柱塞倾角对航空柱塞泵性能的影响分析

通过对柱塞泵中柱塞的运动方程和柱塞泵的瞬时供油量方程进行分析,利用AMEsim工程仿真软件,建立了某型航空发动机柱塞泵的仿真模型,通过仿真分析了柱塞倾角对柱塞行程、柱塞泵的流量脉动和压力脉动的影响,仿真结果表明柱塞倾角是影响泵流量脉动的重要因素,适当增大柱塞倾角,可以增大柱塞的行程,增加泵的供油量,还能够改善柱塞泵流量的脉动。     

一种液压系统脉动消除器的设计与分析

面向航空液压系统消除压力脉动、提升系统可靠性和寿命的需求，设计了一种液压系统压力脉动消除器。基于流体网络理论建立了脉动消除器及实验系统的理论模型，并考虑安装方式和负载类型的不同，分析了脉动消除器在不同工况下的滤波效果。然后通过仿真方法验证了设计方案的可行性以及理论分析的准确性，仿真过程考虑了系统负载对脉动的影响。最后实验验证了脉动消除器的滤波效果。结果表明：设计的新型结构压力脉动消除器无运动部件、布局紧凑，与飞机液压系统中常用的液压柱塞泵使用匹配度高，是消除液压系统脉动的有效部件；在300~500 Hz的压力脉动频率范围内，研究设计的脉动消除器可以消除10 dB的压力脉动，能够满足飞机液压系统消除压力脉动的需求，在航空领域中具有广泛的应用前景。     

轴向柱塞泵多学科融合建模与集成优化

为了实现机液耦合条件下轴向柱塞泵的精确建模和优化设计,提出了轴向柱塞泵多学科融合建模与集成优化方法。以国产I3V2-10S型轴向柱塞泵为对象,分别建立了ADAMS机械系统模型和AMESIM液压系统模型,通过ADAMS和AMESIM之间的接口模块设计实现了柱塞泵机液耦合建模和联合仿真,并利用iSIGHT软件集成了该机液耦合模型,以该柱塞泵出口体积流量脉动率最小为目标,对配流副中吸排油节流口最大开口等效直径、吸排油闭死角、柱塞包角、吸排油预开口量等参数进行了优化设计。结果表明:在负载工况分别为10、14、18、22、26、30MPa时,优化后的泵出口流量脉动率比优化前分别降低了14.59%、18.57%、21.50%、23.44%、24.03%、25.49%,最后通过实验验证了仿真和集成优化数据的正确性。      

某型飞机轴向柱塞泵性能分析

通过对轴向柱塞泵的基本性能分析,推导出了流量、脉动系数、流量脉动频率计算公式。通过对某型飞机柱塞泵的流量、脉动系数、流量脉动频率计算,定量得出柱塞泵的脉动系数值和流量、流量脉动频率变化范围,从而对轴向柱塞泵的基本性能作出理论上的量化分析。     

高压柱塞泵压力脉动分析及抑制措施

高压柱塞泵压力脉动影响液压系统工作性能。本文在分析高压柱塞泵压力脉动机理与现象的基础上,介绍了抑制压力脉动的四种措施,即壳体内设置缓冲瓶、配油盘带有节流孔、柱塞采用封闭薄壁结构、在泵的变量机构处增加一个补偿器。实践表明,这些抑制措施是有效可行的。     

二维燃油泵的设计与研究

提出一种新型的二维燃油泵，说明了其诸多优点。为研究其结构性流量脉动，利用仿真软件AMESIM建立了二维燃油泵的仿真模型进行理论研究，并进行了实验验证。通过齿轮泵与轴向柱塞泵的对比，说明了轴向柱塞泵在燃油系统应用中的优势。针对轴向柱塞泵中存在的一些不可避免的缺陷，提出了能避免这些缺陷的二维燃油泵。通过解释二维燃油泵的结构组成与工作原理，说明了二维燃油泵的优势，包括结构力平衡、工作效率高、无直接的滑动摩擦副和无结构性流量脉动等。为了解释无结构性流量脉动这一优点，进行了仿真分析与实验验证，验证了二维燃油泵具有无结构性流量脉动这一潜力。     

