Development of a novel rotary flow control valve with an electronic actuator and a pressure compensator valve for a gas turbine engine fuel control system

This paper presents a new rotary proportional flow control valve with Cam-Nozzle configuration. The rotating cam against the fixed nozzle changes the flow area and then can meter the fuel flow. This valve equipped with a pressure compensator plunger type valve to retaining constant pressure difference across the flow control or metering valve. The cam shaft directly coupled to an electronic servomotor type rotary actuator and then it is possible to apply digital control techniques such as pulse width modulation (PWM) in this control system. This new valve configuration is developed for an electro hydro mechanical fuel control system in a gas turbine engine. In addition to aero engine application, this type of flow metering valve can widely be used in industrial hydraulic systems. In this unit, the output flow is proportional to the cam's angular position (or throttle command) and it is not sensitive to pressure fluctuations at nozzle inlet and outlet. The aim of this new design is to modify a manual single adjusted hydro-pneumatic fuel control unit to obtain a new electro-hydraulic fuel control system for a gas turbine engine. The main innovations in the presented fuel metering unit include new design of the rotary valve opening shape (Cam-Nozzle) without metal to metal contact, use of a rotary electronic actuating mechanism and also direct coupling between the actuator and the rotating cam. The increased fuel metering precision in the new flow control valve has improved the ultimate control accuracy of system. A computer simulation software based on the proposed model, is performed to predict the steady state and transient performance and to analyze effect of important design parameters on valve outlet fuel flow and obtain the final design parameters. The validity of the proposed valve configuration is assessed experimentally in the steady state and transient modes of operation. The results show good agreement between simulation and experimental in both modes (max. 4% deviation).     

Flow analysis of a switching valve with innovative poppet head geometry by means of CFD method

The article presents an analysis of flow through a differential switching valve installed inside a throttle-check valve block. The valve is mounted in a sandwich type arrangement together with a control valve according to ISO 4401 standard. This type of block arrangement is popular and commonly used in hydraulic drive systems. The development of a typical throttle-check valve using a differential switching valve makes it possible to add a secondary fluid stream and thus increase the inflow rate to an actuator, which is particularly important in fixed-delivery pump systems. Due to the limited range of valve dimensions and the need to adapt flow paths to connection ports, channels of complex geometry are made inside the valve block. Therefore, the main aim of the work was to properly profile geometry of the differential switching valve spool in order to obtain a smooth opening in the entire displacement range. A 3D model of flow paths was built and CFD analysis was carried out. The obtained results of numerical simulations have been confirmed experimentally on a test bench. The CFD analysis allowed values of velocity and pressure profiles as well as axial flow force acting on the spool to be determined. The proposed new shapes of the spool head geometry significantly increase the spool head operating range. Although flow rate in the initial phase of switching valve opening was reduced, the amplitude of fluid flow fluctuations also decreased.     

膜片式先导水压溢流阀仿真与试验研究

由于水的粘度低和润滑性差,先导型水压溢流阀中主阀芯与阀套之间的密封与润滑问题一直是影响阀静动态性能的关键性技术难题。设计出一种采用膜片密封的新型先导型水压溢流阀,较好地解决了先导型水压溢流阀的密封与润滑难题。建立该阀的数学模型,对其静态特性进行理论分析和计算,对其动态特性进行仿真,分析主阀下腔容积、阻尼孔直径、先导阀弹簧刚度、主阀上腔容积以及阀芯质量对阀压力响应和压力超调量等动态性能的影响。制作样机并对其调压范围、启闭性能和动态性能进行试验研究。试验结果表明,样机的压力调节范围较大、启闭特性非常好、压力超调量较小以及升压时间较短,验证了该阀能较好地解决主阀芯与阀套之间的密封与润滑难题。     

