节流槽型阀口噪声特性试验研究

运用压力分布测量、噪声测试、流场仿真及理论分析对典型节流槽的噪声特性进行了研究。压力分布测量结果与流场仿真吻合良好,在大量试验的基础上揭示了节流槽的噪声特性规律。研究发现节流槽型阀口噪声与流场压力分布特征密切关联,噪声主要取决于节流槽形状、流动方向及背压大小,渐扩形节流槽容易出现啸叫,而具有等截面流道的节流槽噪声较低。此项研究对于具有节流槽液压元件的噪声控制具有重要的理论价值和工程实用价值。     

内流道形状对溢流阀气穴噪声影响的研究

从流场控制的角度,研究了溢流阀内流道结构对气穴及气穴噪声的影响。采用流场数值仿真和流动显示试验,获得了溢流阀主阀流道内的压力和气穴分布图像,仿真结果中的低压区与试验结果中气穴区基本吻合。此外,对两种溢流阀主阀流道结构进行了噪声测试和对比分析。结果表明,具有环形槽的主阀芯结构能有效抑制气穴和气穴噪声。这项研究对于以降低噪声为目标的溢流阀流道结构优化设计具有一定的指导意义。     

基于压力分布模式的液压阀空化噪声评价

比较Oshima和Ichikawa由液压锥阀实验所得空化噪声变化和阀座上的压力分布曲线,提出基于压力分布模式评价液压锥阀空化噪声的方法。对实验所用液压锥阀进行CFD解析,得到阀座上的压力分布曲线,与实验所得噪声曲线相比较,找到评价节流口噪声的3种压力分布模式。对带V形节流口的液压滑阀流入和流出两种流动状态进行CFD解析,验证了压力分布模式评价方法在滑阀空化噪声评价中的可行性。     

Study on the design of control valve for U-shaped noise reduction cage and its fluid flow features and noise

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.     

倒角阀座式水压锥阀空化射流动态行为数值模拟

使用可压缩的VOF空化两相流算法对倒角型阀座水压锥阀的空化射流进行了三维瞬态流场仿真。模拟结果揭示,空化结构首先在狭窄的倒角阀座流道内以附着空化的形式出现;在压差为4.4 MPa的工况条件下,空化分布集中在3个区域,阀座流道内及阀芯后沿的附着型空化,阀座流道至阀芯后沿的漩涡空化。射流势核在阀座流道入口及阀芯后沿均有分离流现象,从而诱发附着型空化;而大尺寸漩涡结构主要分布于射流势核的自由剪切层侧,漩涡空化亦相应地集中在自由剪切层侧,壁面侧偶发性形成薄层型漩涡空化。由于整体的空化行为涉及多个不同类型空化的耦合,其动态演变的周期特性受到干扰。阀座流道后部的脱落空化伴有明显的三维漩涡结构,阀芯后沿的漩涡空化与附着空化通过耦合作用形成大尺寸汽泡结构,揭示了后沿下游稀疏分布的大尺寸空化结构的产生过程。通过开展三维瞬态模拟,结合流场结构探索了空化射流的动态特性,从流体力学的层面解释了实验观测到的空化形态及分布规律。     

基于全空化模型的高压柱塞泵配流盘空化研究

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。     

Noise Reduction of an Axial Piston Pump by Valve Plate Optimization

Current researches mainly focus on the investigations of the valve plate utilizing pressure relief grooves. However,air?release and cavitation can occur near the grooves. The valve plate utilizing damping holes show excellent perfor?mance in avoiding air?release and cavitation. This study aims to reduce the noise emitted from an axial piston pump using a novel valve plate utilizing damping holes. A dynamic pump model is developed,in which the fluid properties are carefully modeled to capture the phenomena of air release and cavitation. The causes of di erent noise sources are investigated using the model. A comprehensive parametric analysis is conducted to enhance the understanding of the e ects of the valve plate parameters on the noise sources. A multi?objective genetic algorithm optimization method is proposed to optimize the parameters of valve plate. The amplitudes of the swash plate moment and flow rates in the inlet and outlet ports are defined as the objective functions. The pressure overshoot and undershoot in the piston chamber are limited by properly constraining the highest and lowest pressure values. A comparison of the various noise sources between the original and optimized designs over a wide range of pressure levels shows that the noise sources are reduced at high pressures. The results of the sound pressure level measurements show that the optimized valve plate reduces the noise level by 1.6 d B(A) at the rated working condition. The proposed method is e ective in reducing the noise of axial piston pumps and contributes to the development of quieter axial piston machines.     

