The Experts below are selected from a list of 21672 Experts worldwide ranked by ideXlab platform
Lin Cheng - One of the best experts on this subject based on the ideXlab platform.
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experimental study on capillary Pumping Performance of porous wicks for loop heat pipe
Experimental Thermal and Fluid Science, 2010Co-Authors: Yong Zou, Lin ChengAbstract:The aim of this study is to investigate the capillary Pumping Performance of porous wick for the use of loop heat pipe by developing a method that studying the capillary Pumping amount real time changing curve which is recorded by electronic balance and computer. The porous wicks are prepared by powder metallurgy method using type 255 pure nickels as the material. The working fluids used in this study are water and acetone. The porous wicks investigated in this study include 3 with the same porosity and 4 with different porosities. The result shows that capillary Pumping amount changing curve of porous wick can be described with an exponential increase equation. The offset and the opposite of amplitude of the exponential increase equation are all equated to the total capillary Pumping amount of the porous wick. The time constant of the exponential increase equation is related to the capillary Pumping rate which indicates the comprehensive properties of capillary pressure and flow resistance of the system of porous wick and working fluid. Capillary Pumping rate is found to increase with the increasing porosities of the porous wicks. When porosities of the porous wicks are the same, those with tighter granules and straighter channels in the microstructures are found to have better capillary Pumping Performance.
Juan G Santiago - One of the best experts on this subject based on the ideXlab platform.
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porous glass electroosmotic pumps design and experiments
Joint International Conference on Information Sciences, 2003Co-Authors: Shuhuai Yao, David Hertzog, Shulin Zeng, James C Mikkelsen, Juan G SantiagoAbstract:An analytical model for electroosmotic flow rate, total pump current, and thermodynamic efficiency reported in a previous paper has been applied as a design guideline to fabricate porous-structure EO pumps. We have fabricated sintered-glass EO pumps that provide maximum flow rates and pressure capacities of 33 ml/min and 1.3 atm, respectively, at applied potential 100 V. These pumps are designed to be integrated with two-phase microchannel heat exchangers with load capacities of order 100 W and greater. Experiments were conducted with pumps of various geometries and using a relevant, practical range of working electrolyte ionic concentration. Characterization of the Pumping Performance are discussed in the terms of porosity, tortuosity, pore size, and the dependence of zeta potential on bulk ion density of the working solution. The effects of pressure and flow rate on pump current and thermodynamic efficiency are analyzed and compared to the model prediction. In particular, we explore the important tradeoff between increasing flow rate capacity and obtaining adequate thermodynamic efficiency. This research aims to demonstrate the Performance of EOF pump systems and to investigate optimal and practical pump designs. We also present a gas recombination device that makes possible the implementation of this Pumping technology into a closed-flow loop where electrolytic gases are converted into water and reclaimed by the system.
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porous glass electroosmotic pumps theory
Journal of Colloid and Interface Science, 2003Co-Authors: Shuhuai Yao, Juan G SantiagoAbstract:This paper presents an analytical study of electroosmotic (EO) pumps with porous Pumping structures. We have developed an analytical model to solve for electroosmotic flow rate, pump current, and thermodynamic efficiency as a function of pump pressure load for porous-structure EO pumps. The model uses a symmetric electrolyte approximation valid for the high-zeta-potential regime and numerically solves the Poisson-Boltzmann equation for charge distribution in the idealized pore geometry. Generalized scaling of Pumping Performance is discussed in the context of a parameterization that includes porosity, tortuosity, pore size, bulk ionic density, and the nonuniform conductivity distribution over charge layers. The model also incorporates an approximate ionic-strength-dependent zeta potential formulation.
Yong Zou - One of the best experts on this subject based on the ideXlab platform.
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experimental study on capillary Pumping Performance of porous wicks for loop heat pipe
Experimental Thermal and Fluid Science, 2010Co-Authors: Yong Zou, Lin ChengAbstract:The aim of this study is to investigate the capillary Pumping Performance of porous wick for the use of loop heat pipe by developing a method that studying the capillary Pumping amount real time changing curve which is recorded by electronic balance and computer. The porous wicks are prepared by powder metallurgy method using type 255 pure nickels as the material. The working fluids used in this study are water and acetone. The porous wicks investigated in this study include 3 with the same porosity and 4 with different porosities. The result shows that capillary Pumping amount changing curve of porous wick can be described with an exponential increase equation. The offset and the opposite of amplitude of the exponential increase equation are all equated to the total capillary Pumping amount of the porous wick. The time constant of the exponential increase equation is related to the capillary Pumping rate which indicates the comprehensive properties of capillary pressure and flow resistance of the system of porous wick and working fluid. Capillary Pumping rate is found to increase with the increasing porosities of the porous wicks. When porosities of the porous wicks are the same, those with tighter granules and straighter channels in the microstructures are found to have better capillary Pumping Performance.
Lin Gui - One of the best experts on this subject based on the ideXlab platform.
