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INVESTIGATION OF VORTEX SHEDDING INDUCED HYDRODYNAMIC VIBRATION IN VORTEX STREET FLOWMETER

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Chinese Journal of Mechanical Engineering 2001年第4期14卷 310-313页

作者： fu xin,Xu Bing,yang huayong (state key laboratory of fluid power transmission and control,zhejiang university) 浙江大学流体传动及控制国家重点实验室浙江

Vortex street flowmeter has been used in steady flow measurement for about three decades The benefits of this type of flowmeter include high accuracy,good linearty,wide measuring range,and excellent reliability However,in unsteady flow measurement,the pressure disturbance as well as the noise from the system or surrounding can reduce the signal to noise ratio of the flowmeter seriously Aimed to use vortex street flowmeters in unsteady flow measurement,the characteristics of the vortex shedding induced hydrodynamic vibration around the prism bluff body in a vortex street flowmeter are investigated numerically and by expriments The results show that the hydrodynamic vibrations with 180° phase shift occur at the axisymmetric points of the channel around the bluff body The most intense vibration occurs at the points on the lateral faces close to the base of the prism The results provide therefore a useful reference for developing an anti interference vortex flowmeter using the different ial sensing technique.

关键词： Vortex street flowmeter Vortex shedding induced hydrodynamic vibration Unsteady flow measurement Anti-interference performance

SIMULATION OF fluid FLOW IN CHANNEL OF A NOVEL HYDRAULIC SHOCK GENERATOR

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Chinese Journal of Mechanical Engineering 2000年第4期13卷 258-262页

作者： fu xinyang huayong (state key laboratory of fluid power transmission and control, zhejiang university) 浙江大学流体传动及控制国家重点实验室浙江杭州

In order to improve the engineering performance of a novel hydraulic shock generator, the fluid flow inside its complex passages is numerically investigated. The effects of the inlet flow velocity upon the turbulence intensity of the jet flow are analyzed. The calculated pressure loss is experimentally verified with the consideration of temperature determined viscosity shifting. The results are used as the reference in the further development of the hydraulic shock generator

关键词： Shock generator Numerical simulation Jet flow Turbulence

SIMULATION AND EXPERIMENTAL STUDY ON BUBBLY FLOW INSIDE THROTTLING GROOVE

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SIMULATION AND EXPERIMENTAL STUDY ON BUBBLY FLOW INSIDE THRO...

Flow-restricted Etching Method on Isotropic Substrates and Its Mechanism

第七届海内外青年设计与制造科学会议

作者： fu xin and Du Xuewen The state key laboratory of fluid power transmission and control zhejiang university China

＜正＞The relationship between pressure distribution and cavitation （noise） inside throttling groove has been investigated by numerical simulation and experimental method. A valve pocket with several transducers was performed to detect the pressure distributions inside the valve chamber, and the results fit quite well with the CFD analysis. High-speed imaging techniques have been employed to investigate the cavitation mechanisms, in particular bubble inception and cluster formation near the throttling groove. A spectrum analyser was used to measure the sound pressure level of noise generated by the bubble flow. It is found that pressure distributions inside the groove are sensitive to the valve port configuration and back pressure, which substantially determines the bubble size and number passing through the valve notches and the sound pressure level of noise induced by collapsing bubbles.

关键词： Pressure Distribution CFD Valve Cavitation Noise

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Chinese Journal of Mechanical Engineering 2010年第5期23卷 560-567页

作者： XIE Haibo ZHENG Yi FAN Yurun fu xin yang huayong The state key Lab of fluid power transmission and control Zhejiang University Hangzhou 310027 China

With the development of analytical instrumentation to minimization,integration and automation,the microfluidic chips,which are more integrated,complex and diversified,have been applied widely on the manufacturing of analytical ***,the present photolithography-based microfabrication technology,which is only able to pattern microchannels with simple inside structures,can not follow the rapid development of *** solving the problem,a fabrication method based on the restricting effect of laminar flow is proposed for the micro etching on isotropic *** were conducted inside glass-based microchannels,in which certain etchant was used to form complicated *** flow parameters＇ effects on the aspect ratio,side wall profile and etching rate were revealed by the *** experimental results reveal that the topography of micro structures patterned with the restricted flow etching method is mainly determined by the flowrates of separator and *** computational fluid dynamics（CFD） model on the interface between multiple streams was established for the etching process,and analysis on the causes of various micro topographies was conducted based on the CFD simulation *** experimental data consisted with the simulation results very *** investigation depicted in this paper indicate that the flow restricted etching method provides sufficient references for the research and understanding on the mass transport at the liquid-liquid surface in the microchannel and can be used to pattern complex micro structures with high aspect ratios,meantime,it greatly enriches the microfabrication technology for microfluidic chips.

关键词： microfluidics etching computational fluid dynamics(CFD) laminar

Design and testing of micro fluidic chemical analysis chip integrated with micro valveless pump

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Science China(Technological Sciences) 2005年第3期48卷 326-337页

作者： fu xin XIE Haibo yang huayong JIA Zhijian FANG Qun state key laboratory of fluid power transmission and control Zhejiang UniversityHangzhou 310027China State Key Laboratory of Fluid Power Transmission and ControlZhejiang UniversityHangzhou 310027China State Key Laboratory of Fluid Power Transmission and ControlZhejiang UniversityHangzhou 310027China Institute of Microanalytical SystemsZhejiang UniversityHangzhou 310028China Institute of Microanalytical SystemsZhejiang UniversityHangzhou 310028China

A new structure and working principle of the chip integrated with micro valveless pump for capillary electrophoresis was proposed in this paper. The micro valveless pump with plane structure has advantages of simple structure, and the process technology is compatible with existing micro chips for capillary electrophoresis. Based upon the mathematical model, simulation study of micro pump was carried out to investigate the influence of structural parameters on flow characteristics, and the performance of the integrated micro pump was also tested with different control parameters. The simulation results agree with the experimental results. Three samples, which are amino acid, fluorescein and buffer solution, have been examined with this chip. The results of the primary experiments showed that the micro valveless pump was promising in the integration and automatization of miniature integrated fluidic systems.

