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Yutaka Asako

Bio: Yutaka Asako is an academic researcher from Universiti Teknologi Malaysia. The author has contributed to research in topics: Heat transfer & Turbulence. The author has an hindex of 25, co-authored 227 publications receiving 2351 citations. Previous affiliations of Yutaka Asako include Tokyo Metropolitan University & Nagaoka University of Technology.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a two-dimensional flow and heat transfer model is used to study gas compressibility and rarefaction in microchannels assuming a slip flow regime, where the compressible forms of momentum and energy equations are solved with slip velocity and temperature jump boundary conditions in a parallel plate channel for both uniform wall temperature and uniform wall heat flux boundary conditions.
Abstract: A two-dimensional flow and heat transfer model is used to study gas compressibility and rarefaction in microchannels assuming a slip flow regime. The compressible forms of momentum and energy equations are solved with slip velocity and temperature jump boundary conditions in a parallel plate channel for both uniform wall temperature and uniform wall heat flux boundary conditions. The numerical methodology is based on the control volume finite difference scheme. To verify the model, the mass flow rate was compared with the experimental results of helium through a microchannel. Also, the normalized friction coefficient was compared with the experiments for nitrogen and helium flow in a microchannel. Finally, the axial pressure distribution was compared with the experimental results for nitrogen flow in a microchannel. The computations were performed for a wide range of knin, Re, dimensionless distance from the entrance, and for the wall parameters q∗ and T∗, to study the effects of rarefaction and compressi...

135 citations

Journal ArticleDOI
TL;DR: In this article, a finite volume methodology was developed to predict fully developed heat transfer coefficients, friction factors, and streamlines for flow in a corrugated duct, which can be adopted for other convection-diffusion problems in which two boundaries of the flow domain do not lie along the coordinate lines.
Abstract: A finite volume methodology was developed to predict fully developed heat transfer coefficients, friction factors, and streamlines for flow in a corrugated duct. The basis of the method is an algebraic coordinate transformation which maps the complex fluid domain onto a rectangle. The method can be adopted for other convection-diffusion problems in which two boundaries of the flow domain do not lie along the coordinate lines. Representative results were found for laminar flow uniform wall temperature, and for a range of Reynolds number, Prandtl number, corrugation angle, and dimensionless interwall spacing. As seen from the streamlines, the flow patterns are highly complex including large recirculation zones. The pressure drops and friction factor results are higher than the corresponding values for a straight duct. Finally, the performance of the corrugated duct was compared with the straight duct under three different constraints - fixed pumping power, fixed pressure drop, and fixed mass flow rate. There are small differences in the heat transfer rate ratios under these constraints.

116 citations

Journal ArticleDOI
TL;DR: In this article, the effect of three geometrical parameters; relative width of secondary channel (λ), relative rib width (β), and angle of secondary channels (θ) on the convective heat transfer and pressure drop have been investigated.

91 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of compressibility on gaseous flow characteristics in micro-channels was investigated using the Lagrangian-Eulerian method based on the product of friction factor and Reynolds number expressed as a function of both Reynolds number and Mach number.

82 citations

Journal ArticleDOI
TL;DR: In this paper, an approach that can determine the flow rate with consideration of the pressure drop is proposed, and a comparison is made with Kettleborough's and Aihara's results.
Abstract: A few numerical analyses of the free convection between two heated parallel plates have been carried out without using the boundary-layer approximation. In this paper, an approach that can determine the flow rate with consideration of the pressure drop is proposed. As an example of the calculation, the method is applied to Kettleborough's model. In addition, a comparison is made with Kettleborough's and Aihara's results.

71 citations


Cited by
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01 Jan 2007

1,932 citations

01 Jan 2016
TL;DR: The numerical heat transfer and fluid flow is universally compatible with any devices to read and is available in the authors' digital library an online access to it is set as public so you can get it instantly.
Abstract: Thank you for reading numerical heat transfer and fluid flow. Maybe you have knowledge that, people have search numerous times for their favorite books like this numerical heat transfer and fluid flow, but end up in infectious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some malicious virus inside their computer. numerical heat transfer and fluid flow is available in our digital library an online access to it is set as public so you can get it instantly. Our books collection spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the numerical heat transfer and fluid flow is universally compatible with any devices to read.

