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Experimental Study on the flow characteristics of a Plate with a Mechanically Choked Orifice

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Fluid Dynamics & Materials Processing 2021年第1期17卷 97-107页

作者： Ming Liu Xingkai Zhang Dong Wang State Key Laboratory of Multiphase flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Petroleum Engineering Technology Research Institute of Shengli Oilfield Company SINOPECDongying257000China Shandong Key Laboratory of Heavy Oil Production Technology Shengli Oilfield CompanySINOPECDongying257000China Petroleum Engineering College Yangtze UniversityWuhan430100China

The mechanically choked orifice plate (MCOP) is a new type of device for flow control by which choking conditionsfor incompressible fluids can be obtained with relatively small pressure losses. Given the lack of relevant results anddata in the literature, in the present study, we concentrate on the experimental determination of the flow coefficientfor the annular orifice, the pressure distribution in the MCOP, and the characteristics of the choked flow itself. Asconfirmed by the experimental results, the Reynolds number, the orifice plate thickness, the plug taper, and theeccentricity have an obvious influence on the aforementioned flow coefficient. The pressure drop in the MCOPis mainly generated near the orifice plate, and the pressure upstream of the orifice plate is slightly reduced in theflow direction, while the pressure downstream of the orifice plate displays a recovery trend. The choked flow rateof the MCOP can be adjusted by replacing the spring with a maximum flow control deviation of 4.91%.

关键词： Mechanical choked orifice plate flow control flow coefficient flow characteristics

Analysis of Gas-Solid flow characteristics in a Spouted Fluidized Bed Dryer by Means of Computational Particle Fluid Dynamics

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Fluid Dynamics & Materials Processing 2020年第4期16卷 813-826页

作者： Hongming Zhou Haozheng Gao Zheng Fang Jiangxin Yang Mingge Wu College of Mechanical and Electrical Engineering Wenzhou UniversityWenzhou325035China Zhejiang Canaan Technology Co. Ltd.Wenzhou325000China School of Mechanical Engineering Zhejiang UniversityHangzhou310027China

In order to grasp the particle flow characteristics and energy consumption of industrial fluidized spouted beds,we conduct numerical simulations on the basis of a Computational Particle Fluid Dynamics(CPFD)approach.In particular,the traction model of Wen-Yu-Ergun is used and different inlet conditions are considered.Using a low-speed fluidizing gas,the flow state of the particles is better and the amount of particles accumulated at the bottom of the bed wall becomes smaller.For the same air intake,the energy loss of a circular nozzle is larger than that of a square nozzle.

关键词： Spouted fluidized bed CPFD flow characteristics numerical simulation

Experimental Investigation on flow characteristics at Leeside of Suspended Flexible Curtain for Sedimentation Enhancement

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China Ocean Engineering 2009年第3期23卷 565-576页

作者：李艳红喻国良 School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University

A new patent registered device- suspended flexible curtain （SFC） for sedimentation enhancement is proposed in this paper, which consists of two parts： a light-weight curtain with sediment-passing windows and a heavy pillar for the device stability. The mechanism of trapping nearbed sediment by the SFC is such that a primary and a secondary circulations with horizontal hubs would be formed at the leeside when it is placed on beds in running flow; the velocities within the sediment-passing windows are locally accelerated, the nearbed sediments would be brought by the flow through the windows, and then settled down within the primary circulation zone. Experimental tests on hydraulic characteristics are conducted in a laboratory flume with rigid bed. It is found that the dimensions of the curtain and the sediment-passing windows determine the characteristics of the primary and the secondary circulations. The intensity of the primary and the secondary circulations is dominated by the size of the sediment-passing window. Whether the secondary circulation would contact the bed or not depends on the level of the sediment-passing window. The length and the height of the primary circulation zone demonstrate quasi linear relationships with the effective height of the SFC. And the tests on sandy bed flume show that the sediment deposition happens just in the primary circulation zone.

