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Journal ArticleDOI

Thermal Design of Immersion Cooling Modules for Electronic Components

01 Dec 1983-Heat Transfer Engineering (Taylor & Francis Group)-Vol. 4, Iss: 3, pp 35-50

TL;DR: In this paper, a review of possible immersion cooling configurations and the thermal mechanisms active in vapor-space and submerged condenser modules is presented, with a focus on the operational limits and relations for predicting the performance of submerged condensers.

AbstractDirect immersion of electronic components in low-boiling point, dielectric fluids can provide a benign local ambience and accommodate substantial spatial and temporal power variations while minimizing component temperature excursions and failure rates. Following a review of possible immersion cooling configurations and the thermal mechanisms active in vapor-space and submerged condenser modules, attention is focused on the operational limits and relations for predicting submerged condenser performance. Finally, descriptions of three likely applications of submerged condenser technology are presented.

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Citations
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Patent
08 Mar 1991
TL;DR: A cooling system employs a cooling liquid and a cooling gas in a combined thermodynamic cycle to overcome the flow resistance of dense assemblies of heat generating components and to improve heat transfer by inducing turbulence, thereby reducing the effects of thermal hysteresis and boundary layer formation as mentioned in this paper.
Abstract: A cooling system employs a cooling liquid and a cooling gas in a combined thermodynamic cycle to overcome the flow resistance of dense assemblies of heat generating components and to improve heat transfer by inducing turbulence, thereby reducing the effects of thermal hysteresis and boundary layer formation. Sensible heat gain to the cooling liquid and gas and latent heat of vaporization of the cooling liquid also occur in channels through and over the components. The flow of cooling gas propels the cooling liquid through the channels. The cooling system is advantageous for cooling electronic components such as integrated circuits which exhibit relatively high degree of energy and physical density, in supercomputers. The cooling system may also be advantageously combined with an immersion cooling system for the power supply components in the computer.

121 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the transient bubble formation on polysilicon micro-resisters having dimensions of 95 μm in length, 10 μm or 5 µm in width, and 0.5 μm thickness.
Abstract: Transient bubble formation experiments are investigated on polysilicon micro-resisters having dimensions of 95 μm in length, 10 μm or 5 μm in width, and 0.5 μm in thickness. Micro resisters act as both resistive heating sources and temperature transducers simultaneously to measure the transient temperature responses beneath the thermal bubbles. The micro bubble nucleation processes can be classified into three groups depending on the levels of the input current. When the input current level is low, no bubble is nucleated. In the middle range of the input current, a single spherical bubble is nucleated with a waiting period up to 2 sec while the wall temperature can drop up to 8°C depending on the magnitude of the input current. After the formation of a thermal bubble, the resister temperature rises and reaches a steady state eventually. The bubble growth rate is found proportional to the square root of time that is similar to the heat diffusion controlled model as proposed in the macro scale boiling experiments. In the group of high input current, a single bubble is nucleated immediately after the current is applied

53 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used forced convective boiling in a cold-plate containing multiple miniature heat exchangers to develop heat transfer and pressure drop correlations valid for the flow conditions expected in miniature coldplate technology, experiments were conducted with R-134a as a working fluid.
Abstract: The miniaturization of electronic circuits, high power levels per chip, and increased packaging densities have driven the trend in electronic packaging toward higher heat fluxes. High performance cooling techniques are, therefore, required to keep junction temperatures low for acceptable reliability. To meet these requirements a new technology using forced convective boiling in a cold-plate containing multiple miniature heat exchangers is being developed. In order to develop heat transfer and pressure drop correlations valid for the flow conditions expected in miniature cold-plate technology, experiments were conducted with R-134a as a working fluid. The experimentation covered a wide-range of flow conditions in both single and two-phase flow conditions in linear and miniature helical flow passages. Eight test sections of different curvatures and channel sizes were built and experimented. Using both the single- and two-phase flow in these test sections, single- and two-phase flow pressure drop and heat transfer characteristics were experimentally investigated. The effect of curvature on these parameters was analyzed in relation to miniature channels. The results were then correlated to appropriate parameters of helical channels of different curvatures. This paper presents the pressure drop results for single and two-phase flow in linear and curvilinear passages.