关键词： MEMS,micro valveless pump,micro fluidic chip,CFD,capillary electrophoresis.

SIMULATION AND EXPERIMENT OF BUBBLY FLOW INSIDE THROTTLING GROOVE

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Chinese Journal of Mechanical Engineering 2007年第5期20卷 37-41页

作者： fu xin DU Xuewen ZOU Jun yang huayong JI Hong state key laboratory of fluid power transmission and control Zhejiang University Hangzhou 310027 China School of fluid power and control Engineering Lanzhou University of Technology Lanzhou 730050. China

The relationship between pressure distribution and cavitation （noise） inside throttling groove is investigated by numerical simulation and experimental method. A valve pocket with several transducers is performed to detect the pressure distributions inside the valve chamber, and the results fit quite well with the computational fluid dynamics（CFD） analysis. High-speed imaging techniques are employed to investigate the cavitation mechanisms, in particular bubble inception and cluster formation near the throttling groove. A spectrum analyzer is used to measure the sound pressure level of noise generated by the bubble flow. It is found that the pressure distributions inside the groove are sensitive to the valve port configuration and back pressure. The pressure distribution determines the bubble size and number passing through the valve grooves and the sound pressure level of noise induced by collapsing bubbles. The inlet pressure mainly affects the saturation degree of bubbly flow inside the groove and the intensity of sound nressure level accordingly.

关键词： Pressure distribution Throuling groove Valve Cavitation Noise

Study on hydrodynamic vibration in fluidic flowmeter

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Journal of zhejiang university-Science A(Applied Physics & Engineering) 2007年第9期8卷 1422-1428页

作者： WANG Chi-yu ZOU Jun fu xin yang Hua-yong Institute state key laboratory of fluid power transmission amt control Zhejiang University Hangzhou 310027 China

The characteristics of the fluidic flowmeter,which is a combination of impinged concave wall and bistable fluid amplifier,is investigated by experimental studies and numerical simulations. The numerical approaches are utilized to examine the time dependent flow field and pressure field inside the proposed flowmeter. The effect of varying structural parameters on flow characteristics of the proposed fluidic flowmeter is investigated by computational simulations for the optimization. Both the simulation and experimental results disclose that the hydrodynamic vibration,with the same intensity,frequency and 180° phase shift,occurs at axisymmetric points in the feedback channel of the fluidic flowmeter. Using the structural combination of impinged concave wall and bistable fluid amplifier and differential signal processing technique,a novel fluidic flowmeter with excellent immunity and improved sensibility is developed.

关键词： Flowmeter fluidic Hydrodynamic vibration Coanda effect

Measurement of the thermal transport properties of dielectric thin films using the micro-Raman method

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Journal of zhejiang university-Science A(Applied Physics & Engineering) 2009年第1期10卷 7-16页

作者： Shuo HUANG Xiao-dong RUAN xin fu Hua-yong yang state key laboratory of fluid power transmission and control Zhejiang University Hangzhou 31002 7 China

The micro-Raman method is a non-contact and non-destructive method for thermal conductivity *** reduce the measurement error induced by the poor fit of the basic equation of the original micro-Raman method,we developed a new basic equation for the heat source of a Gaussian laser *** on the new basic equation,an analytical heat transfer model has been built to extend the original micro-Raman method to thin films with submicrometer-or nanometer-scale ***-periments were performed to measure the thermal conductivity of dielectric thin films with submicrometer-or nanometer-scale *** thermal resistance of the interface between dielectric thin films and their silicon substrate was also *** obtained thermal conductivity of silicon dioxide film is 1.23W/(m.K),and the interface thermal resistance between silicon dioxide film and substrate is 2.35×10-8m2.K/*** thermal conductivity and interface thermal resistance of silicon nitride film are 1.07W/(m.K)and 3.69×10-8m2.K/W,*** experimental results are consistent with reported data.

关键词： Thermal conductivity Dielectric thin films Submicrometer- or nanometer-scale Porous silicon Thermal effect micro-systems (TEMS)

Optimal design of Stewart platforms based on expanding the control bandwidth while considering the hydraulic system design

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Journal of zhejiang university-Science A(Applied Physics & Engineering) 2009年第1期10卷 22-30页

作者： Wei WANG Hua-yong yang Jun ZOU Xiao-dong RUAN xin fu state key laboratory of fluid power transmission and control zhejiang university Hangzhou 310027 China

We proposed an optimal design method to expand the bandwidth for the control of large hydraulic Stewart *** method is based on generalized natural frequency and takes hydraulic oil into consideration.A Lagrangian formulation which considers the whole leg inertia is presented to obtain the accurate equivalent mass *** the model,the effect of leg inertia and the influence of design parameters on the generalized natural frequency are ***,numerical examples are presented to validate and confirm the efficiency of the mathematical *** results show that the leg inertia,especially the piston part plays an important role in the *** optimum diameter ratio of the base to the moving platform is between 2 and 3,and the optimum joint angle ratio of the base to the moving platform is about *** smaller joint angles and a longer leg stroke are favorable for raising system *** system oil should be preprocessed for large platforms with a requirement for good dynamic performance.

关键词： Large Gough-Stewart platform Optimal design control bandwidth Leg inertia Generalized natural frequency