Directional Pumping Performance of an Electrostatic Checkerboard Microvalve

2006 ◽  
Author(s):  
Hanseup Kim ◽  
Aaron A. Astle ◽  
Luis P. Bernal ◽  
Khalil Najafi ◽  
Peter D. Washabaugh
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Maximum Flow ◽  
Pressure Differential ◽  
Oscillatory Motion ◽  
Sinusoidal Signal ◽  
Maximum Pressure ◽  
Experimental Characterization ◽  
Gas Pumping

This paper reports experimental characterization of directional gas pumping generated by MEMS-fabricated checkerboard-type electrostatic microvalves. It is found that the oscillatory motion of the checkerboard microvalve membrane provides both the pumping and valve functions of a pump, namely: 1) to cause the volume displacement and, thus, compression and transfer of gas, and 2) to direct gas flow in one direction by closing and opening air paths in the proper sequence. Here, we describe the microvalve-only design, and report the pumping performance producing a maximum flow rate of 1.8 sccm and a maximum pressure differential of 3.0 kPa for five microvalves driven simultaneously with a sinusoidal signal of ± 100V amplitude at 5.5 kHz.

Effect of shielding gas flow rate on arc behaviors in GMAW with single cable-typed wire

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040059
Author(s):  
Qingxian Hu ◽  
Lei Zhang ◽  
Juan Pu ◽  
Caichen Zhu
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Gas Metal Arc Welding ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
Maximum Pressure ◽  
Arc Plasma ◽  
Shielding Gas ◽  
Gas Flow Rate

A three-dimensional numerical model of arc in gas metal arc welding (GMAW) with single cable-typed wire was established based on the theory of arc physics. The influences of different shielding gas flow rates on the features of temperature field, velocity field and pressure field were investigated. The results showed that the maximum velocity of arc plasma along radial direction and the arc pressure on the surface of workpieces were increased obviously with the increase of the shielding gas flow rate, while the arc temperature was changed little. This phenomenon was mainly attributed to the increasing collisions between arc plasmas and the self-rotation action of cable-typed wires. The arc temperature at the tip of the cable-typed wire reached the maximum. The maximum flow velocity of arc plasma was located at the tip of wire (2–8 mm). The arc pressures in the central axis reached the maximum pressure. The simulation results were in agreement with the experimental results.

Experimental Characterization of Aerosol Production, Transport, Vaporization, and Atomization Systems. Part II: Factors Controlling Aerosol Size Distributions Produced

1985 ◽  
Vol 39 (6) ◽  
pp. 920-925 ◽  
Author(s):  
R. K. Skogerboe ◽  
S. J. Freeland
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Cross Flow ◽  
Size Distributions ◽  
Experimental Characterization ◽  
Gas Flow Rate ◽  
Mean Size ◽  
The Mean ◽  
Model Equations

The effects of nebulization conditions on the size characteristics of the aqueous aerosol produced have been investigated for a cross-flow nebulizer. It is shown that the nebulizer gas flow rate does not affect the upper limit mean sizes of the aqueous droplets transported from the nebulization chamber but that the mean size of the analyte-containing aerosol itself is affected. Model equations are presented descriptive of the effects of gas flow rate and analyte concentrations on analyte aerosol size characteristics.

Experimental Characterization of Aerosol Production, Transport, Vaporization, and Atomization Systems. Part I: Factors Controlling Aspiration Rates

1985 ◽  
Vol 39 (6) ◽  
pp. 916-920 ◽  
Author(s):  
R. K. Skogerboe ◽  
S. J. Freeland
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Gas Flow ◽  
Present Knowledge ◽  
Experimental Characterization ◽  
Gas Flow Rate ◽  
Factors Affecting ◽  
Simple Linear Equation ◽  
The Relationship

This paper describes the results of the first stage of an investigation designed to extend present knowledge of the factors affecting aerosol production, transport, vaporization, and atomization in analytical spectroscopy systems. It focuses on factors controlling aspiration of aqueous solutions. The results demonstrate that the effect of gas flow on the pressure drop induced at the tip of the solution draw tube can be described by a simple linear equation; that the relationship between gas flow rate and solution nebulization rate can also be modelled by a simple equation; and that these relationships are not adequately represented by the Hagen-Poiseulle equation, as is often claimed.