42 citations

Journal ArticleDOI
TL;DR: In this article, a flat, smooth surface immersed in saturated highly wetting liquids, FC-72 and FC-87, is used as a heat transfer surface, simulating a microelectronic chip surface.
Abstract: The present research is an experimental study of pool boiling nucleation behavior using flat, smooth surfaces immersed in saturated highly wetting liquids, FC-72 and FC-87. A flush-mounted, copper surface of 10 mm × 10 mm is used as a heat transfer surface, simulating a microelectronic chip surface. At the nucleation incipient points of higher wall superheats with steady increase of heat flux, vapor film blankets the smooth surface and remains on the surface. To predict this film boiling incipience phenomenon from the smooth surface, an incipience map is developed over the boiling curve. When the incipient heat flux is higher than the minimum heat flux (MHF) and the incipient wall superheat value is higher than the transition boiling curve value at the incipient heat flux, the transition from single-phase natural convection to film boiling is observed at the incipient point. To prevent film boiling incipience, a microporous coating is applied over the smooth surface, which decreases incipient wall superheat and increases minimum heat flux. The film boiling incipience should be avoided to take advantage of highly efficient nucleate boiling heat transfer for the cooling of high-heat-flux applications.

31 citations

Proceedings ArticleDOI
11 May 1988
TL;DR: The thermal aspects of an immersion-cooled computer designed to operate at cryogenic temperatures are discussed in detail in this paper, including the selection of a working fluid, the determination of the mode, or modes, of heat transfer to be used, and the selection, or development, of any required heat transfer correlations.
Abstract: The thermal aspects are discussed of an immersion-cooled computer designed to operate at cryogenic temperatures. Several of the major thermal design issues are discussed in detail. These include: (1) the selection of a working fluid; (2) the determination of the mode, or modes, of heat transfer to be used: (3) the selection, or development, of any required heat transfer correlations; and (4) the selection of a refrigeration system. The results of a preliminary analysis of a candidate thermal control system are also presented. >

20 citations


References
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Journal ArticleDOI
TL;DR: In this article, a wide-ranging analytical investigation of laminar film condensation is presented, which includes interfacial resistance, superheating, free convection due to both temperature and concentration gradients, mass diffusion and thermal diffusion, and variable properties in both the liquid and the gas-vapor regions.
Abstract: A wide-ranging analytical investigation of laminar film condensation is presented. The situation under study is an isothermal vertical plate with steam as the condensing vapor and air as the noncondensable gas. In addition to the noncondensable gas, the analytical model includes interfacial resistance, superheating, free convection due to both temperature and concentration gradients, mass diffusion and thermal diffusion, and variable properties in both the liquid and the gas-vapor regions. Heat-transfer results are obtained for a wide range of parameters including bulk concentration of the noncondensable gas, system pressure level, wall-to-bulk temperature difference, and degree of superheating. It is demonstrated that small bulk concentrations of the noncondensable gas can have a decisive effect on the heat-transfer rate. For instance, for a bulk mass fraction of air equal to 0.5 per cent, reductions in heat transfer of 50 per cent or more are sustained. The influence of the noncondensable gas is accentuated at lower pressure levels. It is shown that the aforementioned reductions in heat transfer are due entirely to the diffusional resistance of the gas-vapor boundary layer. The interfacial resistance is shown to be a second order effect. A similar finding applies to thermal diffusion and diffusion thermo. The effect of superheating, which is very small in the case of a pure vapor, becomes much more significant in the presence of a noncondensable gas. A reference temperature rule is deduced for extending the Nusselt model to variable-property conditions.

362 citations

Journal ArticleDOI
TL;DR: In this paper, heat transfer rates in laminar film condensation on the underside of horizontal and inclined surfaces are predicted by assuming the condensate flow to be the quasi-steady result of a bounded instability.
Abstract: Heat-transfer rates in laminar film condensation on the underside of horizontal and inclined surfaces are predicted by assuming the condensate flow to be the quasi-steady result of a bounded instability. This assumption makes it possible to determine the final shape of the liquid-vapor interface, and thus predict the average heat-transfer coefficient. Measurements of the heat-transfer coefficient obtained by condensing Freon-113 were found to agree quite well with the values predicted by this method. Several distinct regimes of flow in the condensate film were observed. On the underside of horizontal surfaces, the interface is best described as a fully established Taylor instability. At slight angles of inclination there are three regimes of flow. Near the leading edge, the interface is smooth and waveless. Next there is a region of developing waves which are best described as elongated drops or longitudinal ridges. As the ridges grow in amplitude, drops form at the crests and subsequently fall from the surface. beyond the point at which drops first fall, a third regime exists which can be considered to be a fully developed state, independent of distance from the leading edge of the surface. At moderate angles of inclination and up to the vertical, “roll waves” appear a short distance from the leading edge.

91 citations