[...]... state of the art in highheat flux management schemes, pressure and temperature measurement, pressure drop and heat transfer in single-phase and two-phase micro-channels, design and fabrication of micro-channel heat sinks are discussed 2.1 High -Heat Flux Management Schemes With the trend towards increasing levels of integration in high-density, very largescale integral circuits and heat sink technologies,... Heat Transfer and Boiling in Micro-Channels © Springer 2009 1 2 1 Introduction 1.2 Scope and Contents of Part I The first part of this book deals with the characteristics of flow and heat transfer in the channels and comparison between conventional size and micro-channels, which are important to understanding micro-processes in cooling systems of electronic devices with high power density and many other... transient and turbulent single-phase flows; (2) heat transfer of liquids and gas flows; and (3) two-phase flows in adiabatic and heated micro-channels As indicated by Kandlikar and Grande (2002), and by Hetsroni et al (2005a, c), no fundamental change occurs in single-phase flow in the absence of rarefaction effects, which for gases are described by the Knudsen number, Kn, and are significant in the range... over the heated surface is increased with the aid of a pump Boiling is a convective heat transfer process based on the phase change of the working fluid with vapor bubbles forming at the heated surface, and commonly has the form of pool boiling or flow boiling The boiling curve (Fig 2.6, Simons 1996) for a typical fluorocarbon coolant shows the Fig 2.6 Typical heat transfer regimes for immersion cooling with... developments in micro-scale heat transfer and fluid flow have been discussed by e.g Zhang et al (2004), Celata (2004), Kakac et al.(2005), Kandlikar et al (2005), Zhang (2007) In spite of the progress described above, certain fundamental problems in flow and heat transfer are still unclear This leads to difficulties in understanding the essence of micro-thermohydrodynamic phenomena L.P Yarin, Fluid Flow, Heat Transfer. .. pushed even further by recourse to boiling In addition to offering higher heat transfer coefficients, boiling convection in microchannels is promising because it requires less pumping power than its single-phase liquid counterpart to achieve a given heat sink thermal resistance For the same heat flux the pressure drops by a factor of 20 A review on boiling and evaporation in small-diameter channels was published... dissipation, axial conduction and wall roughness on the thermal characteristics of flow Specific problems connected with electro-osmotic heat transfer in micro-channels, three-dimensional heat transfer in micro-channel heat sinks and optimization of micro -heat exchangers are also discussed The results of experimental and theoretical investigations related to study of drag and heat transfer in two-phase gas–liquid... at a heat flux level of q = 40 W/cm2 has been reported Liquid cooling Liquid cooling in electronics is generally divided into two main categories, indirect and direct, according to the type of contact between the coolant and the cooled components The following sections discuss the two categories, represented by heat pipes and cold plates, and immersion cooling and jet impingement, respectively Heat. .. presented in Chap 5 The concepts of boiling in micro-channels and comparison to conventional size channels are considered in Chap 6 The mechanism of the onset of nucleate boiling is treated Specific problems such as explosive boiling in parallel micro-channels, drag reduction and heat transfer in surfactant solutions are also considered Chapter 7 deals with the practical problems It contains the results... impingement (as shown in Fig 2.7) are often considered as competing options for electronics cooling In general, spraying requires lower flow rates but a higher nozzle pressure drop In recent years spray cooling has received increasing attention as a means of supporting higher heat fluxes In it the liquid is disintegrated into fine droplets that impinge individually on the heated wall The cooling effect is achieved . alt="" Heat and Mass Transfer Editorial Board D. Mewes F. Mayinger L.P. Yarin · A. Mosyak · G. Hetsroni Fluid Flow, Heat Transfer and Boiling in Micro-Channels 123 L.P. Yarin Technion-Israel Institute. example, contain components that require continuous L.P. Yarin, Fluid Flow, Heat Transfer and Boiling in Micro-Channels 7 © Springer 2009 8 2 Cooling Systems of El ectronic Devices Fig. 2.1 International. 332 7.3 Boilin g in Micro-Channels . . 333 7.3.1 Boiling Incipience . . . 333 7.3.2 FlowBoiling:PressureDropCharacteristics 335 7.3.3 FlowBoiling:HeatTransfer 336 7.3.4 Natural Convection Boiling 339 7.3.5