液压支架用高压大流量液压元件综合性能试验台的设计

介绍了一种以乳化液为介质的煤矿液压支架用高压大流量液压元件综合性能试验台的系统原理。设计了一种带尾部减振槽的插装阀和一种带缓冲阀的卸荷溢流阀,仿真优化结果表明,减振槽和缓冲阀的设置可大大减小压力梯度的极值,有利于减小振动和噪声;利用VB设计了综合性能试验台的测控系统。通过调试和实验证明,所研制的试验台及其测控系统能够满足液压支架用阀的试验要求。该试验台将在煤矿安全生产中发挥重要作用。     

Valvistor电液比例流量阀稳定性及特性分析

插装式比例阀具有低泄漏、通流能力强、结构简单等优点,广泛应用于液压系统中,但插装阀所带来的振动及噪声等问题是制约其使用范围的重要因素。对采用流量放大原理的Valvistor型插装阀稳定性及性能进行研究,建立相应的数学模型得出该阀的稳定性条件,发现主阀稳定性与先导阀开口及面积增益有关;在SmiluationX软件环境中建立该阀的仿真模型,并利用实验对其进行验证。理论分析与仿真结果表明:随着主阀进出口压差、反馈窄槽面积梯度的增大,主阀芯响应速度加快,但会导致主阀芯不稳定区域增加;控制腔体积越小,主阀芯稳定性越好。研究结果为该类型阀性能的提高提供了理论依据。     

负载口独立控制双联阀建模与特性分析

 为解除液压执行元件进出口之间的联动,提出了一种负载口独立控制双联阀,基于2个单元体阀芯错位组合,能实现负载口的独立控制。根据其工作原理,建立了阀控缸数学模型,进一步利用MATLAB/Simulink搭建了数值求解模型,对该阀在3种不同工况下的工作特性进行了分析。分析结果表明,通过对阀芯角位移和线性位移在工作行程零位及行程末端附近的联合控制,分别可实现微小流量稳定控制和大流量快速响应控制;阀芯角位移单独控制时,负载流量与之成正比,具有良好的线性流量增益效果;阀芯线性位移单独控制时,相同供油压力下能获得最大的负载流量和活塞位移。该阀具有较高的流量控制精度和灵活性,可为复杂工况下流量和压力的匹配补偿控制提供新思路。     

溢流式高速缓冲气缸动力学建模与性能分析

针对具有内置溢流阀的溢流式高速缓冲气缸建立了非线性动力学模型,并运用Simulink软件建立仿真模型进行数值计算,得到气缸在缩回运动过程中的位移、速度以及各腔室压力的仿真数值解。为了验证仿真模型的正确性,搭建了高速气缸缓冲性能测试平台,对气缸在运动过程中的相关动态参数进行试验测试,通过试验数据与仿真结果的对比分析来对仿真模型进行验证。最后通过仿真分析了内置溢流阀的阀芯质量和预紧弹簧刚度对气缸缓冲性能的影响,结果表明,不同的溢流阀阀芯质量和预紧弹簧刚度都对气缸缓冲性能有较大的影响,为进一步研制更高性能的高速气缸缓冲结构提供了重要依据。     

配合间隙对溢流阀稳态液动力的影响

针对稳态液动力影响电液比例溢流阀调压精度的问题,建立了内流式滑阀液动力数学模型,基于CFD仿真平台,构建了考虑配合间隙的滑阀模型,并搭建了试验平台以验证模型的正确性,研究了不同配合间隙对滑阀稳态液动力的影响。结果表明：考虑配合间隙的滑阀模型与试验测试结果有很好的一致性;溢流阀在工作过程中,阀口开度与配合间隙非常接近,随着压力升高,阀口开度变小,射流角接近20°;随着配合间隙增大,阀口开度变小,射流角变大;配合间隙在一定范围内,液动力随着间隙增大而增大,当达到临界值后,配合间隙对液动力的影响变小。     