L15高教机液压脉动超标原因分析及解决方法

通过对L15高教机首飞前液压系统机上脉动试验中出现零流量压力脉动超标及传感器接头损坏的分析,找出了故障原因,并有针对性地采取了排除措施,即在飞机上调整液压系统阻抗及机械震动固有频率,改变软管安装方式等,以减少飞机液压脉动值,使飞机脉动在航标规定范围内.文中还探讨了抑制液压脉动的各种方法,并比较了各种不同方法的优劣,得出...     

航空发动机内啮合摆线齿轮泵高空特性数值研究

高空性是评价航空发动机齿轮泵性能的关键参数之一,为了获得摆线泵的高度特性曲线,并分析其影响因素,采用三维非定常数值模拟的方法,应用动网格技术对单级内啮合摆线齿轮泵的高空特性进行定量分析。结果表明:随着飞行高度增加,摆线泵内的空化现象加剧,供油流量减少;当飞行高度在8km以上时,容积效率随高度上升而急剧下降,且在相同的出口条件下,低转速摆线泵的容积效率明显高于高转速工况;当飞行高度在8km时,增大摆线泵出口压力,出口流量脉动幅度由时均流量的16%增至20%,且出口流量的脉动频率随摆线泵的转速加快而变大。所以,摆线泵在高空工作时,降低转速即可以满足供油需求,同时减少系统负担。     

喷前压力脉动对撞击式喷嘴雾化特性的影响

为研究液体火箭发动机供应系统压力脉动对撞击式喷嘴雾化特性的影响,进行了撞击式喷嘴的动态雾化实验。通过脉动装置在喷嘴供应系统上施加不同频率和幅值的周期性压力脉动,利用两套高速摄影系统分别获得了动态雾化图像和雾场横截面上的散射光强,以此分析了撞击式喷嘴对喷前周期性压力脉动的响应频率和响应幅值范围及其对平均雾化角度的影响。结果表明,在研究的脉动频率范围内(0~4050Hz),当喷前压力脉动幅值大于某一阈值后,雾化出现了明显的周期性质量聚集现象,其频率与喷前压力脉动的频率相同。脉动幅值增加,散射光强度的振荡幅值也增加,参与混合燃烧过程的介质流量振荡幅值加剧。平均雾化角度受脉动频率和幅值的影响都较小,变化范围处在均值的±4%以内。     

管内激波串振荡和壁面脉动压力特性

分析了管内激波串振荡引起的壁面压力脉动特性。采用直联风洞实验方式结合动态压力测量技术获得了矩形管道内不同激波串位置下的壁面压力分布数据,对所得压力脉动幅值、功率谱密度曲线等结果进行分析,探讨激波串流动非定常特点与引起压力脉动的机制。     

双泵并联供压液压系统频域仿真研究

一、前言 在飞机和一般工业中,多泵并联供压液压系统是很常见的。研究动态仿真,对提高它们的动态品质是至关重要的。 泵源的脉动流量输入到液压系统中,在遇到负载阻抗后形成压力脉动。在泵源和负载的阻抗匹配后,可产生谐振现象,形成强烈的压力流量脉动,并引起液压系统的机械振动,严重者将造成元、部件的破坏。研究谐振问题的最方便的方法是频率法。     

Fault diagnosis of an intelligent hydraulic pump based on a nonlinear unknown input observer