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development of a high flow rate 3 d electroosmotic flow pump
Micromachines, 2019Co-Authors: Renchang Zhang, Meng Gao, Zhongshan Deng, Lin GuiAbstract:A low voltage 3D parallel electroosmotic flow (EOF) pump composed of two electrode layers and a fluid layer is proposed in this work. The fluid layer contains twenty parallel fluid channels and is set at the middle of the two electrode layers. The distance between fluid and electrode channels was controlled to be under 45 μm, to reduce the driving voltage. Room temperature liquid metal was directly injected into the electrode channels by syringe to form non-contact electrodes. Deionized (DI) water with fluorescent particles was used to test the Pumping Performance of this EOF pump. According to the experimental results, a flow rate of 5.69 nL/min was reached at a driving voltage of 2 V. The size of this pump is small, and it shows a great potential for implanted applications. This structure could be easily expanded for more parallel fluid channels and larger flow rate.
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A Liquid-Metal Based Spiral Magnetohydrodynamic Micropump
MDPI AG, 2017Co-Authors: Xuyan Zhou, Meng Gao, Lin GuiAbstract:A liquid-metal based spiral magnetohydrodynamic (MHD) micropump is proposed in this work. The micropump was fabricated in a polydimethylsiloxane (PDMS)-glass hybrid microfluidic chip. This pump utilized two parallel liquid-metal-filled channels as electrodes to generate a parallel electrical field across the Pumping channel between the two electrodes. To prevent contact and cross contamination between the liquid metal in the electrode channel and the sample fluid in the Pumping channel, a PDMS gap was designed between the liquid metal and the sample fluid. To minimize the chip size, the parallel electrode and Pumping channels were designed in a spiral shape. To test Pumping Performance, NaCl aqueous solution containing fluorescent particles (0.5 μm in diameter) was filled into the Pumping channel as the working sample fluid. When a pair of identical magnets (0.4 T) was placed onto both top and bottom surfaces of the chip, the pump was able to drive the sample fluid at a flow velocity of 233.26 μm/s at 3000 V. The pump has no moving parts, and the electrodes are easily fabricated, making the pump suitable for miniaturization and integration into microfluidic systems
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a handy liquid metal based electroosmotic flow pump
Lab on a Chip, 2014Co-Authors: Meng Gao, Lin GuiAbstract:A room temperature liquid metal based electroosmotic flow (EOF) pump has been proposed in this work. This low-cost EOF pump is convenient for both fabrication and integration. It utilizes polydimethylsiloxane (PDMS) microchannels filled with the liquid-metal as non-contact pump electrodes. The electrode channels are fabricated symmetrically to both sides of the Pumping channel, having no contact with the Pumping channel. To test the Pumping Performance of the EOF pump, the mean flow velocities of the fluid (DI water) in the EOF pumps were experimentally measured by tracing the fluorescent microparticles in the flow. To provide guidance for designing a low voltage EOF pump, parametric studies on dimensions of the electrode and Pumping channels were performed in this work. According to the experimental results, the Pumping speed can reach 5.93 μm s−1 at a driving voltage of only 1.6 V, when the gap between the electrode and the Pumping channel is 20 μm. Injecting a room temperature liquid metal into microchannels can provide a simple, rapid, low-cost but accurately self-aligned way to fabricate microelectrodes for EOF pumps, which is a promising method to achieve the miniaturization and integration of the EOF pump in microfluidic systems. The non-contact liquid electrodes have no influence on the fluid in the Pumping channel when Pumping, reducing Joule heat generation and preventing gas bubble formation at the surface of electrodes. The pump has great potential to drive a wide range of fluids, such as drug reagents, cell suspensions and biological macromolecule solutions.
Guofu Zhou - One of the best experts on this subject based on the ideXlab platform.
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effect of fabrication parameters on capillary Pumping Performance of multi scale composite porous wicks for loop heat pipe
Applied Thermal Engineering, 2018Co-Authors: Rui Zhou, Yong Tang, Biao Tang, Yong Deng, Guofu ZhouAbstract:Abstract In this study, a new multi-scale composite porous wick (MCPW) is proposed for the loop heat pipe to guarantee the thermal reliability of the microelectronics packages. The MCPW, which is featured with the nanostructures distributed on the sintered copper powders, can effectively enhance the capillary Performance through modifying the properties of the copper powders. In this study, a number of MCPWs were developed by the sintering and alloying-dealloying treatment. Based on the infrared radiation (IR) thermal imaging method, the capillary rate-of-rise tests were used to the evaluate the capillary Pumping Performance, and the effects of the porous substrate and nanostructures were investigated in detail. The results indicated that morphologies of the copper powders, including powder size and powder type, would influence the capillary Performance. The larger powder size and irregular type were better for liquid rise. Meanwhile, nanostructures on the powder surface played a dominant role in forming the hydrophilic surface on the copper powders, which could achieve the higher capillary height and rising velocity of working fluid for the wick. The optimum choice for the nanostructures formation was NaOH solution under the corrosive time 24 h.
