RESEARCH ON THE PERFORMANCE OF NEW TYPE OF PROPORTIONAL PESSURE AND FLOW CONTROL VALVE

A new closed loop flow controlling principle through correcting the valve'sopening area while load pressure is changing is carried out. Further more a principle using only oneproportional valve to compound control pressure and flow is suggested. By using very simpleproportional throttle valve in structure, the functions that five kinds of proportional valves orany two of them combined possess can be complimented. After analyzing, comparing, and testing thedynamic and static characteristics of valve with different controlling principles and main valvestructure styles, the optimized structure styles and control methods are achieved.

Pressure Regulating Pressure of A New Pressure Regulating Valve with Spring

A new type of pressure regulating valve for agriculture irrigation, which used spring to regulate pressure was studied. Through the spring regulating pres-sure test, it concluded that for the pressure regulating valve with same spring mod-el, the outer pressure became smal er than the inlet pressure of the system and with the changes of inlet pressure, the outlet pressure remained almost the same, and that when inlet pressure was constant, the valve with smal er spring diameter had lower outlet pressure, indicating that the pressure regulating effect of the spring was more obvious with smal er diameter.

Study on a Novel Digital Electro－Hydraulic Pressure Valve with a Capillary Damping Tube Regulating Pressure

A digital electro-hydraulic 4-port differential pressure control valve with a novel principle and structure is presented. The valve is designed by applying the regulating pressure technique of a capillary damping tube and also making full use of double freedom of the spool motion. Thevalve can implement digitizing interface easily. The theoretical analysis and experimental resultsshow that the valve is not only very simple in structure and convenient in use, but also has manygood properties, such as fast response, no-null-shift, etc.

Numerical Simulation of Oil and Gas Two-Phase Flow in Deep Condensate Gas Reservoirs in Bohai Buried Hills

The BZ19-6 gas field is characterized by high temperature and high pressure (HTHP), high condensate content, little difference between the formation pressure and dew point pressure, and large amount of reverse condensate liquid. During the early stage of depletion development, the production gas-oil ratio (GOR) and production capacity remain relatively stable, which is inconsistent with the conventional reverse condensate seepage law. In view of the static and dynamic conflict in development and production, indoor high-temperature and high-pressure PVT experiment was carried out to reveal the mist-like condensation phenomenon of fluids in the BZ19-6 formation. And the seepage characteristics of condensate gas reservoirs with various degrees of depletion under the condition of HTHP were analyzed based on production performance. The change rule of fluid phase state was analyzed in response to the characterization difficulties of the seepage mechanism. The fluid state was described using the miscible mechanism. And the interphase permeability interpolation coefficient was introduced based on interfacial tension. By doing so, the accurate characterization of the “single-phase flow of condensate gas-near-miscible mist-like quasi single-phase flow-oil-gas two-phase flow” during the development process was achieved. Then the accurate fitting of key indicators for oilfield development was completed, and the distribution law of formation pressure and the law of condensate oil precipitation under different reservoir conditions are obtained. Based on research results, the regulation strategy of variable flow rate production was developed. Currently, the work system has been optimized for 11 wells, achieving a “zero increase” in the GOS of the gas field and an annual oil increase of 22,000 cubic meters.

Motion-pressure coupled control and simulation of long-endurance capability for multicapsule stratospheric airships

The current study focuses on the motion-pressure coupled control for a multicapsule stratospheric airship and transforms the path-tracking and heading-hold control of airships into guidance tracking with a time-varying weighted sum of longitudinal and lateral velocities by the definition of compound speed.Herein,an improved nonlinear predictive control method is provided to reduce the control energy consumption by the rolling optimization of controller parameters based on finite time intervals,ensuring infinite-time path-tracking tasks.Simultaneously,combined with the proposed cyclic regulation process of safe pressure between internal and external capsules,this study can fully reflect the force-thermal coupled rule of airships under the actions of atmospheric environment and maneuvering force,while evaluating the long-endurance capability of airships under the conditions of safe superheating and overpressure.The effectiveness of the motionpressure coupled controller was verified through numerical simulations,which can overcome the influence of environmental wind and achieve a tracking effect for the desired cruise path and compound speed.The airspeed provided during the cyclic circadian time caused the maximum superheating of the helium controlled within 30C.The helium in the internal and external capsules achieved circadian regulation.The equivalent micropore diameter of the capsule of 5 mm can achieve 55 days of long-endurance flight.The controller satisfies the requirements of cruise-flight application modes for multicapsule stratospheric airships with important engineering value.

