压力传感器寿命考核电液脉冲试验台水锤波仿真分析

梳理电液脉冲试验台的脉冲发生原理,选取水锤脉冲波形对压力传感器进行寿命考核,建立水锤波脉冲发生仿真模型,改变模型中油液性质、试验件容积、比例电磁阀输入电流、管路管径等参数对系统进行脉冲仿真分析.仿真结果表明:电液脉冲系统受多个分布参数影响,对预期产生波形均有不同程度关联,设计中应综合考虑阀门过流能力、试验件的容积及沿程...     

差压传感器在发动机喷油嘴密封性检测上的应用研究

提出基于差压传感器的发动机喷油嘴密封性检测系统方案,采用气缸带动测试管路连接在发动机喷油嘴进口上,同时将喷油嘴所在管路与密封的平衡测试管路分别连接在差压传感器两侧.根据检测需要由气压管路分别向喷油嘴和所在管路和平衡测试管路通入压缩空气,利用压力传感器检测反馈系统压力值.当气压达到要求压力时,切断差压传感器两侧的管路,在规定时间内检测喷油嘴的泄漏量,与要求数值比较判断合格与否.实验研究表明:系统的检测效率高,并可以长期稳定运行.     

电力机车空气管路温控系统设计

针对电力机车空气管路发生冻结这一现象,设计了一套加热解冻及防冻结系统,采用热电阻传感器作为感温元件进行温度测量,单片机作为控制器进行数据处理及运算,采用可控硅MOSFET28N05L来控制加热器进行工作,将PWM波加在晶闸管上,以其周期性的通断来控制加热回路的强电。为了方便调试,设计了友好的人性化界面。本研究为电力机车空气管路系统防冻结提供了一种参考方案。     

气体脉动试验系统研究

为了实现水锤波等多种波形控制,适用贵重或有毒介质的产品脉动试验需求,采用气体扩散平衡原理,通过伺服阀流量控制与反馈,结合多级压力储气容器的容积匹配设计,并通过增压及泄放复合方式,实现脉动频率可调。文中设计了一种适用于低于0.2 L试验腔体的脉冲试验系统,通过试验验证,在设定条件下,设备可实现100 000次可靠运行,设备噪声、波形拟合度均能满足压力传感器的脉动试验技术要求,且压力控制稳定。     

基于差压传感器和LabVIEW的真空助力器主缸泄漏量检测系统研究

根据检测需要由气压管路分别向助力器主缸及所在管路和平衡测试管路通入压缩空气或是由测试管路与大气压进行比对,利用压力传感器检测反馈系统压力值.当气压达到要求压力时,切断差压传感器两侧的管路,在规定时间内检测助力器主缸的主缸泄漏量,与要求数值比较判断合格与否.实验研究表明:系统的流量泄漏检测精度为0.5ml/min,并可以长期稳定运行.     

液动控制活门关闭过程水锤分析与实验研究

在某型飞机飞行过程中,其燃油系统因液动控制活门关闭过程产生水锤效应,导致剧烈噪声并引发管路振动,严重影响飞行安全。通过分析系统工作原理并进行仿真计算后,提出调低射流传感器响应频率、降低活门匹配腔压力、缩小管路通径等方案解决了此问题。研究结果可以为液动控制活门系统水锤问题的解决及飞机燃油系统设计优化提供指导和借鉴。     

循环冲击作用下缺陷飞机液压管路微泄漏故障诊断

带有表面微缺陷的飞机液压管路在循环压力冲击作用下会逐渐形成非贯穿裂纹,但是随着裂纹处应力的循环作用,会扩展成贯穿性微裂纹,导致管路产生微泄漏。基于管路内瞬变流数学模型,采用AMESim软件对循环压力冲击载荷下飞机液压管路泄漏故障进行模拟,分析不同泄漏情况对管路压力信号波形的影响;然后根据管路压力信号波形的仿真结果,通过Daubechies小波系中5类小波函数分别对其进行小波分解,分析并对比小波函数的分解结果,选取最优小波函数分解结果定位信号中奇异点位置;最后开展管路泄漏故障实验,通过最优小波函数和负压波定位法检测及定位管路泄漏位置。研究成果为飞机液压管路泄漏故障诊断提供新的方法,同时,为我国飞机液压管路视情维修模式进行探索。     

硅电容差压传感器性能测试中PLC对压力的控制

原有硅电容差压传感器性能测试中压力控制方式完全采用人为操作,不仅耗时耗力,而且对性能测试的精度也存在无法估计的测试误差,为了避免这些弊端,提出了新的测试方案,该方案采用PLC 控制正、负腔管路中高压电磁阀和压力传感器的方式来实现对硅电容差压传感器性能测试过程中正、负腔管路的加卸压.这样便大大地节省了人力和时间,更加有效地提高了硅电容差压传感器性能测试效率.     