Hydraulic piston pumps are commonly used in aircraft. In order to improve the viability of aircraft and energy efficiency, intelligent variable pressure pump systems have been used in aircraft hydraulic systems more and more widely. Efficient fault diagnosis plays an important role in improving the reliability and performance of hydraulic systems. In this paper, a fault diagnosis method of an intelligent hydraulic pump system (IHPS) based on a nonlinear unknown input observer (NUIO) is proposed. Different from factors of a full-order Luenberger-type unknown input observer, nonlinear factors of the IHPS are considered in the NUIO. Firstly, a new type of intelligent pump is presented, the mathematical model of which is established to describe the IHPS. Taking into account the real-time requirements of the IHPS and the special structure of the pump, the mechanism of the intelligent pump and failure modes are analyzed and two typical failure modes are obtained. Furthermore, a NUIO of the IHPS is performed based on the output pressure and swashplate angle signals. With the residual error signals produced by the NUIO, online intelligent pump failure occurring in real-time can be detected. Lastly, through analysis and simulation, it is confirmed that this diagnostic method could accurately diagnose and isolate those typical failure modes of the nonlinear IHPS. The method proposed in this paper is of great significance in improving the reliability of the IHPS.     

宽频高幅值水力激振信号的产生与控制

为了研究火箭发动机全尺寸泵后供应系统的动力学特性,运用脉动压力发生器设计了一种宽频水力激振系统,开展了液流试验和数据分析。结果表明:水力激振系统可以在0~1200Hz的频率范围内,产生时域幅值超过1.5MPa、高信噪比的压力脉动信号,达到了宽频率范围、高激励幅值的目的。通过对电动机转速的控制实现激励频率的可控变化,以满足不同频率激励策略的要求。提高管路系统的入口稳态压力,可以提高激振信号的幅值。通过合适的局部流阻分布,可以在宽频范围内提高水力激振信号的幅值,提高信噪比。      

Hydraulic piston pump in civil aircraft: Current status,future directions and critical technologies

The piston pump is the key power component in the civil aircraft hydraulic system, and the most common pump used in the aviation field is the pressure compensated variable displacement type. In this review paper, a basic introduction to the civil aircraft piston pump is presented, including the classification, structure, working principle, design features, and achievements by some research groups. Then, the future directions of the aircraft pump are reported from various perspectives. Further, the critical technologies are analyzed and summarized in detail from six thrust areas: friction couples, noise reduction, inlet boost, thermal management, fault diagnosis and health management, and mechanical seal. Finally, the challenges and limitations of the research on the aircraft pump are discussed to provide valuable insight for future scholars.     

Review of cylinder block/valve plate interface in axial piston pumps: Theoretical models,experimental investigations,and optimal design

Axial piston pumps have been widely used in aircraft hydraulic systems to supply the system with pressurized fluid. The continuous improvement of the aircraft performance has put forward the demand on aviation piston pumps for high power density, safety, and reliability. The lubricating interfaces in axial piston machines are the key design issue that greatly determines the pump performance and service life. The cylinder block/valve plate interface is one of these critical lubricating interfaces and has received considerable attention from many researchers in the last half century. This study aims to review the state‐of‐the‐art literature on the cylinder block/valve plate interface comprehensively and systematically. First, we introduce various theoretical models developed to investigate the lubrication behaviors of the interface and compare them in terms of their assumptions and limitations. Second, the experimental studies on the cylinder block/valve plate interface are presented comprehensively, where the involved test rigs are divided into three types according to their fidelity levels and measurement functionality. Third, we summarize some typical approaches of structure optimization, surface shaping, and surface strengthening, which help improve the load-carrying and anti-wear capacities of the interface under severe operating conditions. Finally, the challenges and future trends of the cylinder block/valve plate interface research are discussed briefly.     