Pressure Regulation for Earth Pressure Balance Control on Shield Tunneling Machine by Using Adaptive Robust Control

Most current studies about shield tunneling machine focus on the construction safety and tunnel structure stability during the excavation. Behaviors of the machine itself are also studied, like some tracking control of the machine. Yet, few works concern about the hydraulic components, especially the pressure and flow rate regulation components. This research focuses on pressure control strategies by using proportional pressure relief valve, which is widely applied on typical shield tunneling machines. Modeling of a commercial pressure relief valve is done. The modeling centers on the main valve, because the dynamic performance is determined by the main valve. To validate such modeling, a frequency-experiment result of the pressure relief valve, whose bandwidth is about 3 Hz, is presented as comparison. The modeling and the frequency experimental result show that it is reasonable to regard the pressure relief valve as a second-order system with two low corner frequencies. PID control, dead band compensation control and adaptive robust control（ARC） are proposed and simulation results are presented. For the ARC, implements by using first order approximation and second order approximation are presented. The simulation results show that the second order approximation implement with ARC can track 4 Hz sine signal very well, and the two ARC simulation errors are within 0.2 MPa. Finally, experiment results of dead band compensation control and adaptive robust control are given. The results show that dead band compensation had about 30° phase lag and about 20% off of the amplitude attenuation. ARC is tracking with little phase lag and almost no amplitude attenuation. In this research, ARC has been tested on a pressure relief valve. It is able to improve the valve＇s dynamic performances greatly, and it is capable of the pressure control of shield machine excavation.

Application of Single Neuron Adaptive PID Regulators with Auto-tuning Gain in Industrial Parameter(Pressure)Closed-loop Process Control Systems

A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of induStrial parameter closed-loop process controlsystems is improved, and the work quality of the systems bettered.

Water hammer prediction and control:the Green's function method

By Green＇s function method we show that the water hammer （WH） can be analytically predicted for both laminar and turbulent flows （for the latter, with an eddy vis- cosity depending solely on the space coordinates）, and thus its hazardous effect can be rationally controlled and mini- mized. To this end, we generalize a laminar water hammer equation of Wang et al. （J. Hydrodynamics, B2, 51, 1995） to include arbitrary initial condition and variable viscosity, and obtain its solution by Green＇s function method. The pre- dicted characteristic WH behaviors by the solutions are in excellent agreement with both direct numerical simulation of the original governing equations and, by adjusting the eddy viscosity coefficient, experimentally measured turbulent flow data. Optimal WH control principle is thereby constructed and demonstrated.

Flow-rate Characteristics Measurement of Regulators Based on the Pressure Response in an Isothermal Tank

Regulators are important components in pneumatic system, and their flow-rate characteristics are the key parameters for designers. According to the correlatively international standard and national standard of China, which describe the flow-rate characteristics measurement method of pneumatic regulators, the pressure and the flow are measured point by point, and then the flow-rate characteristics curve is plotted point to point. This method has some disadvantages, such as equipment complexity, much air consumption, and low efficiency. To settle the problems presented above, this paper puts forward a new high efficient and energy saving flow-rate characteristics measurement method of regulators, which is based on the pressure response when charging and discharging to an isothermal tank without any flow meters. The measurement principle, the system and the steps are introduced. And the tracking differentiator is used for the data processing of the pressure difference. Two typical kinds of regulators were experimentally investigated, and their flow-rate characteristics curves were obtained with the new and the conventional method, respectively. Comparatively, it＇s proved that this new method is feasible because it is not only able to meet the demand of the measurement precision, but also to save energy and improve efficiency. Compared to the conventional method, the new method takes only about 1/10 amount of time and consumes about only 1/30 amount of air. Hopefully it will be able to serve as an international standard of flow-rate characteristics measurement method of regulators.

典型控流调压阀后突扩体的压力特性

为了研究突扩体对控流调压阀门的增压减振作用,以典型控流调压阀门(活塞式调流阀和固定式锥形阀)为研究对象,采用物模试验和三维数值模拟相结合的研究方法,重点对2类阀门在不同突扩体型、阀门开度及空化强度下的阀后流态及管壁压力特性进行了观测分析,探究突扩比与阀后稳定压力的定量关系,试验阀门通径为150 mm,阀门直径为150~370 mm,突扩体长度为1000 mm.结果表明,突扩体能提升阀后管壁时均压力、减弱压力脉动的基本原理是水垫层效应.综合物模与数模试验结果,拟合得到了突扩比与阀后管壁稳定时均压力的关系式.突扩体可以提升阀门的工作背压,提升程度随突扩比的增大而渐缓.当突扩比为4.00时,阀后管壁稳定时均压力的增幅已非常平缓,趋于稳定.不同阀型试验结果差异小,说明突扩体的增压减振作用具有普适性.研究结果可供输水调压工程阀门段管道系统设计参考借鉴.

