Heat transfer model for evaporation in microchannels. Part I: presentation of the model
01 Jul 2004-International Journal of Heat and Mass Transfer (Pergamon)-Vol. 47, Iss: 14, pp 3375-3385
TL;DR: In this article, a three-zone flow boiling model was proposed to describe evaporation of elongated bubbles in microchannels, and a time-averaged local heat transfer coefficient was obtained.
About: This article is published in International Journal of Heat and Mass Transfer.The article was published on 2004-07-01. It has received 560 citations till now. The article focuses on the topics: Convective heat transfer & Heat transfer coefficient.
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TL;DR: In this paper, the authors present an exhaustive review of the literature in this area and suggest a direction for future developments, including heat transfer, material science, physics, chemical engineering and synthetic chemistry.
Abstract: Suspended nanoparticles in conventional fluids, called nanofluids, have been the subject of intensive study worldwide since pioneering researchers recently discovered the anomalous thermal behavior of these fluids. The enhanced thermal conductivity of these fluids with small-particle concentration was surprising and could not be explained by existing theories. Micrometer-sized particle-fluid suspensions exhibit no such dramatic enhancement. This difference has led to studies of other modes of heat transfer and efforts to develop a comprehensive theory. This article presents an exhaustive review of these studies and suggests a direction for future developments. The review and suggestions could be useful because the literature in this area is spread over a wide range of disciplines, including heat transfer, material science, physics, chemical engineering and synthetic chemistry.
1,069 citations
01 Aug 1953
TL;DR: In this paper, a solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius, since the radius at which it becomes valid is near the lower limit of experimental observation.
Abstract: The growth of a vapor bubble in a superheated liquid is controlled by three factors: the inertia of the liquid, the surface tension, and the vapor pressure. As the bubble grows, evaporation takes place at the bubble boundary, and the temperature and vapor pressure in the bubble are thereby decreased. The heat inflow requirement of evaporation, however, depends on the rate of bubble growth, so that the dynamic problem is linked with a heat diffusion problem. Since the heat diffusion problem has been solved, a quantitative formulation of the dynamic problem can be given. A solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius. This asymptotic solution covers the range of physical interest since the radius at which it becomes valid is near the lower limit of experimental observation. It shows the strong effect of heat diffusion on the rate of bubble growth. Comparison of the predicted radius‐time behavior is made with experimental observations in superheated water, and very good agreement is found.
729 citations
TL;DR: In this paper, a review of recent research on boiling in micro-channels is presented, which addresses the topics of macroscale versus micro-scale heat transfer, two-phase flow regimes, flow boiling heat transfer results for micro-channel, heat transfer mechanisms in microchannels and flow boiling models for micro channels.
553 citations
TL;DR: In this paper, a literature review is presented to compare different cooling technologies currently in development in research laboratories that are competing to solve the challenge of cooling the next generation of high heat flux computer chips.
Abstract: The purpose of this literature review is to compare different cooling technologies currently in development in research laboratories that are competing to solve the challenge of cooling the next generation of high heat flux computer chips. Today, most development efforts are focused on three technologies: liquid cooling in copper or silicon micro-geometry heat dissipation elements, impingement of liquid jets directly on the silicon surface of the chip, and two-phase flow boiling in copper heat dissipation elements or plates with numerous microchannels. The principal challenge is to dissipate the high heat fluxes (current objective is 300 W/cm2) while maintaining the chip temperature below the targeted temperature of 85°C, while of second importance is how to predict the heat transfer coefficients and pressure drops of the cooling process. In this study, the state of the art of these three technologies from recent experimental articles (since 2003) is analyzed and a comparison of the respective merits and ...
511 citations
TL;DR: In this article, a composite correlation is developed from a database of 3899 data points from 14 studies in the literature covering 12 different wetting and non-wetting fluids, hydraulic diameters ranging from 016 to 292mm, and confinement numbers from 03 to 40.
333 citations
References
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TL;DR: In this paper, a systematic experimental investigation of two-phase flow patterns in microchannels was the objective of this study, using air and water, experiments were conducted in circular micro channels with 1.1 and 1.45mm inner diameters, and in semi-triangular (triangular with one corner smoothed) cross-sections with hydraulic diameters 1.09 and 149mm.
822 citations
TL;DR: The expression Y = (1 + Zn)1/n where Y and Z are expressed in terms of the solutions for asymptotically large and small values of the independent variable is shown to be remarkably successful in correlating rates of transfer for processes which vary uniformly between these limiting cases as discussed by the authors.
Abstract: The expression Y = (1 + Zn)1/n where Y and Z are expressed in terms of the solutions for asymptotically large and small values of the independent variable is shown to be remarkably successful in correlating rates of transfer for processes which vary uniformly between these limiting cases. The arbitrary exponent n can be evaluated simply from plots of Y versus Z and Y/Z versus 1/Z. The expression is quite insensitive to the choice of n and the closest integral value can be chosen for simplicity. The process of correlation can be repeated for additional variables in series. Illustrative applications are presented only for flow, conduction, forced convection, and free convection, but the expression and procedure are applicable to any phenomenon which varies uniformly between known, limiting solutions.
784 citations
TL;DR: In this article, a solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius, since the radius at which it becomes valid is near the lower limit of experimental observation.
Abstract: The growth of a vapor bubble in a superheated liquid is controlled by three factors: the inertia of the liquid, the surface tension, and the vapor pressure. As the bubble grows, evaporation takes place at the bubble boundary, and the temperature and vapor pressure in the bubble are thereby decreased. The heat inflow requirement of evaporation, however, depends on the rate of bubble growth, so that the dynamic problem is linked with a heat diffusion problem. Since the heat diffusion problem has been solved, a quantitative formulation of the dynamic problem can be given. A solution for the radius of the vapor bubble as a function of time is obtained which is valid for sufficiently large radius. This asymptotic solution covers the range of physical interest since the radius at which it becomes valid is near the lower limit of experimental observation. It shows the strong effect of heat diffusion on the rate of bubble growth. Comparison of the predicted radius‐time behavior is made with experimental observations in superheated water, and very good agreement is found.
771 citations
TL;DR: In this paper, an experiment was carried out to investigate the characteristics of the evaporation heat transfer and pressure drop for refrigerant R-134a flowing in a horizontal small circular pipe having an inside diameter of 2.0 mm.
367 citations
TL;DR: In this paper, the authors present a Web of Science Record created on 2005-07-06, modified on 2017-05-10 for a paper entitled "Reference LTCM-ARTICLE-2005-032:
Abstract: Reference LTCM-ARTICLE-2005-032View record in Web of Science Record created on 2005-07-06, modified on 2017-05-10
189 citations