,结合ICEM前处理网格划分软件与Fluent流体仿真软件,共同构建了偏转板射流伺服阀的前置级流场分析模型。通过流场压力云图和速度云图,对偏转板射流伺服阀的前置级射流理论进行了分析;分析了不同喷嘴宽度、偏转板导流槽角度以及劈尖宽度随偏转板位移变化时对两接收孔恢复压力和压差的影响,为伺服阀的结构和参数优化提供了一定的参考依据。     

其他工程机械

正GJ20196042 V形槽位置对偏导射流式伺服阀前置级液流特性的影响[刊,中]/董娜娜…//液压与气动.-2019,(7).-1～6偏导射流级作为伺服阀关键部件,其偏转板上V形槽位置对前置级压力特性起决定性作用,进而影响了整个系统的稳定性。以某航空发动机用燃油电液伺服阀为研究对象,在分析其前置级结构及工作原理的基础上,建立偏导射流级三维模型,以Fluent流场仿真软件为平台,建立V形槽不同位置时的流场仿真模型,     

V形槽位置对偏导射流式伺服阀前置级液流特性的影响

偏导射流级作为伺服阀关键部件，其偏转板上V形槽位置对前置级压力特性起决定性作用，进而影响了整个系统的稳定性。以某航空发动机用燃油电液伺服阀为研究对象，在分析其前置级结构及工作原理的基础上，建立偏导射流级三维模型，以Fluent流场仿真软件为平台，建立V形槽不同位置时的流场仿真模型，得到了V形槽不同横向位移及纵向偏移下左右接收孔恢复压力及压差，分析了V形槽不同偏移量对前置级压力增益及液流特性的影响，为偏导射流式伺服阀装配及调试提供了一定的参考依据。     

《高端液压元件理论与实践》

<正>(ISBN:9787547834022)出版时间:2017年4月定价:148元本书系统地论述高端液压元件的理论与实践,主要内容有:高端液压元件的由来及其演变过程,新型工作介质,射流管伺服阀特性与冲蚀磨损数值模拟方法,射流管压力伺服阀,偏转板伺服阀模型与流场特性,直接驱动式电液伺服阀,飞行器单级溢流阀与极端小尺寸双级溢流阀,     

射流管伺服阀接收口形状对阀特性的影响

射流管伺服阀的接收口形状对阀的动态特性和静态特性有着直接的影响。在喷嘴形状为矩形的情况下,通过对以圆形、矩形、三角形为接收口的射流管伺服阀前置放大器进行流场数值仿真和动态特性的仿真,获得了不同形状接收口的射流管伺服阀的压力特性、流量特性和响应频宽。通过比较,发现矩形接收口的射流管伺服阀具有较高的恢复压力和较大的压力增益,当射流管喷嘴位移较小时,矩形接收口的射流管伺服阀具有线性度较好的压力特性和流量特性,频宽响应较大。     

新型压电叠堆式射流管伺服阀前置级设计及性能分析

针对当前航空工业对高频响、高精度的伺服阀需求,设计1款压电叠堆式射流管伺服阀并对压电驱动器的特性进行分析;将其与传统的电磁式射流管伺服阀的前置级进行对比,得出将压电叠堆作为前置级的伺服阀具有响应快、频响高、输出力大的优点,但存在输出位移小的缺点;针对其不足,将桥式放大机构应用到压电驱动器上,增大输出位移,提高控制精度,最终得到的压电驱动器满足射流管伺服阀的前置级使用要求。     

高压力增益偏转板射流伺服阀正交仿真试验研究

为提升偏转板射流伺服阀前置级的压力增益,采用正交试验设计与流场仿真相结合的方法,开展优化射流结构参数研究,综合考虑射流盘厚度、射流槽宽度、喷嘴宽度以及接收孔圆角半径4个结构参数对前置级压力特性的影响。结果表明,通过正交仿真试验得到的一组优化参数,相较于初始参数,其前置级的中位压力提高了15.9%,压力增益提高了19.1%,实现了前置级压力增益提升的目标,为偏转板射流伺服阀射流结构参数设计提供了依据。     

偏导射流阀前置级流场特征参数的仿真计算

根据偏导射流阀前置级的结构以及内部油液的流动特性,将前置级射流过程分为两个阶段。采用标准k-e模型对前置级流场进行了两相流二维数值计算,对两次射流过程中油液的流动形态以及流场压力和速度分布特点展开研究。分析得出,初次射流为自由紊动射流,二次射流为冲击射流,并发现在偏转板处于中位时两接收腔外侧圆弧拐角低压区处出现空化现象。偏导射流阀实际工作过程中偏转板会发生偏移,因此,建立了不同偏移量下的仿真模型,分析了不同偏移量下流场信息的变化规律,获得了前置级流场的压力云图以及对应的速度矢量图。利用仿真结果中两接收腔压力值和V形槽两侧壁静态压力数据,分别计算出了前置级流场的压力增益和液动力的大小。为偏导射流阀基础特性的深入分析奠定了基础,并对该类阀设计的改进和优化具有理论指导意义。     