节流槽形式对滑阀空化流场的影响

为了提高采煤工作面液压支架推移拉架准确度,降低空化现象对控制滑阀性能的影响,采用Pumplinx建立了不同节流槽形式下滑阀内部流体域动态模型。仿真分析了不同节流槽形式滑阀在不同开度时,压力场和空化分布以及气体体积分数的变化趋势。结果表明:不同节流槽形式对滑阀内部的压力分布和空化分布具有不同的影响;气体体积分数随着阀口开度的增大,呈现先稳定波动然后陡增最后在阀口完全开放后迅速降低的现象;交错分布形节流槽空化剧烈起始位置为4.5 mm,最大气体体积分数约为0.12,相较于其他槽形明显降低。     

2D伺服阀矩形先导控制阀口气穴特性研究

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。     

孔隙高速流动中的气穴观测与噪声特性

为研究阀口高速流动中的旋涡空化机理及其与噪声特性的关系,运用高速摄像、噪声频谱分析等手段对典型阀口孔隙节流处的流场及流动现象进行分析.利用高速摄像机在微距模式下对阀口流场进行观测,最高拍摄速度达120 000幅/s.研究发现空化的产生与流动分离受背压的影响最为明显,进口压力对气穴形态及噪声影响次之;孔口较深时,不同流动参数下气穴初生的位置始终位于节流边与孔壁相交的锐缘区附近,随着阀口开度的变化,初生位置稍有变化.频谱分析同时表明,气穴的形态和尺度是影响噪声的最重要因素之一.     

配流盘三角形节流槽抗空化结构改进研究

轴向柱塞泵配流盘三角形节流槽主要是减小柱塞腔及泵出口压力的波动。由于节流槽过流面积小,且槽两端压差大,流体高速流过节流槽的同时压力急剧减小,从而产生空化。为减小配流盘三角形节流槽的空化,提出对配流盘三角形节流槽抗空化的结构改进方案:预卸压阶段,在不改变节流槽通流面积的条件下,减小三角形节流槽倾角可提高其空化抑制性;预升压阶段,在保证三角形节流槽进口过流面积不变时,增大出口的过流面积可有效抑制三角形节流槽的空化。通过仿真分析发现三角形节流槽结构改进后轴向柱塞泵的抗空化性能提高,泵空化程度降低。     

水压锥阀空化射流流场结构与流量特性的相关性研究

为了研究水压锥阀空化流场与流量特性的相关性,对两种阀座结构的水压锥阀内部的空化射流开展了三维动态流场仿真.结果表明,直角型锥阀和倒角型锥阀均在阀芯后沿存在分离流诱发的附着型空化,在阀口下游有漩涡空化;此外,倒角阀座流道内亦存在分离流现象并形成附着型空化.倒角型流道入口处的分离流造成流体的局部加速,对于0.6 mm开口度...     

直角截止阀噪声特性分析及优化设计

针对直角截止阀振动噪声较大的实际问题,建立了某型号直角截止阀的流场结构,并利用CFD数值计算方法对其在不同开度下的压力、速度和湍流动能进行了计算。计算结果显示,直角截止阀在阀口位置具有明显的空化现象和湍流噪声,且阀口开度越小,噪声问题越明显。针对该问题,对直角截止阀的阀芯、阀座和回油腔流道结构进行了低噪声优化设计和计算分析。计算结果表明,优化后的新型直角截止阀与原阀相比,空化系数减小了10%以上、湍流噪声降低了20 dB以上,具有良好的低噪声性能。     

