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.

Modeling and Control of Time-pressure Dispensing for Semiconductor Manufacturing

To improve the consistency of the adhesive amount dispensed by the time-pressure dispenser for semiconductor manufacturing, a non-Newtonian fluid flow rate model is developed to represent and estimate the adhesive amount dispensed in each cycle. Taking account of gas compressibility, an intelligent model-based control strategy is proposed to compensate the deviation of adhesive amount dispensed from the desired one. Both simulations and experiments show that the dispensing consistency is greatly improved by using the model-based control strategy developed in this paper.

Effects of retrospective quality control on pressure-flow data with computer-based urodynamic systems from men with benign prostatic hyperplasia

Aim： To evaluate the effects of retrospective quality control on pressure-flow data with computer-based urodynamic systems from men with benign prostatic hyperplasia （BPH）. Methods： A total of 582 traces of pressure-flow study from 181 men with BPH was included in the study. For each trace, maximum urinary flow rate （Qmax） and detrusor pressure at Qmax （pdet.Qmax） were, respectively, read from manually smoothed and corrected uroflow and detrusor pressure curves from the computer print-outs. Obstruction coefficient, International Continence Society （ICS） and Schaefer nomograms were used to detect urethral resistance and to diagnose obstruction. The results obtained by manual reading were compared with those from computer-based systems. Results： After manual correction, Qmax underwent a consistently significant decrease by 1.2 mL/s on average （P 〈 0.001）, and had a change range of 0.5-10.4 mL/s. However, pdet.Qmax underwent inconsistently intra-individual changes after correction. The obstruction coefficient increased significantly, by an average of 0.07 （P 〈 0.05）. Using the ICS nomogram, the percentage of obstruction increased from 69.8% to 73.9%, and of the non-obstruction decreased from 8.8% to 5.3% （P 〈 0.05）. There were 11% of traces that changed the classifications using the ICS nomogram, and 28.9% that changed the grades for the Schaefer nomogram. Conclusion： Systematically significant differences in parameters from pres- sure-flow study between manual readings and computer recordings were demonstrated. Manual correction resulted in a consistently lower Q a higher urethral resistance, and an aggravating obstruction. Manual readings can correct considerable false diagnoses for obstruction. Retrospective quality control of pressure-flow data with com- puter-based systems is necessary.

High-precision nonisothermal transient wellbore drift flow model suitable for the full flow pattern domain and full dip range

A reliable multiphase flow simulator is an important tool to improve wellbore integrity and production decision-making.To develop a multiphase flow model with high adaptability and high accuracy,we first build a multiphase flow database with 3561 groups of data and developed a drift closure relationship with stable continuity and high adaptability.Second,a high-order numerical scheme with strong fault capture ability is constructed by effectively combining MUSCL technology,van Albada slope limiter and AUSMV numerical scheme.Finally,the energy equation is coupled into the AUSMV numerical scheme of the drift flow model in the form of finite difference.A transient non-isothermal wellbore multiphase flow model with wide applicability is formed by integrating the three technologies,and the effects of various factors on the calculation accuracy are studied.The accuracy of the simulator is verified by comparing the measurement results with the blowout experiment of a full-scale experimental well.

Numerical Investigation of Electrohydrodynamic (EHD) Flow Control in an S-Shaped Duct

An electrohydrodynamic （EHD） method, which is based on glow discharge plasma, is presented for flow control in an S-shaped duct. The research subject is an expanding channel with a constant width and a rectangular cross section. An equivalent divergence angle and basic function are introduced to build the three-dimensional model. Subsequently, the plasma physical models are simplified as the effects of electrical body force and work （done by the force） on the fluid near the wall. With the aid of FLUENT software, the source terms of momentum and energy are added to the Navier-Stokes equation. Finally, the original performance of three models （A, B and C） is studied, in which model A demonstrates better performance. Then EHD control based on model A is discussed. The results show that the EHD method is an effective way of reducing flow loss and improving uniformity at the duct exit. The innovation in this study is the assessment of the EHD control effect on the flow in an S-shaped duct. Both the parametric modeling of the S-shaped duct and the simplified models of plasma provide valuable information for future research on aircraft inlet ducts.

Experimental Study on Surface Dielectric Barrier Discharge Plasma Actuator with Different Encapsulated Electrode Widths for Airflow Control at Atmospheric Pressure

The surface dielectric barrier discharge （SDBD） plasma actuator has shown great promise as an aerodynamic flow control device. In this paper, the encapsulated electrode width of a SDBD actuator is changed to study the airflow acceleration behavior. The effects of encapsulated electrode width on the actuator performance are experimentally investigated by measuring the dielectric layer surface potential, time-averaged ionic wind velocity and thrust force. Experimental results show that the airflow velocity and thrust force increase with the encapsulated electrode width. The results can be attributed to the distinct plasma distribution at different encapsulated electrode widths.