射流管伺服阀前置级的动态流场分析

射流管电液伺服阀的喷嘴到接收孔间的流场较为复杂,尤其在射流管偏转及阀芯运动的动态情况下,会存在回流、漩涡等现象。以某型射流管电液伺服阀结构为模型,结合射流管偏转时的阀芯力平衡关系,得到阀芯的运动方程,应用雷诺平均方程和标准两方程模式的封闭方程,通过流体动力学软件FLUENT建立射流管伺服阀喷嘴到阀芯两腔的三维可视化模型,仿真分析了喷嘴到接收孔的前置级瞬态流场及阶跃响应。仿真结果表明:接收孔中的涡量强度会影响射流管电液伺服阀的阶跃响应,涡量强度越大、振荡越大、阶跃响应越慢,并通过试验测试阀芯位移验证了数值计算的正确性,同时对比了不同接收孔间夹角的同时刻涡量及阶跃响应,得到接收孔间夹角为45°的最优设计。研究方法和结果对于提高射流管电液伺服阀的动态响应有重要参考价值。     

Particle erosion transient process visualization and influencing factors of the hydraulic servo spool valve orifice

The erosion of the valve orifice can easily lead to the performance degradation of the hydraulic servo spool valve, which seriously affects the service life and reliability of the hydraulic servo system. In this paper, the erosion micro-morphological characteristics, erosive transient process visualization of solid particles, and factors affecting the erosion rate of the spool working edges were investigated. The results showed that there was a significant “edge collapse” phenomenon on the working edges of the spool, which was mainly characterized by surface peeling, notches, grooves, chamfers, and the radius of the fillet which fluctuated violently in the circumferential direction. The “smoothing, slipping, and somersaulting” evolution process started when the incident angle increased and the particles hit the valve orifice by a new visualization experiment model composed of the nozzle-baffle submerged jet. The erosion rate of the working edges also showed continuous fluctuations and violent changes, with strong scatter-like distribution characteristics. The erosion rate of the working edge in the up-flow field was approximately one time higher than that in the back-flow field. The erosion rate of the working edges increased as the oil viscosity and particle concentration increased. Under small openings, the impact frequency of particles and the working edge increased significantly. The distribution law of the erosion rate of the working edge agreed with the distribution characteristics of the erosion fillet radius of the working edges. The erosion rate variance was defined, which can be used to quantify the circular distribution of erosion rate. This study provides further understanding of the mechanism and influencing factors of the hydraulic servo spool valve erosion.     

Analysis of the Internal Characteristics of a De ector Jet Servo Valve

In current research on deflector jet servo valves, the receiver pressure estimated using traditional two-dimensional simulation and theoretical calculation is always lower than the experimental data; therefore, credible information about the flow field in the prestage part of the valve can hardly be obtained. To investigate this issue and understand the internal characteristics of the deflector jet valve, a realistic numerical model is constructed and a three-dimensional simulation carried out that displays a complex flow pattern in the deflector jet structure. Then six phases of the flow pattern are presented, and the defects of the two-dimensional simulation are revealed. Based on the simulation results, it is found that the jet in the deflector has a longer core area and the fluid near the shunt wedge cannot resist the impact of the high-speed fluid. Therefore, two assumptions about the flow distribution are presented by which to construct a more complete theoretical model. The receiver pressure and prestage pressure gain are significantly enhanced in the calculations. Finally, special experiments on the prestage of the servo valve are performed, and the pressure performance of the numerical simulation and the theoretical calculation agree well with the experimental data. Finally, the internal mechanism described by the theoretical and numerical models is verified. From this research,more accurate numerical and theoretical models are proposed by which to figure out the internal characteristics of the deflector jet valve.     

偏导射流阀前置级流场计算与分析

根据射流盘处的结构和液流的实际运动情况,综合考虑射流过程中能量转化过程,提出了偏导射流放大器的二次射流模型,得到偏导射流阀前置级紊动射流的速度分布和时均动能变化,进一步研究了阀芯在中位条件下接收口的压力特性。结果表明了该模型具有合理性,为偏导射流阀的进一步研究提供了理论依据。