基于旁路溢流原理的流体脉动主动控制

 随着现代飞机液压系统向高压、大功率方向发展，周期性流体脉动更容易在液压能源系统中产生流固耦合振动，导致液压管路疲劳破坏。针对被动式流体脉动抑制方法不具备自适应性、对低频脉动抑制效果差等缺点，提出了基于旁路溢流原理的流体脉动主动控制方法，即在与能源主管路连通的分叉管路上安装压电陶瓷驱动伺服阀主动消振器，通过主动消振器的溢流产生次级脉动波与主管路中原有压力波相互抵消，使管路中流体脉动减小。并针对流体脉动周期性特点，提出一种在线频率估计的自适应前馈控制方法，利用参考传感器测量泵源脉动信号，在线获取脉动频率，并以此频率构造控制器的参考输入信号，实现对流体脉动的主动控制。为验证所提方法的有效性，设计了主动消振实验平台。实验结果表明，所提出的脉动主动控制方法具备很强的自适应性，能对流体脉动进行很好的抑制。     

Modeling and Optimal Design of 3 Degrees of Freedom Helmholtz Resonator in Hydraulic System

Three degrees of freedom (3-DOF) Helmholtz resonator which consists of three cylindrical necks and cavities connected in series (neck-cavity-neck-cavity-neck-cavity) is suitable to reduce flow pulsation in hydraulic system. A novel lumped parameter model (LPM) of 3-DOF Helmholtz resonator in hydraulic system is developed which considers the viscous friction loss of hydraulic fluid in the necks. Applying the Newton’s second law of motion to the equivalent mechanical model of the resonator, closed-form expression of transmission loss and resonance frequency is presented. Based on the LPM, an optimal design method which employs rotate vector optimization method (RVOM) is proposed. The purpose of the optimal design is to search the resonator’s unknown parameters so that its resonance frequencies can coincide with the pump-induced flow pulsation harmonics respectively. The optimal design method is realized to design 3-DOF Helmholtz resonator for a certain type of aviation piston pump hydraulic system. The optimization result shows the feasibility of this method, and the simulation under optimum parameters reveals that the LPM can get the same precision as transfer matrix method (TMM).     

RANS/LES在超声速突起物绕流中的应用研究

安装在超声速/高超声速飞行器表面的突起物如机翼、控制舵等通常会导致复杂的激波/边界层干扰,对突起物的局部气动特性甚至飞行器整体的气动特性产生较大的扰动.在采用计算流体力学(CFD)数值模拟此类问题时,传统的求解雷诺平均Navier-Stokes(RANS)方程方法由于不能准确预测湍流脉动流场并且精度有限,在应用上受到一定的限制.本文在研究B-L (Baldwin-Lomax)内层模型和Smagorinsky亚格子模型优缺点的基础上,提出了一种新型的RANS/LES(Large Eddy Simulation)混合模型,并进行了算例验证,证实了该方法的可行性.在此基础上,对火箭表面突起物的干扰流场进行了数值模拟研究,细致地刻画了突起物附近的激波/边界层干扰、剪切层失稳和底部分离涡形成的非定常过程,获得了突起物及火箭表面上的压力脉动历程并进行了频谱分析.研究发现,相对于突起物底部的非定常分离流动,突起物前缘的激波和边界层相互干扰的非定常过程是突起物周围压力脉动的主导因素,这种高频的压力脉动可能对火箭内设备的正常工作产生不利的影响.     

Numerical investigation of effect of a centrifugal boost impeller on suction performance of an aircraft hydraulic pump

An integrated boost impeller can effectively improve the suction performance of an aircraft hydraulic pump (AHP). It must be designed very carefully; however, few studies thus far have investigated boost impellers. To explore the effect of the boost impeller, this study developed a three-dimensional computational fluid dynamics (CFD) model for an AHP based on the k-ε turbulence model and full cavitation model. The results of verification tests demonstrated that the model is reliable for simulating the delivery characteristics of piston pumps and the boost capacity of the inlet impeller. Steady-state simulations reveal that the boost impeller can remarkably improve the suction performance and mitigate the cavitation damage due to insufficient fluid filling while only consuming a small proportion of the total input power. Transient-state simulations show that the pump with an impeller is more capable of catching up with a sudden increase in flow demand, and it has a lower suction flow ripple and impact. However, such a boost impeller also has some limitations such as magnifying the suction pressure fluctuation and having little effect on mitigating the cavitation caused by the back-flow jet.