高压氧舱恒湿平压系统的设计

目的:设计一种高压氧舱恒湿平压系统,以消除舱内静电火花造成的危害,保证氧舱的安全运行。方法:该系统的硬件主要由加湿装置、除湿装置、平压装置、主控制器、压力传感器、温湿度传感器等组成。其中,加湿装置主体为经过特殊加工后的防爆过滤瓶;除湿装置采用工业级风机过滤单元(fan filter unit,FFU),由蒸发器、冷凝器、风轮3个部分组成;平压装置主要由电磁阀和减压管路组成;主控制器选用EX3G-C系列PLC触摸屏一体机,温湿度传感器选用NWSF-1AT型号温湿度传感器,压力传感器选用TXYS-G1K2HN3型变送器。系统的软件控制程序采用指令表语言编程,通过PID(proportional-integral-derivative)控制算法实现整体控制。结果:经过测试,该系统可使高压氧舱内相对湿度恒定在70%,使舱内极难产生静电。结论:该系统能够调节氧舱内的湿度、减少静电火花产生,保证舱内治疗的安全。

双芯移相变压器在主动配电网电压和潮流调控中的应用分析

双芯移相变压器可以有效控制线路电压和潮流,优化潮流分布,提高电网电能质量。针对分布式电源的高比例接入造成的主动配电网电压波动和偏差问题,以及对潮流大小、方向和均衡度的影响,文章研究了双芯移相变压器的拓扑结构和工作原理;然后分析了串联变压器和励磁变压器的具体结构和作用,梳理了移相变压器分别应用于电压调节和潮流控制时的档位控制策略;最后基于MATLAB/Simulink建立了详细的仿真模型,研究了双芯移相变压器的电压调节效果,并对双线路并联、两路电源并联供电、多路电源并联供电三种应用场景下的潮流控制效果作了比较。仿真结果表明,双芯移相变压器可以在有限的档位内将线路电压控制在允许范围;与双线路并联、多路电源并联供电应用场景相比,两路电源并联供电时的潮流均衡效果最好,潮流偏差最小,本研究为双芯移相变压器的广泛应用提供了参考。

旁通阀结构对燃料电池系统阴极压力控制效果的分析

为减小压力波动对燃料电池寿命的不利影响,通过仿真及对比试验,探究增加旁通阀对阴极供给系统压力波动的改善效果。根据对燃料电池输出特性与各组件工作原理的分析,建立机理与控制模型;采用基于自抗扰的反向解耦方法实现流量与压力的解耦控制;运用模糊PI方法实现压力波动控制。通过Matlab/Simulink仿真验证了解耦方法在该系统结构下的控制效果,在对比试验中,压力波动峰值分别为无旁通阀1.82kPa与有旁通阀1.09kPa,旁通阀的增加减小了压力波动,使阴极流道压力的稳定性得到了更有效的控制,对提升燃料电池寿命有重要意义。

天然气调压橇故障分析处理

随着海外油田区块的开发,油田企业投资建设燃气轮机电站,将伴生气转化为油田生产所需的电能。由于规划中的天然气处理厂尚未建成,伴生气处理装置还不完善,伴生气含杂质多,经常出现天然气调压橇压力失调故障,直接影响燃气轮机安全运行。通过对两个不同厂商天然气调压橇的构成及调压阀工作原理的分析,分别提出采用油田伴生气调压橇的改造方案和厂商提供的指挥器装配错误修正方法,可保证燃气轮机在加速控制、一次调频、孤岛模式等工况下,天然气调压橇调整压力迅速、平稳,为海外油田区块原油产量上产稳产提供了技术支撑。