基于灰色预测PID的煤层气输送管路监控系统

提供一种煤层气输送管路监控系统设计方案,该方案应用PLC和操作员站实现管路压力、流量的监测、控制。由于长管路系统存在时滞且气体具有可压缩性,为满足送气点对于压力、流量的要求,引入灰色PID控制,通过管路沿途分布的传感器信息建立起灰色预测模型,对压力流量实现精确控制,仿真实验证明,该方法具有响应迅速、鲁棒性好的特点。     

油液传感器安装优化设计方法研究

燃油、滑油系统作为燃气轮机重要的附属系统。由于可靠性和安全性的需要,当前燃气轮机对燃油、滑油系统的外循环油液在线检测有迫切的需求,但是在已有的系统安装油液传感器,势必对原有油液系统产生管路压力损失影响。这可能导致油液压力降低,从而达不到原有设定的工作条件,而且还有可能造成供油泵的过载运行。因此,本文研究了两种油液传感器管路的安装方式,并分别分析了油液传感器安装方式对管路损失的影响,对局部损失和沿程阻力进行原理分析及建立数学模型;随后将油液管路压力损失最小设定为优化目标,建立相应油液传感器优化模型,采用黄金分割算法实现了管路优化设计。最后,利用本文的设计方案对工程实例进行了优化,得到最优传感器螺纹尺寸为21.96mm,根据工程需要设定传感器为25mm的螺纹,验证了本文方法的有效性。     

基于高压油管外卡油压信号的柴油机实时转速测量方法研究

柴油机高压油管油压波形中包含了大量可作为供油系统故障诊断的特征参数和转速变化的信息,本文介绍了利用柴油机高压油管油压波形信号提取柴油机转速这一重要参数的方法,建立外卡油压信号采集系统,运用巴特沃斯低通滤波器对测量的高压油泵油压信号进行二次处理,对提取的转速进行平均,实验表明,这种检测方法有技、可行.     

双工位燃油总管试验器喷嘴入口压力控制系统动态特性分析

给出了由液压泵、比例溢流阀、蓄能器、压力传感器以及节流口组成的双工位燃油总管试验器工件入口处闭环压力控制系统的原理图,建立了该系统的数学模型及Simulink仿真模型,提供了与试验器真实相符的控制参数,分析了其压力动态响应特性,并绘制了相应的响应曲线。     

水载压力对管道超声导波信号的影响研究

为了研究水载压力对管道超声导波信号的影响,利用半解析有限元的方法分析了管道导波的频散曲线和波结构,选择 L(0,2)模态导波用于实验验证。 设计了一个可承受 30 MPa 压力的防水卡箍,对管道上的压电传感器进行封装。 将安装了防 水耐压卡箍的管道放入压力舱中进行打压循环测试,压力在 0~ 30 MPa 之间变化。 打压过程中采集无损伤及 5% 损伤的管道超 声导波信号,分析水载压力对导波信号的影响。 实验结果表明,该防水卡箍具有良好的防水和耐压性能,水载压力对 L(0,2)模 态导波信号幅值没有显著影响。     

基于PLC的双恒压供水控制系统设计

该双恒压供水控制系统是以PLC控制为核心,变频调速技术为基础,并结合压力传感器、变频器、水泵、继电器、接触器等组成。在此系统中,PLC将压力设定值与测量值的偏差经PID运算后得到的控制量作用到变频器,从而通过变频器控制水泵的转速调节管网的压力,实现恒压供水的目的。     

基于时间反转法的管道焊缝区缺陷检测研究

焊缝在整个管网系统中是比较薄弱的部分,在温度、压力、介质腐蚀和振动的影响下容易出现裂纹缺陷,对管道的安全运行产生危害,并且有的裂纹很小,通过超声导波不容易直接识别出来。对超声导波检测管道进行了研究,在分析了超声导波对焊缝小缺陷的检测后,提出了一种运用时间反转法基于L(0,2)模态超声导波进行数值模拟的方法,选择4%作为最小焊缝裂纹缺陷,对直管道单焊缝和直管道双焊缝进行数值模拟,并通过实验验证。数值模拟和实验结果表明该方法可以实现管道中焊缝缺陷的识别和定位。     

Lamb波压差式微流量传感器

为提高微流体系统中的流量检测灵敏度,增大动态检测范围,实现温度补偿,提出了一种基于Lamb波的压差式微流量传感系统.该传感系统主要由两个Lamb波压力传感器和微通道组成,它利用Lamb波薄膜内应力的敏感特性,以频率计量的方式间接测量微通道两端的压力差;并采用双Lamb波压力传感器构成差动式测量结构进行温度补偿.对长20 mm,宽1 mm,高50 μm的微通道进行了流量测试实验,结果表明:在流量测试范围内,微通道两端的频率差与流量基本呈线性变化,其线性相关系数为0.999 9;在微流量传感器未进行优化的前提下,最小检测量为0.627 μL/s.     