关键词： flow characteristics laboratory flume suspended flexible curtain sediment-passing window trapping sediment

EXPERIMENTAL STUDY OF EFFECTS OF OPERATING CONDITIONS ON THE flow characteristics OF WATER HYDRAULIC THROTTLE

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Chinese Journal of Mechanical Engineering 2004年第3期17卷 450-453页

作者： LiuYinshui NieSonglin ZhuYuquan HeXiaofeng LiZhuangyun SchoolofMechanicalScienceandEngineering HuazhongUniversityofScienceandTechnologyWuhan430074China

Experimental investigations are made on the effects of operating conditionson the flow characteristics of throttle when tap water is used as the working media. The researchedthrottles include cone poppet valve, ball valve, disc valve and dumping orifice. Operating conditionincludes poppet lift, working media, back pressure, medium temperature, etc. Because the vapourouspressure of water is much higher than that of oil, cavitation is easier to occur in water hydraulicelements and systems, so the effects of operating conditions on the cavitation characteristics ofthrottle are also researched.

关键词： Water hydraulics flow characteristics Hydraulic throttle Operatingcondition Cavitation

characteristics of the flow and Sediment in the Inner Rivers' Broad-shallow Shifting Reach

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四川大学学报（工程科学版） 2005年第S1期37卷 93-97页

作者： Yang, Shengfa Zhou, Huajun Fang, Duo State Key Lab. of Hydraulics Sichuan Univ. Chengdu 610065 China

Rivers are classified into two types.One is the outer river which flows into ocean and the other is the inner river which does not flow into the ocean but into desert or lake.The inner rivers are the erosive rivers that have been seldom studied so far.Based on the field survey data,the analysis on the characteristics of the flow and sediment in the inner rivers' broad-shallow shifting (IRBS) reach.The IRBS reach often bears such the properties as:high gradient bed,usually 10‰or greater;small flow dischar...

关键词： the IRBS reach watershed features flow characteristics sedment transport

EXPERIMENTAL INVESTIGATIONS OF CAVITATION EFFECTS ON flow characteristics OF SMALL ORIFICES AND VALVES IN WATER HYDRAULICS

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 380-384页

作者： Zhu Bihai Zhang Tiehua Huang Yan Li Zhuangyun School of Mechanical Engineering, Huazhong University of Science and Technology,Wuhan 430074, China School of Mechanical Engineering Huazhong University of Science and Technology Wuhan 430074

The flow characteristics and cavitation effects of water passing throughsmall sharp-edged cylindrical orifices and valves of different shapes in water hydraulics areinvestigated. The test results using orifices with different aspect ratios and different diametersshow that the flow coefficients in the case of non-cavitating flow are larger than that of flow inthe case of cavitation occurrence. The flow coefficients of flow with cavitation initially decreaseas Reynolds number increases and ultimately tend to be of constant values close to contractioncoefficient. Large aspect ratio has an effect of suppressing cavitation. The experimental resultsabout disc valves illustrate that the valves with sharp edge at large opening are less affected bycavitation than that at small opening. Throttle with triangle notch has better anti-cavitationability than that with square notch. The flowrate of the throttle with square notch is significantlyaffected by the flow direction or the flow passage shape.

关键词： cavitation flow characteristics small orifices water hydraulic valves

Aerothermodynamic Design and flow characteristics for a S-CO_(2) Radial Inflow Turbine

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Mechanical Engineering Science 2021年第2期3卷 17-24页

作者： Lehao HU Yu JIANG Qinghua DENG Zhuobin ZHAO Jun LI Zhenping FENG Institute of Turbomachinery Xi'an Jiaotong UniversityXi'anChina Collaboration Innovation Center of Advanced Aeroengine Beihang UniversityBeijing 100191China

In this paper,a radial inflow turbine is designed for the 150 kW S-CO_(2) Brayton cycle system,and flow characteristics and off-design performances are analyzed.The design results are accurate and high performances can be achieved for the S-CO_(2) power system,and the total-static efficiency of 86%and net output power about 285.2 kW can meet the design requirements of S-CO_(2) cycle system.The results of the flow characteristics show the streamlines of radial inflow turbine distribute uniformly,and the vortexes generated at the shroud of the blade suction surface have little influence on the turbine performances.The off-design performances show the total-static efficiency remains above 80%in the pressure ratio range of 1.6~2.9,and the output power and mass flow rate increase with the pressure ratio increasing.It is indicated that the designed turbine has excellent off-design performances and can meet the operation requirements.The study results can provide guidance for S-CO_(2) radial inflow turbine design and operation.