Theoretical and Experimental Performance of a High Frequency Micropump

2005 ◽  
Author(s):  
Aaron Astle ◽  
Luis P. Bernal ◽  
Hanseup Kim ◽  
Khalil Najafi ◽  
Peter D. Washabaugh
Keyword(s):  
High Frequency ◽  
Maximum Flow ◽  
Maximum Pressure ◽  
Experimental Characterization ◽  
Chemical Monitoring ◽  
Multi Stage ◽  
Micro Systems ◽  
The University ◽  
Theoretical Analyses

This paper details theoretical analyses and experimental characterization of high-frequency multi-stage micro pumps. The MEMS-fabricated micro pumps have been developed for use in a highly-integrated chemical monitoring system under development at the University of Michigan’s Wireless Integrated Micro-Systems center. Tests are reported on a 20x meso-scale 2-stage pump developed to validate the theoretical analyses. Detailed comparisons of the pump performance and unsteady pressure traces show that the theoretical analyses capture the main features of the flow in the pump. A MEMS-fabricated device has been developed and tested. The use of theoretical analyses for the design of the pump is described. This device produces A maximum flow of 1.1 ccm and a maximum pressure of 879 Pa.

Characterization of a Radiantly Driven Multistage Knudsen Compressor

2003 ◽  
Author(s):  
M. Young ◽  
Y. L. Han ◽  
E. P. Muntz ◽  
G. Shiflett
Keyword(s):  
Steady State ◽  
Atmospheric Pressure ◽  
Maximum Flow ◽  
Performance Model ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Flow Rates ◽  
Micro Scale ◽  
Knudsen Compressors

Knudsen Compressors are meso/micro scale gas compressors/pumps based on thermal transpiration or thermal creep. The design of radiantly driven Knudsen Compressors is discussed, along with a model that was developed to understand their performance. Experimental pumping performances for Knudsen Compressors with one, two, five, and fifteen stage, radiantly driven cascades are also discussed. Temperature measurements across the transpiration membranes, for various pressures of Nitrogen, were obtained and compared to those predicted by the performance model. The results agree with the model to within 15% consistently under predicting the measured hot side temperature of the transpiration membrane. The pump-down curves, steady-state maximum pressure differences, and maximum flow rates produced by a single stage Knudsen Compressor were obtained. A variety of configurations were studied at pressures from 500 mTorr to atmospheric pressure. The experimental results agreed with the performance model’s predictions to within 20%.

Simulation and Experimental Study of a Porous Electroosmotic Pump

2011 ◽  
Vol 483 ◽  
pp. 320-326 ◽  
Author(s):  
Zhou Ling ◽  
Tao Yang ◽  
Fan Chao Meng ◽  
Lin Yi ◽  
Xiang Xian Zhang
Keyword(s):  
Porous Media ◽  
Flow Rate ◽  
Pore Diameter ◽  
Maximum Flow ◽  
Joule Heat ◽  
Maximum Pressure ◽  
Electrical Field ◽  
Electroosmotic Pump ◽  
The Mathematical Model ◽  
Truncated Gaussian

Aiming at the coupling problems of electrical field and flow field in porous media microchannels, the mathematical model of electroosmotic(EO) flow is built. For a single microchannel, the influence of voltage on velocity and joule heat is analyzed by using CoventorWare. Numerical analysis shows that the velocity is proportional to the voltage and the joule heat is small and negligible. For the porous media, the flow rate is investigated by truncated Gaussian distribution of pore diameter. The electroosmotic microporous pump is fabricated, and the experimental results indicate that the maximum flow rate of porous media micropump is 16.89ml/min and the maximum pressure is 120.1kPa.

scholarly journals Simulation of a Chain of Collapsible Contracting Lymphangions With Progressive Valve Closure