静液驱动插装式安全阀压力特性分析及试验研究

以一种静液驱动插装式高压安全阀为研究对象，根据静液驱动系统及安全阀的工作原理，运用AMESim仿真软件建立静液驱动插装式高压安全阀仿真模型。通过对高压安全阀阻尼孔、弹簧预紧力、阀芯锥角结构进行参数设置并批量仿真，对比分析得到了不同结构参数对高压安全阀压力特性的影响。设计了试验回路，通过搭建压力性能试验平台，测量得到试验曲线，与仿真结果进行对比，验证了仿真结果的准确性。为插装式高压安全阀的结构优化和选型提供指导性建议。     

Development of a novel two-dimensional(2D) three-way(3W) fuel flow control servo valve with constant pressure difference

To solve the problems of large volume, and low integration of traditional electro-hydraulic servo valve with constant pressure differential fuel metering device, a new two-dimensional three-way constant pressure differential fuel flow control servo valve (2D3WFFCSV) is developed. It innovatively adopts the advantages of lightweight of “two-dimensional hydraulic technology”, The constant differential pressure function and flow regulation function are integrated into a two-dimensional (2D) main spool with two degrees of freedom (rotational and axial degrees of freedom). The flow control process of 2D3WFFCSV is as follows: firstly, the armature of the torque motor and the two-dimensional piston are coaxially installed at the end of the two-dimensional piston, so the torque motor can directly drive the two-dimensional piston to rotate; secondly the “hydraulic servo screw mechanism”, which can amplify the power, is used to drive the two-dimensional piston to move in line; Finally, a pair of conversion mechanisms (roller group and spiral track conversion mechanism) are converted into the angular displacement of 2D main spool to control the area of flow valve port. The axial degree of freedom of 2D main spool realizes the function of constant differential pressure. To improve the flow control accuracy of the servo valve, the axial position of the 2D piston is detected by the linear displacement sensor (LVDT), and the signal is transmitted to the controller to realize the closed-loop control. To explore its open-loop characteristics, the mathematical models of torque motor, two-dimensional piston and main spool are established to obtain its open-loop transfer function. Then the AMESIM simulation model is built. To optimize the design of the system, through the dynamic simulation of the system, the influence of key parameters on the dynamic response of the system can be studied. An experimental study is carried out to verify the design feasibility of the servo valve. The experimental results show that under the condition of no-load and full-scale input, the closed-loop delay of the servo valve is 1.84%, the linearity is 2.14%, the step response time is 43 ms, and the dynamic frequency response is 38 Hz. The newly developed 2D3WFFCSV has the advantages of high integration, small size, light weight (801.5 g) and high response and control accuracy. It can replace the constant differential pressure, metering valve and hydraulic servo valve in the aeroengine fuel regulator.     

双U形节流槽滑阀多场耦合特性研究

压滑阀在工作过程中阀芯卡滞及磨损现象严重,为了改善阀腔流域特性及液压阀的工作性能,构建了液压滑阀的简化模型,基于计算流体力学对双U形节流槽滑阀阀芯及阀腔内流域动态特性进行了分析。研究了节流槽数量、阀口压差对阀腔内流体速度场、阀芯温度场及阀芯应变场动态特性的影响。研究结果表明,随着阀口压差的增加,流体的最大流速以及阀芯的最高温度和最大变形增大;随节流槽数量的增加,阀芯的最大变形增大,流体流速及阀芯最大温度变化微弱。该研究为阀芯优化设计提供了参考。     

2D数字伺服阀的简介

该文主要阐述了2D数字伺服阀的结构原理及工作原理,建立了电—机械转换器的数学模型,设计了2D数字伺服阀控制器。为了获得电—机械转换器及样阀的性能,对其进行了实验研究,实验结果表明,该电—机械转换器具有良好的频率特性,对应-3dB、-90°的频宽约为250Hz;2D数字伺服阀具有良好的静态、动态性能,其分辨率与滞环皆在1%以内,阀在25%满量程正弦输入信号下,对应-3dB、-90°的频宽约为130Hz。     