Development of Adaptive Fill Control for Multitorch Multipass Submerged Arc Welding

A significant portion of the total manufacturing time for a pipe fabrication process is spent on the welding following the primary machining and fit-up processes. To achieve a reliable weld bead appearance, automatic seam tracking and adaptive control to fill the groove are urgently required. For seam tracking in the welding processes, vision sensors have been successfully applied. However, the adaptive filling control for a multitorch system for the appropriate welded area has not yet been implemented in the area of submerged arc welding (SAW). This paper describes several advances in sensor and process control techniques for applications in SAW which combine to give a fully automatic system capable of controlling and adapting the overall welding process. This technology has been used in longitudinal and spiral pipe mills and in pressure vessel production.     

Natural Characteristic of Thin-Wall Pipe under Uniformly Distributed Pressure

Natural characteristics of thin?wall pipe of the compressor under uniformly distributed pressure were presented in this paper based on a cylindrical shell model. In the traditional method, the beam model was usually used to analyze the pipe system. In actual fact, the pipe segment of the compressor was always broken in the form of a long crack or a partial hole and the phenomenon was hardly explained by beam model. According to the structure characteristic of compressor pipe segment, whose radius is large and thickness is little, shell model shows the advantage in this kind of pipe problem. Based on Sanders' shell theory, the vibration di erential equation of pipe was established by apply?ing the energy method. The influences of length to radius ratio(L/R), thickness to radius ratio(h/R), circumferential wave number(n) and pressure(q) on the natural frequencies of pipe were analyzed. The study shows: Pressure and structural parameters have a great e ect on the natural characteristics of the pipe. Natural frequency increases as the pressure increases, especially for the higher mode. The sensitivity of natural frequency on pressure becomes stronger with h/R ratio increases; when L/R ratio is greater than a certain critical value, the influence of the pressure on natural frequency will no longer be obvious. The value of n corresponding to the minimum natural frequency also depends on the value of pressure. In the end, analysis of the forced vibration of a specific pipeline model was given and the modal shapes were illustrated to understand the break of the pipe. The research here will provide the theory support for the dynamic design of related pressure pipe and further experiment study should be employed.     

Fundamental guided wave attenuations and sensor location estimation in fluid-filled steel pipes

The sound intensities required to sustain a certain interval between two ultrasonic sensors that are installed outside a steep pipe for structural health monitoring are numerically investigated. Two fundamental guided wave modes, longitudinal and flexural, are considered for the calculation of their attenuations via the concept of parametric density and a sink inside steel pipes, and these attenuations are used for the sound-intensity calculations. The results, attenuations, and sound intensities are useful as a guideline when guided-ultrasonic-wave-based inspection is planned for pipeline maintenance and safety, especially for estimation of the axial location between ultrasonic sensors. The text was submitted by the authors in English.     

Concentration and pressure measurements of dense sand and gravel multiphase flows under transient flow conditions in a vertically oriented closed conduit — Assessment of system and sensor performance

The hydraulic transport of sediments in sediment–water multiphase mixtures is an important process in nature and many industrial applications. The flows are characterized by complex transient phenomena, in which the overall system scale and the particle scale are equally important. Experimental research into dense mixture flows is focused on measurement of flowrates, differential pressures and concentrations of the suspended sediments.Concentration measurements are especially challenging in the case of coarse particles (beyond millimeter size scale) flowing in dense mixtures, limiting the range of available sensors for accurately measuring the in-situ solids concentrations. For the investigation of transient processes, a quick sensor response is required, which makes concentration measurement based on mixture conductivity an interesting option.This study is focused on combined concentration and pressure measurements in dense sediment–water mixtures with coarse particles in a vertically oriented closed conduit, using differential pressure sensors over the vertical segments and conductivity probes for measuring the mixture concentration. We experimentally investigated the dispersion process of an initially densely packed batch of sand and gravel by measuring the concentration on different segments of the conduit, resulting in data on mixture wall shear stresses for different sand and gravel mixtures and data of attenuation of concentration gradients in vertical upward and downward flow, in the conduit horizontal top section and in the centrifugal pump.We describe in the detail the sensor calibration and data processing method, giving a best practice for the use of conductivity concentration sensors in dense coarse particle mixtures, and we suggest a novel method for analysis of density wave amplification and attenuation based on concentration measurements in general, which allows for the detailed analysis of transient multiphase flow phenomena at pipe system component level.