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
C. D. Bertram ◽  
C. Macaskill ◽  
J. E. Moore
Keyword(s):  
Flow Rate ◽  
Flow Direction ◽  
Maximum Flow ◽  
Transmural Pressure ◽  
Maximum Flow Rate ◽  
Smooth Transition ◽  
Maximum Pressure ◽  
Mean Flow ◽  
Forward Flow ◽  
In Series

The aim of this investigation was to achieve the first step toward a comprehensive model of the lymphatic system. A numerical model has been constructed of a lymphatic vessel, consisting of a short series chain of contractile segments (lymphangions) and of intersegmental valves. The changing diameter of a segment governs the difference between the flows through inlet and outlet valves and is itself governed by a balance between transmural pressure and passive and active wall properties. The compliance of segments is maximal at intermediate diameters and decreases when the segments are subject to greatly positive or negative transmural pressure. Fluid flow is the result of time-varying active contraction causing diameter to reduce and is limited by segmental viscous and valvular resistance. The valves effect a smooth transition from low forward-flow resistance to high backflow resistance. Contraction occurs sequentially in successive lymphangions in the forward-flow direction. The behavior of chains of one to five lymphangions was investigated by means of pump function curves, with variation of valve opening parameters, maximum contractility, lymphangion size gradation, number of lymphangions, and phase delay between adjacent lymphangion contractions. The model was reasonably robust numerically, with mean flow-rate generally reducing as adverse pressure was increased. Sequential contraction was found to be much more efficient than synchronized contraction. At the highest adverse pressures, pumping failed by one of two mechanisms, depending on parameter settings: either mean leakback flow exceeded forward pumping or contraction failed to open the lymphangion outlet valve. Maximum pressure and maximum flow-rate were both sensitive to the contractile state; maximum pressure was also determined by the number of lymphangions in series. Maximum flow-rate was highly sensitive to the transmural pressure experienced by the most upstream lymphangions, suggesting that many feeding lymphatics would be needed to supply one downstream lymphangion chain pumping at optimal transmural pressure.

Design and Analysis of a Thin Film Permanent Magnet Actuated Micro Pump

2013 ◽  
Vol 7 (2) ◽  
pp. 196-204 ◽  
Author(s):  
Chao Zhi ◽  
◽  
Tadahiko Shinshi ◽  
Minoru Uehara ◽  
Keyword(s):  
Thin Film ◽  
Permanent Magnet ◽  
Flow Rate ◽  
Maximum Flow ◽  
High Flow ◽  
Deformation Analysis ◽  
Maximum Pressure ◽  
Large Deformation Analysis ◽  
Micro Pump ◽  
Displacement Measurements

In this paper we present the design, analysis and an experimental evaluation of a micro pump utilizing a 20 µm thick, 3 mm diameter Thin Film Permanent Magnet (TFPM). The pump includes an electromagnet that uses a magnetic closed circuit. The design of the electromagnet was optimized and was theoretically explained. A PolyDiMethylSiloxane (PDMS) diaphragm with a thickness of approximately 80 µm was used in the pump. The electromagnetic force on the diaphragmwas calculated using a finite elementmethod. Large deformation analysis was used to calculate the displacement of the diaphragm. The force and displacement measurements agreed well with those calculated by simulation. The performance of the fabricated pump was also evaluated. During pumping, the displacement of the diaphragm reached 500 µm, which is the same as the height of the chamber. Furthermore, because of the large displacement, the pump is bubble tolerant and self-priming. A maximum flow rate of 50 µL/min and a maximum pressure of 110 Pa were achieved. A square wave input signal was demonstrated to be more effective than a sinusoidal signal in generating a high flow rate.