Experimental and numerical investigation of a self-supplementing dual-cavity plasma synthetic jet actuator

The primary issue regarding the plasma synthetic jet actuator(PSJA)is its performance attenuation at high frequencies.To solve this issue,a self-supplementing,dual-cavity,plasma synthetic jet actuator(SD-PSJA)is designed,and the static properties of the SD-PSJA are investigated through experiments and numerical simulations.The pressure measurement shows that the SD-PSJA has two saturation frequencies(1200 Hz and 2100 Hz),and the experimental results show that both the saturation frequencies decrease as the volume of the bottom cavity of the SD-PSJA increases.As the size of the supplement hole increases,the first saturation frequency increases continuously,while the second saturation frequency shows a trend of first decreasing and then increasing.Numerical simulations show that the working process of the SD-PSJA is similar to that of the PSJA,but the volume of the cavity in the SD-PSJA is smaller than that of the PSJA;the SD-PSJA can supplement air to the top cavity through two holes,thus reducing the refresh time and effectively improving the jet intensity of the actuator at high frequencies.

Numerical Analysis of a Microjet-Based Method for Active Flow Control in Convergent-Divergent Nozzles with a Sudden Expansion

A method based on microjets is implemented to control the flow properties in a convergent-divergent nozzle undergoing a sudden expansion.Three different variants of this active control technique are explored numerically by means of a finite-volume method for compressible fluid flow:with the first one,the control is implemented at the base,with the second at the wall,while the third one may be regarded as a combination of these.When jets are over-expanded,the control is not very effective.However,when a favourable pressure gradient is established in the nozzle,the control becomes effective,leading to an increase in the base pressure.

Local dynamic balance theory and technology of flow field in multilayer gob area

Flow field in multilayer gob area, which formed in small hiden-depth, multi-coal layer groups, close distance, hard coal layer, and hard roof, possesses characteristics such as complex, changeable and unstable. Dynamic balance theory of local flow field in multilayer gob area was built based on the realistic requirement that the serious threat on current mining coal layer by large-scale spontaneous combustion fire on close spontaneous combustion coal layer group of Datong Coal mining area at the ＇di-hard＇ conditions was caused by small coal pit mining. The kernel was in dynamic balance between flow field pressures of working face and local flow field in multilayer gob area was kept by transformation. Corresponding technology and set of devices were developed.

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.

A New Device for Gas-Liquid Flow Measurements Relying on Forced Annular Flow

A new measurement device,consisting of swirling blades and capsule-shaped throttling elements,is proposed in this study to eliminate typical measurement errors caused by complex flow patterns in gas-liquid flow.The swirling blades are used to transform the complex flow pattern into a forced annular flow.Drawing on the research of existing blockage flow meters and also exploiting the single-phase flow measurement theory,a formula is introduced to measure the phase-separated flow of gas and liquid.The formula requires the pressure ratio,Lockhart-Martinelli number(L-M number),and the gas phase Froude number.The unknown parameters appearing in the formula are fitted through numerical simulation using computational fluid dynamics(CFD),which involves a comprehensive analysis of the flow field inside the device from multiple perspectives,and takes into account the influence of pressure fluctuations.Finally,the measurement model is validated through an experimental error analysis.The results demonstrate that the measurement error can be maintained within±8%for various flow patterns,including stratified flow,bubble flow,and wave flow.

Pressure control of PEMFC distributed power generator

Control design is important for PEMFC （proton exchange membrane fuel cell） distributed power generator to satisfy user requirement for safe and stable operation. For a complex multi-variable dynamic system, a dynamic simulation model is first established. In view of close coupling and non-linear relationships between variables, the intelligent auto-adapted PI decoupling control method is used. From the simulation results it is found that, by bringing quadratic performance index in the single neuron, constructing adaptive PI controller, and adjusting gas flow rates through the second pressure relief valve and air compressor coordinately, both anode and cathode pressures can be maintained at ideal levels.

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.

Wellbore drift flow relation suitable for full flow pattern domain and full dip range

Aiming at the simulation of multi-phase flow in the wellbore during the processes of gas kick and well killing of complex-structure wells(e.g.,directional wells,extended reach wells,etc.),a database including 3561 groups of experimental data from 32 different data sources is established.Considering the effects of fluid viscosity,pipe size,interfacial tension,fluid density,pipe inclination and other factors on multi-phase flow parameters,a new gas-liquid two-phase drift flow relation suitable for the full flow pattern and full dip range is established.The distribution coefficient and gas drift velocity models with a pipe inclination range of-90°–90°are established by means of theoretical analysis and data-driven.Compared with three existing models,the proposed models have the highest prediction accuracy and most stable performance.Using a well killing case with the backpressure method in the field,the applicability of the proposed model under the flow conditions with a pipe inclination range of-90°–80°is verified.The errors of the calculated shut in casing pressure,initial back casing pressure and casing pressure when adjusting the displacement are 2.58%,3.43%,5.35%,respectively.The calculated results of the model are in good agreement with the field backpressure data.