关键词： supercritical carbon dioxide radial inflow turbine flow characteristics off-design performances

Numerical Investigation of flow characteristics in the Obstructed Realistic Human Upper Airway

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Numerical Investigation of Flow Characteristics in the Obstr...

Gas Leakage Detection and Pressure Difference Identification by Asymmetric Differential Pressure Method

第九届全国流体力学学术会议

作者： Xingli Liu Weiwei Yan College of Metrology and Measurement Engineering China Jiliang University

In this study,the flow characteristics in the realistic human upper airway(HUA) with obstruction that resulted from pharyngeal collapse were numerically investigated.The 3-D anatomically accurate HUA model was reconstructed from CT-scan images of a Chinese male patient(38 years,BMI 25.7).The computational fluid dynamics(CFD) with the large eddy simulation(LES) method was applied to simulate the inspiratory and expiratory airflows dynamics in the HUA model.Besides,the laser Doppler anemometry(LDA) technique was simultaneously adopted to measure the airflow fields in the HUA model for the purpose of testifying the reliability of LES approach.In the simulations,the representative respiration intensities of 16.8 L/min(slight breathing),30 L/min(moderate breathing),and 60 L/min(severe breathing) were conducted under continuous inspiration and expiration conditions.The airflow velocity field and static pressure field were obtained and discussed in detail.The results indicated the air in the HUA model experiences unsteady transitional/turbulent flow under low Reynolds number.The airflow fields occurs forceful injection phenomenon due to the narrowing of pharynx caused by the respiratory illness during both inspiration and expiration processes.There also exists strong flow separation and back flow inside obstructed HUA owing to the vigorous jet flow effect in the pharynx.The present results would provide theoretical guidance for the treatment of obstructive respiratory disease.

关键词： upper airway flow characteristics circular breathing obstructive sleep apnea large eddy simulation

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Chinese Journal of Mechanical Engineering 2022年第2期35卷 150-158页

作者： Yan Shi Jiaqi Chang Yixuan Wang Xuelin Zhao Qingzhen Zhang Liman Yang School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Department of Musculoskeletal tumor The Fourth Medical Center of PLA General HospitalBeijing 100089China Senior Department of Orthopedics The Fourth Medical Center of PLA General HospitalBeijing 100089China

Currently,the measurement methods for pneumatic system leakage include bubbling,ultrasonic,and pressure detection methods.These methods are sensitive to high-precision sensors,long detection times,and stable external environments.The traditional differential pressure method involves severe differential pressure fluctuations caused by environmental pressure fluctuations or electromagnetic noise interference of sensors,leading to inaccurate detection.In this paper,a differential pressure fitting method for an asymmetric differential pressure cylinder is proposed.It overcomes the limitation of the detection efficiency caused by the asynchronous temperature recovery of the two chambers in the asymmetric differential pressure method and uses the differential pressure substitution equation to replace the differential calculation of the differential pressure.The improved differential pressure method proposes an innovation based on the detection principle and calculation method.Additionally,the influence of the parameters in the differential pressure substitution equation on the leakage calculation results was simulated,and the specific physical significance of the parameters of the differential pressure substitution equation was explained.The experiments verified the fitting effect and proved the accuracy of this method.Compared with the traditional differential pressure method,the maximum leakage deviation of inhibition was 0.5 L/min.Therefore,this method can be used to detect leaks in air tanks.

关键词： Leakage detection System identification Asymmetric tank Pneumatics Measurement flow characteristics