A miniaturized gas flow energy harvester using diamagnetically stabilized levitation

2020 ◽  
Vol 92 (1) ◽  
pp. 10903
Author(s):  
Kun Zhang ◽  
Qi Gong ◽  
Xia Li ◽  
Yufeng Su ◽  
Zhiyong Duan
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Energy Harvester ◽  
Incident Angle ◽  
Pyrolytic Graphite ◽  
Maximum Flow ◽  
Induced Voltage ◽  
Flow Energy ◽  
The Stability ◽  
Maximum Voltage

In this paper, a miniaturized energy harvester is presented to scavenge gas flow energy. A magnet rotor with three teeth evenly distributed on the edge was introduced into the energy harvester, and it is frictionlessly levitated between two highly oriented pyrolytic graphite (HOPG) sheets. The energy harvester is designed to operate at a single stable equilibrium, so as to improve the stability of the rotor. The optimal incident angle of the gas flow was determined to be 83°. On the basis of the optimal angle, two different configurations of the energy harvester were proposed. Configuration A includes one nozzle, while Configuration B has two centrosymmetric nozzles. The maximum flow rate that enables Configurations A to work stably is limited, which can be increased by thickening the magnet rotor. The maximum voltage of configuration A was 0.28 V at a flow rate of 1500 sccm for the 4.5 mm thick rotor. Configuration B can run stably at any flow rate bigger than 250 sccm and the induced voltage increases with the driving flow rate. At the flow rate of 3000 sccm, the energy harvester of Configuration B can generate a maximum voltage of 3 V and light up tens of light-emitting-diodes (LEDs).

Comprehensive Fall Velocity Study on Continuous Flow Plungers

2021 ◽  
pp. 1-20
Author(s):  
Ozan Sayman ◽  
Eduardo Pereyra ◽  
Cem Sarica
Keyword(s):  
Drag Coefficient ◽  
Flow Rate ◽  
Continuous Flow ◽  
Gas Flow ◽  
Flow Simulation ◽  
Maximum Flow ◽  
Wall Effect ◽  
Liquid Holdup ◽  
Fall Velocity ◽  
Influential Parameters

Summary The objective of this study is the experimental and theoretical investigation of the fall mechanics of continuous flow plungers. Fall velocity of the two-piece plungers with different sleeve and ball combinations and bypass plungers are examined in both static and dynamic conditions to develop a drag coefficient relationship. The dimensionless analysis conducted included the wall effect, inclination, and the liquid holdup correction of the fall stage. A fall model is developed to estimate fall velocities of the ball, sleeve, and bypass plungers. Sensitivity analysis is performed to reveal influential parameters to the fall velocity of continuous flow plungers. In a static facility, four sleeves with different height, weight, and outer diameter (OD); three balls made with different materials; and a bypass plunger are tested in four different mediums. The wall effect on the settling velocity is defined, and it is used to validate the ball drag coefficient results obtained from the experimental setup. Two-phase flow experiments were conducted by injecting gas into the static liquid column, and the liquid holdup effect on the drag coefficient is observed. Experiments in a dynamic facility are used for liquid holdup and deviation corrections. The fall model is developed to estimate fall velocities of the continuous flow plungers against the flow. Dimensionless parameters obtained in the experiments are combined with multiphase flow simulation to estimate the fall velocity of plungers in the field scale. Reference drag coefficient values of plungers are obtained for respective Reynolds number values. Experimental wall effect, liquid holdup, and inclination corrections are provided. The fall model results for separation time, fall velocity, total fall duration, and maximum flow rate to fall against are estimated for different cases. Sensitivity analysis showed that the drag coefficient, the weight of plungers, pressure, and gas flow rate are the most influential parameters for the fall velocity of the plungers. Furthermore, the fall model revealed that plungers fall slowest at the wellhead conditions for the range of gas flow rates experienced in field conditions. Lower pressure at the wellhead had two opposing effects; namely, reduced gas density, thereby reducing the drag and gas expansion that increased the gas velocity, which in turn increased the drag. Estimating fall velocity of continuous flow plungers is crucial to optimize ball and sleeve separation time, plunger selection, and the gas injection rate for plunger-assisted gas lift (PAGL). The fall model provides maximum flow rate to fall against, which is defined as the upper operational boundary for continuous flow plungers. This study presents a new methodology to predict fall velocity using the drag coefficient vs. Reynolds number relationship, wall effect, liquid holdup, deviation corrections, and incorporating multiphase flow simulation.

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