基于Fluent的挖掘机多路阀动臂联流场分析

针对多路阀在使用过程中的发热、异响、压力损失过大等问题，应用数值模拟的方法对液压挖掘机多路阀动臂联进行流场分析。基于流体动力学理论，利用Fluent软件得到了动臂2联阀芯在开启过程中，节流槽前、后的流速、压力及其差值的变化情况。通过数据分析，得到了多路阀动臂联稳态流场的内部流动规律和稳态液动力变化规律。观察发现动臂2联阀口开度在2.1～4 mm时，压差与速差同时发生突降现象，并且液动力的变化较大，容易产生振动、噪音和气穴等现象。研究结果表明，通过对多路阀阀芯开启过程的流场分析，所获得的流速、压力和液动力等数据可以作为多路阀优化设计的参考依据，从而提升多路阀的工作效率和使用寿命。     

喷嘴挡板伺服阀前置级流固耦合特性研究

伺服阀前置级流固耦合特性与伺服阀的稳定性、快速性、气穴和自激噪声的产生密切相关。为研究喷嘴挡板伺服阀前置级流场的瞬态气穴分布特性以及流场作用下挡板的位移特性,提出了伺服阀前置级流固耦合分析方法,采用STAR-CCM+软件对伺服阀前置级流固耦合特性进行仿真分析,并通过流场分布规律实验观测对仿真方法进行了验证。结果表明,伺服阀前置级的流固耦合作用会引起流场周期性的瞬态分布和挡板谐振。     

基于PumpLinx纯水轴向柱塞泵配流盘卸荷槽结构的仿真分析

以纯水轴向柱塞泵为研究对象,在同时考虑配流盘间隙和柱塞间隙的基础上,利用流体仿真分析软件PumpLinx,采用动网格技术并建立空化模型,研究配流盘减振结构对流量特性和压力脉动的影响。通过仿真分析U型槽、三角槽、孔槽结合和无阻尼槽四种不同的减振方案在配流过程中的压力脉动和流量脉动,进而比较得出最佳的高压卸荷槽结构。仿真结果表明,采用U型槽结构的配流盘在预升压过程中优于其他三种结构,且其出口的流量更加平稳,脉动率更小。     

Cavitation effect on flow resistance of sleeve regulating valve

Sleeve regulating valve is the key component of the industrial system. As the main cause of vibration and noise inside the sleeve regulating valve, cavitation also increases the energy loss when fluid flows through the valve. In this paper, in order to quantitatively analyze the influence of cavitation in the sleeve regulating valve, the effects of throttling windows number, pressure difference, valve opening and flow direction on the resistance coefficient are investigated with the application of cavitation model. By defining the cavitation influencing factor of the resistance coefficient, the calculation formula of the resistance coefficient when cavitation occurs in the sleeve regulating valve is proposed. The results show that when the fluid flows forward and the aggravation degree of cavitation increases, the energy loss also increases. And in the backward flow, the effect of cavitation on the resistance coefficient is related to the valve opening and the throttling windows number. This work is of significance for the optimization and design of sleeve regulating valve and pipeline system.     

配流盘对轴向柱塞泵声振特性的影响

通过振动和噪声测试试验台,在两种不同的试验工况下,分别对轴向柱塞泵的表面振动速度和声压级进行了测试。使用傅里叶变换对测试数据进行处理,分析了不同试验工况下轴向柱塞泵的声振特性,探讨了振动速度和声压级之间的对应关系。然后对比了两种配流盘结构对声振特性的影响,给出了阻尼孔以及三角槽结构的配流盘的适用范围和各自的优势,为不同工况下轴向柱塞泵配流盘结构的选择提供了一定的参考。     

高频电液数字转阀阀口气穴现象研究

借助FLUENT软件对高频电液数字转阀(简称2D数字阀)阀腔流场进行研究,主要对阀口极端环境时的气穴变化规律进行深入探索,揭示2D数字阀阀芯高速旋转时阀口气泡析出、发育过程及溃灭特性对阀口流量的影响。研究结果表明,气穴现象不仅会造成流量阻塞,而且气泡溃灭引起的压力脉动还会对系统形成强非线性干扰,影响阀口输出波形的精度和阀控液压缸激振系统的稳定性。     

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.