wall Superheat Excursions in the Boiling incipience of Dielectric Fluids
TL;DR: In this paper, a brief review of the mechanisms that may be responsible for delayed nucleation and examines the limited literature on incipience superheat excursions is presented. But the authors do not consider the effect of temperature variations on the nucleation of microelectronic components.
Abstract: Many of the candidate fluids for immersion cooling of microelectronic components possess both low surface tension and high gas solubility. As a consequence, ebullient heat transfer with such fluids is accompanied by nucleation anomalies and a frequently observed wall temperature overshoot. The difficulty in preventing this thermal excursion and in predicting its magnitude constrains the development of immersion cooling systems. This paper begins with a brief review of the mechanisms that may be responsible for delayed nucleation and examines the limited literature on incipience superheat excursions.
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TL;DR: In this paper, two benign methods of generating surface microstructures, spraying and painting, were applied to a rectangular, horizontally oriented surface, and provided up to a 85% reduction in incipient superheat.
Abstract: Two benign methods of generating surface microstructures, "spraying" and "painting", provide pool boiling heat transfer enhancement. The methods do not require the target surface to be exposed to high stress environments, making them applicable to electronic component surfaces. The painted surface microstructures are applied to a rectangular, horizontally oriented surface, and provide up to a 85% reduction in incipient superheat. Between a 70 and 80% reduction in nucleate boiling superheats, and as much as a 100% increase in the maximum heat flux (critical heat flux-CHF), beyond that of the nontreated reference surface. The surface microstructures are also applied to a silicon test chip and tested at saturated and sub-cooled (45/spl deg/C) conditions using FC-72. At sub-cooled conditions, heat dissipation rates of 100 W/cm/sup 2/ were provided at junction temperatures of 85/spl deg/C, and the highest CHF observed was 159 W/cm/sup 2/, 224% higher than that from the untreated chip surface at saturated conditions. >
60 citations
TL;DR: In this article, the authors investigated the relationship between the liquid cavitation, the boiling and the micro bubble radii and showed that cavitation bubbles have an important influence on the nucleation, growth and collapse of vapor embryo within cavities on the heat transfer surface.
55 citations
TL;DR: In this article, a review consolidates a large number of pool boiling experimental data for dielectric and other highly wetting liquids subject to engineered surfaces with elaborating the related augmentation mechanisms.
43 citations
TL;DR: In this paper, a new type of hysteresis, termed temperature deviation (TD), is described and the physical mechanisms for both TOS and TD are analyzed in detail using thermodynamic nucleation.
41 citations
01 Jan 1997
TL;DR: In this paper, it was shown that the transistor, with its relatively low power requirements, would greatly minimize, if not totally eliminate, all cooling concerns, and such thoughts, however, were short lived, as engineers sought to improve performance, cost, and reliability by packaging greater numbers of circuits in an ever smaller space.
Abstract: It was thought that the invention of the transistor, with its relatively low power requirements, would greatly minimize, if not totally eliminate, all cooling concerns. Such thoughts, however, were short lived, as engineers sought to improve performance, cost, and reliability by packaging greater numbers of circuits in an ever-smaller space. In fact, power densities at the component level have increased dramatically over the years. In mainframe computers, chips may be found with power dissipations ranging between 20 and 40 W, and chips with power dissipation in excess of 10 W may be found in many PC and workstation applications. Considering one example from a mainframe computer, a 7 × 7-mm chip dissipating 30 W, results in a heat flux of more than 6 × 105 W/m2. As shown in Figure 4-1, this is only about two orders of magnitude less than that on the surface of the sun [1]. But the sun’s surface temperature is 6000°C, compared to a maximum operating temperature in the range of 100°C for a typical semiconductor chip.
39 citations
References
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Book•
01 Jan 1994
TL;DR: In this paper, the basic models of two-phase flow are discussed and empirical treatments of two phase flow are provided. But the authors focus on convective boiling and condensing.
Abstract: Introduction 1. The basic models 2. Empirical treatments of two-phase flow 3. Introduction to convective boiling 4. Subcooled boiling heat transfer 5. Void fraction and pressure drop in subcooled boiling 6. Saturated boiling heat transfer 7. Critical heat flux in forced convective flow - 1. Vertical uniformly heated tubes 8. Critical heat flux in forced convective flow - 2. More complex situations 9. Condensation 10. Conditions influencing the performance of boiling and condensing systems 11. Multi-component boiling and condensation Appendix Index
2,426 citations
TL;DR: In this article, a regression analysis was applied to the nearly 5000 existing experimental data points for natural convection boiling heat transfer, which can best be represented by subdividing the substances into four groups (water, hydrocarbons, cryogenic fluids and refrigerants) and employing a different set of dimensionless numbers for each group of substances.
710 citations
Book•
01 Jan 1983
TL;DR: In this article, thermal analysis and control of electronic equipment, thermal analysis of electronic devices and their control, thermal control and control in the field of software engineering, is discussed. ǫ
Abstract: Thermal analysis and control of electronic equipment , Thermal analysis and control of electronic equipment , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
339 citations
TL;DR: A survey of the evolution of surface geometries that promote high-performance nucleate boiling can be found in this paper, where the authors survey the development of a high area density of stable nucleation sites whose performance does not deteriorate with time.
Abstract: This paper surveys the evolution of special surface geometries that promote high-performance nucleate boiling. Early work by Jakob and Fritz in 1931 showed that emery paper roughening or machined grooves provided only temporary performance increase. However, this improvement dissipated after a few days to the flat surface value. There was little sustained interest in this unique, but apparently unuseful, phenomenon until the mid-1950s. During the period 1955-1965, supporting fundamental studies of the character and stability of nucleation sites provided a basis for renewed efforts to develop a high area density of stable, artificially formed nucleation sites whose performance does not deteriorate with time. Beginning in 1968 industrial research produced patented technology that achieved the long-sought goal. In 1980 at least six high-performance nucleate boiling surfaces were commercially available. The technology reported in this paper represents a dramatic advance in the field of heat transfer.
192 citations