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 article, the critical heat flux (CHF) was accompanied by dryout of the subfilm after total separation of the liquid near the upstream edge of the heater, which correlated favorably with predictions of a CHF model based on the Helmholtz instability and subfilm dryout.
83 citations
05 Feb 1992
TL;DR: Particle layering is introduced as an effective and convenient technique for enhancing boiling nucleation on a surface as discussed by the authors, which can be applied without stress or damage to a surface, it can be implemented in immersion cooling, with boiling, of electronic equipment components.
Abstract: Particle layering is introduced as an effective and convenient technique for enhancing boiling nucleation on a surface. Because it can be applied without stress or damage to a surface, it can be implemented in immersion cooling, with boiling, of electronic equipment components. Such an enhanced surface, which has an increased number of nucleation sites, shows a decreased level of wall superheat under boiling and an increased critical heat flux relative to superheat and critical heat flux values for an untreated surface. Application of this technique results in a decrease of heated surface temperature and a more uniform temperature of the heated surface; both effects are important in immersion cooling of electronic equipment. >
83 citations
TL;DR: In this paper, the effect of fin dimensions, spacing and pressure on heat transfer in saturated pool boiling was examined, in particular the effect which the non-uniform distribution of fin produces on boiling behaviour was analyzed.
70 citations
TL;DR: In this article, the effects on the boiling curve of having air dissolved in the fluid are documented, showing that fluid in the vicinity of the heating element is apparently liberated of dissolved gas during boiling.
Abstract: Experimental results on pool boiling heat transfer from a horizontal cylinder in an electronic cooling fluid (FC-72) are presented. The effects on the boiling curve of having air dissolved in the fluid are documented, showing that fluid in the vicinity of the heating element is apparently liberated of dissolved gas during boiling. Dissolved gas was found to influence boiling incipience only with high gas concentrations (>0.005 moles/mole). For low-to-moderate concentrations, a larger superheat is required to initiate boiling and a hysteresis is observed between boiling curves taken with increasing and decreasing heat flux steps. Boiling, a very effective mode of heat transfer, is attractive for electronics cooling. The present experiment provides further documentation of the role of dissolved gas on the incipience process and shows similarities with subcooled boiling of a gas-free fluid. 20 refs., 8 figs., 1 tab.
60 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