某型导弹发射筒安全阀设计及动态特性仿真分析

安全阀是导弹发射筒装置上的一个重要元件,用于导弹发射后发射筒的安全卸压,从而对导弹发射筒及空气压缩机起到保护作用。针对某型导弹发射筒超压泄放的特定需求,设计出一种新型发射筒安全阀,并在此基础上建立其AMESim仿真模型,对其动态特性进行仿真分析,得到安全阀流道直径、容积腔体积、阀芯质量和弹簧刚度对该安全阀入口压力、流量、阀芯速度及阀芯振幅的影响规律。结果表明:在满足压力和流量要求的前提下,流道直径、容积腔体积和阀芯质量越小,弹簧刚度越大,阀芯振幅和速度波动越小,安全阀动态稳定性越好。     

Investigation on the dynamic characteristics and control accuracy of a novel proportional directional valve with independently controlled pilot stage

The pilot operated directional valves are widely used in hydraulic systems. For the purpose to improve the dynamic characteristics and control accuracy of the traditional valve, this paper proposes a novel pilot valve that employs two independent valve spools instead of the traditional port coupled valve spool. Due to the new structure, the influence of deadzone and damping on the performance of the valve is lightened; the dynamic characteristics and control accuracy of the valve are improved. Both of the open-loop simulation and experimental closed-loop position control of the entire valve demonstrate that the novel valve has impressive performance improvement of the entire valve. The results of experiments show that the -3dB-frequency of novel valve improves 61.5% in the case of single side control mode (SS) and 57.1% in the case of both side control mode (BS); the tracking error decreases from 6.21% to 2.6% in the case of SS and from 7.48% to 3.96% in case of BS.     

基于FLUENT的滑阀液动力补偿的研究

液动力是滑阀和阀腔的结构设计中考虑的关键因素之一。提出了一种在阀套上开圆弧型进出口流道的方法,对进出口处的油液进行导流,以达到减小液动力的目的。同时利用FLUENT软件分析该阀内流场,并与传统的直流道滑阀相比较,然后对改进后滑阀的液动力特性和阀口流量特性分析计算。该研究对滑阀的结构优化设计有一定的参考意义。     

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...     

Geometric optimization and performance analysis of radial MR valve using Taguchi orthogonal experiment method

Aiming at the problems of increasing external dimensions and deteriorating key performance indicators in the design process of magnetorheological (MR) valve by using structural optimization method, a geometric optimization design methodology for the optimal design of a MR valve structure under specific volume constraints is proposed in this article. The optimization methodology couples the finite element model (FEM) constructed in COMSOL software with the Taguchi orthogonal experiment and response surface technology to build an approximate response surface function for the identified independent variables. Suitable optimization algorithms are then utilized to determine the optimal geometry of the MR valve, thereby maximizing the valve performance. Firstly, a radial MR valve with a single excitation coil was presented, and its structure and working principle were also elaborated. A mathematical model of the pressure drop was derived on the basis of the Bingham-Papanastasiou non-Newtonian constitutive model of MR fluid and the magnetic circuit had been analyzed with the FE analysis methodology. Then, a second-order response surface model (RSM) had been fitted for the magnetic flux density in the radial flow channel and spool region of the radial MR valve based on the Taguchi orthogonal experimental design. The fitted model was a function of the four independent variables of the radial MR valve, and the accuracy of the developed response surface function over the entire design space had also been estimated. Meanwhile, predictions made by the RSM and FE models were evaluated by analysis of variance and it was exhibited that the RSM model’s results agree with FE result fairly. Subsequently, the geometric optimization problem had been formulated for the constructed RSM exploiting the genetic algorithm to find the global optimum geometrical parameters of the radial MR valve. Furthermore, the experimental test rig was setup to explore the pressure drop and the response time characteristics of the initial and optimal radial MR valve as well as the dynamic performance of the MR valve controlled cylinder system under different excitation conditions. The experimental results show that under the applied current of 2 A, the pressure drop and adjustable coefficient of the optimal radial MR valve observably increased with values of 3.15 MPa and 5.40, respectively, when compared to 2.11 MPa and 4.22 of their respective initial values. Also, at the applied current of 1.25 A, the damping force of the MR valve controlled cylinder system enlarged by 46 %, with its optimal value being 3.65 kN and initial value as 2.50 kN, which was an excellent verification of the correctness of the RSM and the effectiveness of the optimal design.

