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Tsinghua Science and Technology

Issue 2 • Date April 2002

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Displaying Results 1 - 22 of 22
  • [Front cover]

    Publication Year: 2002, Page(s): c1
    IEEE is not the copyright holder of this material | PDF file iconPDF (275 KB)
    Freely Available from IEEE
  • Contents

    Publication Year: 2002, Page(s): 1
    IEEE is not the copyright holder of this material | PDF file iconPDF (101 KB)
    Freely Available from IEEE
  • Nonlinear bubbling and micro-convection at a submerged orifice

    Publication Year: 2002, Page(s):97 - 108
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (4349 KB)

    The present paper describes the nonlinear behavior of bubble formation from a single submerged orifice and induced liquid motion (micro-convection) surrounding the bubble. The experimental data reveals that departing periods of successive bubbles evolve multiple periods from single to triple periods when the gas flow rate is increased and that the micro-convection evolves bifurcation phenomena sim... View full abstract»

    Open Access
  • What is going on in a critical thermosyphon?

    Publication Year: 2002, Page(s):109 - 115
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1898 KB)

    Critically filled thermosyphons for heat transport differ in size and temperature distribution from critically filled testcells for property research. Consequently, the thermodynamic states within a thermosyphon are distributed more heterogeneously. In a glass thermosyphon, flows and phase distributions were observed. A break-down of the heat transport mechanism was found as a consequence of flood... View full abstract»

    Open Access
  • Recent developments in cooling using blowing

    Publication Year: 2002, Page(s):116 - 134
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1760 KB)

    Influence of the blowing through a porous flat plate and a circular cylinder has been studied. Experimental and numerical results agree and show a thickening of the boundary layers, both dynamic and thermal. The thermal protection effectiveness has been quantified for the two geometries, and comparisons between discrete injection and blowing, in the case of the flat plate, were carried out, showin... View full abstract»

    Open Access
  • Transient behaviour of a heat pipe with extracapillary circulation

    Publication Year: 2002, Page(s):135 - 145
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (1409 KB)

    Heat pipe devices, for their typical working mode, are particularly suitable for zero gravity applications, and have also been considered for applications in space satellites with nuclear generators because of the absence of active systems for the coolant circulation. The present work reports the results of experimental tests carried out on a heat pipe facility designed to investigate the thermal-... View full abstract»

    Open Access
  • Heat transfer characteristics of wavy-wall channels in micropolar fluids

    Publication Year: 2002, Page(s):146 - 154
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (604 KB)

    Forced convection flow through a sinusoidally curved converging-diverging channel in micropolar fluids has been investigated numerically. A simple coordinate transformation is employed to transform the complex wavy-wall channel to a parallel-plate channel, and the cubic spline alternating-direction implicit method is then used to solve the flow patterns and heat transfer characteristics. The effec... View full abstract»

    Open Access
  • Using boiling for treating waste activated sludge

    Publication Year: 2002, Page(s):155 - 159
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (659 KB)

    In this work we investigated the feasibility of using short time, low superheat boiling to treat biological sludge. The treated sludge exhibited reduced filterability and enhanced settleability. The boiling treatment released a large amount of extra-cellular polymers (ECPs) from the solid phase and reduced the microbial density levels of the total coliform bacteria and the heterotrophic bacteria. ... View full abstract»

    Open Access
  • Bubble interaction in thermal boundary layers

    Publication Year: 2002, Page(s):160 - 164
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (332 KB)

    The boiling process is characterized by strong nonlinear interactions between bubbles in the thermal boundary layer. The present paper uses a heat balance approach to derive the interaction length between bubbles based on boiling heat transfer mechanisms and bubble dynamics. The effects of some important parameters on the interaction length are then analyzed. Interestingly, the whole range of flux... View full abstract»

    Open Access
  • Cryogenic thermophysical studies for clinical medicine

    Publication Year: 2002, Page(s):165 - 170
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (407 KB)

    Cryogenic technology has been widely used in clinical medicine and in pharmaceutics, so thermophysical studies are extremely important to solve problems during freezing and thawing. This paper reports some recent research in clinical medicine, including cryo-injury, cryosurgery, and cryopreservation of some important cells and tissues. Microscopic images of the freezing process with a cryomicrosco... View full abstract»

    Open Access
  • Similarity solution for convection heat transfer due to Marangoni flow over a flat surface

    Publication Year: 2002, Page(s):171 - 176
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (407 KB)

    Marangoni convection occurs along any liquid-vapor interface that has a surface tension gradient. The surface tension gradient can result from either temperature or concentration gradients along the surface. Marangoni convection is of importance in crystal growth melts and during boiling as it influences the flow around the vapor bubbles. The influence of Marangoni induced convection is more obvio... View full abstract»

    Open Access
  • Heat transfer in flue gas with vapor condensation

    Publication Year: 2002, Page(s):177 - 181
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (322 KB)