控压钻井实时计算及控制决策方法研究

随着石油勘探开发向边缘、深部复杂地区和非常规资源发展,窄密度窗口、高井控风险等钻井问题越来越突出。对于窄密度窗口地层,控压钻井能有效降低钻井作业难度和井控风险。但现有控压系统在无井底压力测量数据条件下的计算分析能力有限,无法实现准确指导常规控压钻井和精细控压作业实时计算分析与控制决策推荐。因此,基于现场工程录井、控压实时数据,建立了自动判断控压钻井作业工况的分支判断树,实现了11种钻井工况的实时识别。从环空液固两相流动特征着手,耦合井筒压力和地层流体侵入量,建立了控压钻井过程中的环空压力分布预测模型,实现了井口回压预控值的计算、确定和推荐。在理论研究基础上,开发了控压钻井计算分析及控制决策系统,现场测试表明:控压钻井过程中可以进行井筒压力及井口回压值模拟分析、自动识别钻井工况和井下复杂,立管压力的系统计算值与实测值之间平均误差为1.88%,基于安全作业条件的井口回压预测值与实控值符合率达到89.8%,实现了基于实时工程参数的控压钻井在线计算分析与控制决策,提高了控压钻井井口回压控制的可靠性和时效性,有效指导常规控压钻井作业,并通过流程优化提升了精细控压钻井作业能力和智能化水平。

具有变超越负载的液压调平系统负载口独立控制方法

液压调平系统平台回落过程中存在超越负载,且随着负载重心偏移和平台倾角变化,作用于支腿液压缸的负载力也会随之变化。传统液压系统中负载控制阀或平衡阀在平衡变超越负载时速度控制效果差,容易发生速度抖动。为解决这一问题,采用负载口独立控制技术,针对平台回落时液压缸存在的变超越负载工况,提出对液压调平系统中液压缸有杆腔进行压力控制,无杆腔进行流量控制的压力-流量复合控制方法,建立其数学模型,并进行AMESim和Simulink联合仿真验证。结果表明,在负载力发生突变时,液压缸有杆腔压力和无杆腔流量均可在0.2 s内恢复至控制值,平衡掉系统变超越负载的同时,能够满足系统的速度控制需求。

稀密两相状态监测实验平台设计

为了实际测量稀密两相对应的管道尺寸、风压和空气体积流量,设计了一个稀密两相状态监测实验平台。基于空气动力学理论和比例-积分-微分(PID)控制方法,将旁路调节系统应用到实验平台入口处,以控制管道入口空气体积流量,从而实现对物料稀密两相输送的实时监测与调控。该实验平台可实现稀密两相边界条件测试和流形稳定性分析等多项测试。最后,通过多次物料流形实验,验证了旁路调节系统在调控空气体积流量方面的有效性,以及气动测控系统维持物料流形的可行性。

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。

基于单片机开发板和3D打印的一种多参数呼吸训练装置的研究开发

目的通过野火骄阳32单片机开发板和3D建模及打印技术进行软硬件开发,实现一种多参数呼吸训练装置的专利样机转化。方法利用野火骄阳32单片机开发板开发应用程序,通过单片机开发板实现流量信号和压力信号的输入,舵机阀、涡轮风机、电磁阀的控制输出与上位机的数据通信等功能;样机非标零部件通过3D建模及打印技术完成制造,并将单片机开发板、标准零部件和非标零部件进行组合以完成样机开发。结果野火骄阳32单片机开发实现了传感器数据采集、运动部件的控制输出、上位机软件的数据上传和接收;3D建模及打印技术实现了非标零部件及机器外壳的制作,以低成本成功制作出样机;样机通过质控仪检测,流量值误差范围为±15%,气道压力值误差范围为±[2%FS(满量程)+4%×实际读数],样机参数精度满足JJF1234-2018《呼吸机校准规范》要求。结论野火骄阳32单片机开发板和3D建模及打印技术的应用,以低成本实现了样机制作,能够为专利的商业转化提供重要参考,为医工专利转化提供了一种新的思路。

6000t自由锻造水压机改油压机关键技术研究

本文提出了6000t自由锻造水压机升级改造的必要性,介绍了6000t自由锻造水压机升级改造的路径及改造后主要参数,阐述了控制系统升级改造方案及其关键技术。