1,531 citations

BookDOI
27 Sep 2001
TL;DR: In this paper, the authors present a detailed overview of the history of the field of flow simulation for MEMS and discuss the current state-of-the-art in this field.
Abstract: Part I: Background and Fundamentals Introduction, Mohamed Gad-el-Hak, University of Notre Dame Scaling of Micromechanical Devices, William Trimmer, Standard MEMS, Inc., and Robert H. Stroud, Aerospace Corporation Mechanical Properties of MEMS Materials, William N. Sharpe, Jr., Johns Hopkins University Flow Physics, Mohamed Gad-el-Hak, University of Notre Dame Integrated Simulation for MEMS: Coupling Flow-Structure-Thermal-Electrical Domains, Robert M. Kirby and George Em Karniadakis, Brown University, and Oleg Mikulchenko and Kartikeya Mayaram, Oregon State University Liquid Flows in Microchannels, Kendra V. Sharp and Ronald J. Adrian, University of Illinois at Urbana-Champaign, Juan G. Santiago and Joshua I. Molho, Stanford University Burnett Simulations of Flows in Microdevices, Ramesh K. Agarwal and Keon-Young Yun, Wichita State University Molecular-Based Microfluidic Simulation Models, Ali Beskok, Texas A&M University Lubrication in MEMS, Kenneth S. Breuer, Brown University Physics of Thin Liquid Films, Alexander Oron, Technion, Israel Bubble/Drop Transport in Microchannels, Hsueh-Chia Chang, University of Notre Dame Fundamentals of Control Theory, Bill Goodwine, University of Notre Dame Model-Based Flow Control for Distributed Architectures, Thomas R. Bewley, University of California, San Diego Soft Computing in Control, Mihir Sen and Bill Goodwine, University of Notre Dame Part II: Design and Fabrication Materials for Microelectromechanical Systems Christian A. Zorman and Mehran Mehregany, Case Western Reserve University MEMS Fabrication, Marc J. Madou, Nanogen, Inc. LIGA and Other Replication Techniques, Marc J. Madou, Nanogen, Inc. X-Ray-Based Fabrication, Todd Christenson, Sandia National Laboratories Electrochemical Fabrication (EFAB), Adam L. Cohen, MEMGen Corporation Fabrication and Characterization of Single-Crystal Silicon Carbide MEMS, Robert S. Okojie, NASA Glenn Research Center Deep Reactive Ion Etching for Bulk Micromachining of Silicon Carbide, Glenn M. Beheim, NASA Glenn Research Center Microfabricated Chemical Sensors for Aerospace Applications, Gary W. Hunter, NASA Glenn Research Center, Chung-Chiun Liu, Case Western Reserve University, and Darby B. Makel, Makel Engineering, Inc. Packaging of Harsh-Environment MEMS Devices, Liang-Yu Chen and Jih-Fen Lei, NASA Glenn Research Center Part III: Applications of MEMS Inertial Sensors, Paul L. Bergstrom, Michigan Technological University, and Gary G. Li, OMM, Inc. Micromachined Pressure Sensors, Jae-Sung Park, Chester Wilson, and Yogesh B. Gianchandani, University of Wisconsin-Madison Sensors and Actuators for Turbulent Flows. Lennart Loefdahl, Chalmers University of Technology, and Mohamed Gad-el-Hak, University of Notre Dame Surface-Micromachined Mechanisms, Andrew D. Oliver and David W. Plummer, Sandia National Laboratories Microrobotics Thorbjoern Ebefors and Goeran Stemme, Royal Institute of Technology, Sweden Microscale Vacuum Pumps, E. Phillip Muntz, University of Southern California, and Stephen E. Vargo, SiWave, Inc. Microdroplet Generators. Fan-Gang Tseng, National Tsing Hua University, Taiwan Micro Heat Pipes and Micro Heat Spreaders, G. P. "Bud" Peterson, Rensselaer Polytechnic Institute Microchannel Heat Sinks, Yitshak Zohar, Hong Kong University of Science and Technology Flow Control, Mohamed Gad-el-Hak, University of Notre Dame) Part IV: The Future Reactive Control for Skin-Friction Reduction, Haecheon Choi, Seoul National University Towards MEMS Autonomous Control of Free-Shear Flows, Ahmed Naguib, Michigan State University Fabrication Technologies for Nanoelectromechanical Systems, Gary H. Bernstein, Holly V. Goodson, and Gregory L. Snider, University of Notre Dame Index

951 citations

Book ChapterDOI
28 Jan 2005
TL;DR: The Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K), thermal diffusivity: α, ≡ k/(ρ · Cp) (m /s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K).
Abstract: Geometry: shape, size, aspect ratio and orientation Flow Type: forced, natural, laminar, turbulent, internal, external Boundary: isothermal (Tw = constant) or isoflux (q̇w = constant) Fluid Type: viscous oil, water, gases or liquid metals Properties: all properties determined at film temperature Tf = (Tw + T∞)/2 Note: ρ and ν ∝ 1/Patm ⇒ see Q12-40 density: ρ ((kg/m) specific heat: Cp (J/kg ·K) dynamic viscosity: μ, (N · s/m) kinematic viscosity: ν ≡ μ/ρ (m/s) thermal conductivity: k, (W/m ·K) thermal diffusivity: α, ≡ k/(ρ · Cp) (m/s) Prandtl number: Pr, ≡ ν/α (−−) volumetric compressibility: β, (1/K)

636 citations