    This paper combines the film model with Nusselt's condensation theory to analyze the effects of water vapor condensation on the heat transfer performance of flue gas flowing through a vertical tube. The analysis compares the condensation and convective heat transfer rates. For the concentration range investigated, the water vapor condensation transfers more energy than the flue gas convection, but... View full abstract»

    Open Access
  • Shear force distribution and heat transfer in laminar boundary layer flows for power law fluid

    Publication Year: 2002, Page(s):182 - 186
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (349 KB)

    Analytical and numerical solutions are presented for the momentum and energy laminar boundary layer equations in power law fluids utilizing a similarity transformation and the shooting technique. The results indicated that for power law exponents 0 < n ≤ 1, the skin friction σ decreases with increasing n, and the dimensionless shear force decreases with increasing dimensionles... View full abstract»

    Open Access
  • Explicit analytical solutions of coupled fluid flow transfer equation in heterogeneous porous media

    Publication Year: 2002, Page(s):187 - 189
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (218 KB)

    Explicit analytical solutions are presented for the coupled fluid flow transfer equation in heterogeneous porous media. These analytical solutions are useful for their description of actual flow fields and as benchmark solutions to check the rapidly developing numerical calculations and to study various computational methods such as the discrete approximations of the governing equations and grid g... View full abstract»

    Open Access
  • Exergy analysis of methanol-IGCC Polygeneration technology based on coal gasification

    Publication Year: 2002, Page(s):190 - 193
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (319 KB)

    Polygeneration is a key strategy for making ultra-clean energy products highly competitive with conventional energy systems. A polygeneration system based on coal gasification was analyzed using the exergy method to calculate the system thermal efficiency. The results show that the polygeneration system has less pollutants and higher efficiency than the separate systems. View full abstract»

    Open Access
  • Discontinuous operation of geothermal heat exchangers

    Publication Year: 2002, Page(s):194 - 197
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (282 KB)

    Ground-source heat pump (GSHP) systems for HV AC have aroused more and more interest in China in recent years because of their higher energy efficiency compared with conventional systems. The design and performance simulation of the geothermal heat exchangers is vital to the success of this technology. In GSHP systems, the load of the geothermal heat exchanger varies greatly and is usually discont... View full abstract»

    Open Access
  • Experimental viscosity measurements for copper oxide nanoparticle suspensions

    Publication Year: 2002, Page(s):198 - 201
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (258 KB)

    The viscosity of water with copper oxide nanoparticle suspensions was measured using capillary viscometers. The mass fractions of copper oxide nanoparticles in the experiment, w, varied between 0.02 and 0. 10, and the temperature range was 30°C to 80°C. The experimental results show that the temperature was the major factor affecting the viscosity of the nanoparticle suspensions, whi... View full abstract»

    Open Access
  • Forced convection heat transfer in plate channels filled with packed beds or sintered porous media

    Publication Year: 2002, Page(s):202 - 208
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (492 KB)

    In the present work, forced convection heat transfer in plate channels filled with metallic or non-metallic particles (packed beds) or sintered porous media is simulated numerically using a thermal non-equilibrium model. The numerical simulation results are compared with experimental data. The difference between convection heat transfer in packed beds and in sintered porous media and the effects o... View full abstract»

    Open Access
  • Boiling heat transfer on porous surfaces with vapor channels

    Publication Year: 2002, Page(s):209 - 212
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (299 KB)

    Boiling heat transfer on porous coated surfaces with vapor channels was investigated experimentally to determine the effects of the size and density of the vapor channels on the boiling heat transfer. Observations showed that bubbles escaping from the channels enhanced the heat transfer. Three regimes were identified: liquid flooding, bubbles in the channel and the bottom drying out region. The ma... View full abstract»

    Open Access
  • Introdution to institute of engineering thermophysics, department of thermal engineering, Tsinghua University

    Publication Year: 2002, Page(s): 213
    IEEE is not the copyright holder of this material | PDF file iconPDF (69 KB)
    Open Access
  • Tsinghua Develops World's Thinnest Ultrasonic Motor

    Publication Year: 2002, Page(s): 201
    IEEE is not the copyright holder of this material | PDF file iconPDF (81 KB)
    Open Access
  • THSCAN large container stationary inspection system in service

    Publication Year: 2002, Page(s): 208
    IEEE is not the copyright holder of this material | PDF file iconPDF (76 KB)
    Open Access

Aims & Scope

Tsinghua Science and Technology (Tsinghua Sci Technol) aims to highlight scientific achievements in computer science, electronic engineering, and other IT fields. Contributions all over the world are welcome.

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Meet Our Editors

Editor-in-Chief
Professor Jiaguang Sun
School of Software
Tsinghua University
Beijing  100084 China
journal@tsinghua.edu.cn
Phone:86-10-62771385