     

基于双线性插值控制策略的比例流量阀特性研究

当前液压调速阀通常采用机械式压差补偿器或动态流量器等方式实现输出流量的精确控制,但存在机械结构复杂、通流量小,以及输出流量受负载影响大等不足。提出一种基于双线性插值的流量补偿策略,并将该策略应用到以Valvistor阀为主阀的比例流量阀中,形成具有数字流量补偿功能的比例流量阀,其包括主阀、先导阀、压力传感器和流量补偿器,压力传感器的作用是检测反馈主阀进、出口压力;流量补偿器以主阀进、出口压力和设定流量为输入变量,经双线性插值计算后,流量补偿器输出流量校正控制信号,调节先导阀开口以补偿主阀口压差变化对输出流量的影响,从而实现流量的精确控制。建立该比例流量阀的简化数学模型（不考虑流量补偿器）,研究发现输出流量、先导阀输入电压与主阀压差平方根之间存在着线性关系,基于此特征,设计基于双线性插值算法的流量补偿器,并利用仿真和试验对该流量阀的动、静态特性进行研究;结果表明该流量阀输出流量具有良好的静态控制精度且受主阀压差变化的影响较小;若主阀口压差越大,则主阀芯动态响应会越快;对于由负载压力阶跃变化产生的主阀压差而言,若主阀压差越大,则系统流量抗干扰能力随之减弱。     

Parameter tuning method for dither compensation of a pneumatic proportional valve with friction

In the practical application of pneumatic control devices, the nonlinearity of a pneumatic control valve become the main factor affecting the control effect, which comes mainly from the dynamic friction force. The dynamic friction inside the valve may cause hysteresis and a dead zone. In this paper, a dither compensation mechanism is proposed to reduce negative effects on the basis of analyzing the mechanism of friction force. The specific dither signal (using a sinusoidal signal) was superimposed on the control signal of the valve. Based on the relationship between the parameters of the dither signal and the inherent characteristics of the proportional servo valve, a parameter tuning method was proposed, which uses a displacement sensor to measure the maximum static friction inside the valve. According to the experimental results, the proper amplitude ranges are determined for different pressures. In order to get the optimal parameters of the dither signal, some dither compensation experiments have been carried out on different signal amplitude and gas pressure conditions. Optimal parameters are determined under two kinds of pressure conditions. Using tuning parameters the valve spool displacement experiment has been taken. From the experiment results, hysteresis of the proportional servo valve is significantly reduced. And through simulation and experiments, the cut-off frequency of the proportional valve has also been widened. Therefore after adding the dither signal, the static and dynamic characteristics of the proportional valve are both improved to a certain degree. This research proposes a parameter tuning method of dither signal, and the validity of the method is verified experimentally.     

6通径旋转型换向阀的设计分析

根据换向阀6通径、三位四通的设计要求完成设计。通过改变阀芯相对阀体的位置使阀芯做旋转运动,实现油液的沟通、切断及换向,满足工作要求的控制。进行应力分析及换向阀阀腔压力损失分析,完成了旋转型换向阀阀芯的结构设计。在满足结构强度和0.5 MPa压力损失的条件下完成了阀体和顶板的结构设计,使用CFD软件对旋转阀进行了流量特性仿真。将旋转阀加工成实体进行试验,试验结果与CFD仿真的流量特性进行对比,结果较吻合。