风速可调的地空一体化风力灭火遥控机结构设计与性能分析

风力灭火遥控机作为地面灭火装备的一种创新形式,具备机动性强、远程操作、快速响应等特点,能够在复杂的火情环境中灵活作业,大大提高了灭火效率和安全性。为探讨风力灭火遥控机在应对森林和草原地表火灾地空一体化监测系统中的角色与作用,对风力灭火遥控机进行结构设计,分析旋转开合结构的安装位置和开口大小对出口风速的影响。利用Fluent软件对风力灭火筒进行流体仿真,结合Design Expert软件对仿真数据进行处理,建立了位置S和开口大小d对出口平均风速和出口最大风速的响应曲面和二次模型。结果表明,安装位置和开口大小均为出口风速的重要影响因素,当风筒入口风速设定为70 m/s、旋转开合结构开口大小为30 mm且安装在位置5处时,出口平均风速和出口最大风速达到最大,分别为97.7551 m/s和290.001 m/s。相较于开口大小,安装位置对出口平均风速和出口最大风速的影响更大,且安装位置越靠近风筒出口处风力灭火机的灭火性能越好。

AGM隔板的装配压力对阀控式铅酸蓄电池性能的影响

研究了AGM隔板的注液量、注液种类、纤维直径、增强隔板以及初始压力等因素对装配压力的影响。实验证明,注液量为饱和吸液量的90%,装配压力控制在60 kPa左右,可以明显改善阀控式铅酸蓄电池的循环寿命。

双层合采油井盲管控水机理数值模拟

依托胜利油田盲管控水先导开发试验项目,根据双层合采油井油水流入动态特征,建立了双层合采油井盲管控水模型,并利用Fluent软件开展不同长度与不同位置盲管作用下的双层合采油井地层产液特征数值模拟研究。结果表明:盲管可以增加高含水层的井底流压,降低地层产液流量。对于综合含水率达到80%的双层合采油井,盲管长度是影响其控水效果的主要因素,盲管越长,控水效果越明显。与无盲管相比,在2 m的高含水层全段放置盲管,产液含水率可降低30百分点。盲管位置是影响其控水效果的次要因素,在2 m的高含水层不同位置放置0.5 m盲管,产液含水率下降约3百分点。为保障控水效果,应针对高含水层所在位置,放置适应地层厚度的盲管,调控双层合采油井产液流量,达到控水的目的。在优化双层合采油井盲管长度和盲管位置的基础上,利用流体数值模拟对盲管的控水机理进行了深入研究,研究结果能为高含水油藏双层或多层合采油井实施盲管控水开采提供技术指导。

电站调节阀阀体结构参数对流阻特性的影响

为了系统研究阀体结构参数对调节阀流阻特性的影响,采用数值模拟的方法,建立电站调节阀阀体模型,结合正交试验设计,研究调节阀阀体不同结构参数对流阻特性的影响。结果表明:调节阀阀体的结构参数对流阻系数的影响程度依次为上腔半径>下腔高度>上腔高度>阀体半长>下腔半径>中腔半径,同时再对阀体的入口角度进行优化分析,得到入口角度越小,流阻系数越小。通过正交实验优化和入口角度优化后得到的最优结构,其流阻系数与原结构相比降低了19.45%,且流量特性曲线也更加理想。研究成果能够为套筒式调节阀的结构优化提供理论支持。

基于模糊神经网络的氢液化氦气压力PID控制

为了解决氢液化装置氦气压力调节系统超调量大、响应速度慢、调节时间长、控制参数无法在线整定等问题,针对系统具有非线性和时变性的特点,设计了基于模糊神经网络的PID控制器以及基于双曲正切函数的改进型激活函数。仿真结果表明:相比传统PID控制或模糊PID控制,采用模糊神经网络PID控制的系统动态性能显著改善,使得氢液化装置的氦气压力调节更加稳定可靠。

混合式潮流控制器关键参数设计与控制策略研究

随着分布式光伏等新能源接入电网的规模快速增长,给新能源电力汇聚、疏散、消纳和电网潮流优化控制带来严峻挑战。基于电力电子技术的柔性交流输电系统装置可有效提升输电网络的传输容量,由大容量Sen变压器(sen transformer,ST)和小容量统一潮流控制器(unified power flow controller,UPFC)组成的混合式潮流控制器(hybrid unified power flow controller,HPFC)在实现潮流连续调节的基础上,能够有效提升装置的经济性,具有很好的应用前景。为了确保HPFC调节潮流的准确性和可靠性,给出了HPFC容量分配的一般性方法及其主电路参数确定方法;为解决ST机械有载分接开关和UPFC电力电子开关二者响应速度的协调问题,提出了一种基于预测电流控制的潮流控制策略,并在Simulink中搭建220 kV双回线路及三机九节点系统进行仿真。仿真结果验证了HPFC容量分配方法正确有效,且预测电流控制策略能够合理计算抽头位置,减缓过渡电流对HPFC控制系统的冲击,使系统功率快速调节至目标值。