Design and Testing of a Carbon Foam Based Supercooler for High Heat Flux Cooling in Optoelectronic Packages

2009 ◽  
Author(s):  
Walter W. Yuen ◽  
Jianping Tu ◽  
Wai-Cheong Tam ◽  
Dan Blumenthal
Keyword(s):  
Heat Flux ◽  
Heated Surface ◽  
Local Maximum ◽  
Carbon Foam ◽  
High Heat ◽  
Maximum Temperature ◽  
Transient Temperature ◽  
High Heat Flux ◽  
Periodic Heating ◽  
Heating Region

The feasibility of using carbon foam as a heat sink and heat spreader in optoelectronic packages is assessed. A “supercooler” is designed, fabricated and tested to verify its cooling capability under high heat flux conditions in a typical optoelectronic package. The supercooler uses carbon foam as a primary heat transfer material. Water is soaked into the carbon foam and under evacuated pressure, boiling is initiated under the heating region to provide enhanced cooling. Experiments were conducted for a heat flux of up to 400 W/cm2 deposited over a heating area of 0.5 mm × 5 mm. Two dimensional transient temperature distributions were recorded using a high speed infrared camera. Data were obtained for steady heating, as well as periodic heating with frequency up to 8 hz. Results show that the supercooler is very efficient in dissipating heat away from the heating region. Data obtained under 8 hz periodic heating with a peak power input of 10W, for example, showed that the temperature of the heated surface rises quickly to a local maximum of 15 to 20 °K above the ambient. The heated surface is then cooled uniformly back to a near ambient condition (with a maximum temperature of less than 5 °K above ambient) during the cooling half of the cycle (less than 0.0625 sec after the heating is turned off). The average cooling rate during the cooling period exceeds 170 °K/s. A numerical model, based on COMSOL, is developed to interpret the experimental data and to provide insights on the relevant physics responsible for the rapid cooling. Numerical data are presented to demonstrate how the supercooler can be further improved and adopted for other applications.

Critical Heat Flux Enhancement in Water-Based Nanofluid With Honeycomb Porous Plate on Large Heated Surface

2016 ◽  
Author(s):  
Suazlan Mt Aznam ◽  
Shoji Mori ◽  
Kunito Okuyama
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Heated Surface ◽  
Porous Plate ◽  
High Heat ◽  
High Heat Flux ◽  
Heater Surface ◽  
Solid Structure ◽  
Water Based ◽  
Plain Surface

Heat removal through pool boiling is limited by the phenomena of critical heat flux (CHF). CHF enhancement is vitally important in order to satisfy demand for the cooling technology with high heat flux in In Vessel Retention (IVR). Various surface modifications of the boiling surface, e.g., integrated surface structures and coating of a micro-porous have been proven to effectively enhance the CHF in saturated pool boiling. We have been proposed a novel method of attaching a honeycomb structured porous plate on a considerably large heater surface. Previous results, by the authors in [1] reported that CHF has been enhanced experimentally up to more than approximately twice that of a plain surface (approximately 2.0 to 2.5 MW/m2) with a diameter of 30 mm heated surface. However, it is necessary to demonstrate the method together with infinite heater surface within laboratory scale. It is important that cooling techniques for IVR could be applicable to a large heated surface as well as remove high heat flux. Objective of this study is to investigate the CHF of honeycomb porous plate and metal solid structure in nanofluid boiling or water boiling on a large heated surface. Water-based nanofluid offers good wettability and capillarity. While metal solid structure is installed on honeycomb porous plate to increase the number of vapor jet. Experimental results of honeycomb porous plate and combination of honeycomb porous plate and metal solid structure in water-based nanofluid boiling shows that CHF is increased up to twice [2] and thrice, respectively compared to plain surface in water boiling. To the best of the author’s knowledge, the highest value (3.1 MW/m2) was obtained for a large heated surface having a diameter of 50 mm which is regarded as infinite heated surface. This demonstrates potential for general applicability to have more safety margin in IVR method.

A Highly Efficient Integrated Silicon-Microchannel Cooler for Multi-Module Electronic Microsystems-Model Design, Optimization and Performance Validation

2020 ◽  
pp. 1-38
Author(s):  
Jiejun Wang ◽  
Tao Wang ◽  
Qiuyan Li ◽  
Yiming Li ◽  
Chuangui Wu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Flow Distribution ◽  
Development Trend ◽  
High Heat ◽  
Coolant Flow ◽  
Maximum Temperature ◽  
High Heat Flux ◽  
Highly Efficient ◽  
And Performance ◽  
Performance Validation

Abstract Recently, the development trend of multi-module and multi-function in electronic microsystems makes the ever-increasing heat flux problem more serious. In this study, a highly efficient integrated single-phase microchannel cooler with four heat sources is presented for handling the challenges from both working independently of all electronic modules and the high heat flux. Numerical and experimental study are both conducted. By optimizing the structural design and the fabricated process, the presented microchannel cooler has outstanding cooling performance, which contains desired fluid flow distribution, pressure drop, heat transfer and combination thereof. Results reveals uniform coolant flow dissipates four individual heaters independently, and their maximal temperature difference below 4 °C. Beyond this, high heat flux removal (707.6 W/cm2) is realized with extremely low coolant flow rate (45 ml/min), and the maximum temperature rise is less than 60 °C. This study provides a referable solution for the thermal management of multi-module heat source and high heat flux in compact electronic microsystems.

Cooling of a Heated Surface by Mist Flow

1994 ◽  
Vol 116 (1) ◽  
pp. 167-172 ◽  
Author(s):  
S. L. Lee ◽  
Z. H. Yang ◽  
Y. Hsyua
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Liquid Film ◽  
Heated Surface ◽  
High Heat ◽  
Dynamic Interaction ◽  
High Heat Flux ◽  
Steady Temperature ◽  
Mist Flow ◽  
High Level

Cooling requirements in modern industrial applications, such as the removal of heat from electronic equipments, often demand the simultaneous attainment of a high heat flux and a low and relatively uniform and steady temperature of the heated surface to be cooled. The conventional single-phase convection cooling obviously cannot be expected to function adequately, since the heat flux there is directly proportional to the temperature difference between the heated surface and the surrounding medium. To maintain a high heat flux, the temperature of the heated surface usually must be kept at a high level. An attractive alternative is cooling by a spray, which takes advantage of the significant latent heat of evaporation of the liquid. However, in conventional industrial spray coolings, such as in the case of the cooling tower of a power plant, the temperature of the heated surface usually remains relatively high and is nonuniform and unsteady containing numerous flashy hot spots. In order to optimize the performance of the spray cooling of a heated surface by a mist flow, a clear understanding is required of (1) the dynamic interaction between the droplets and the carrier fluid and (2) the thermal reception of the droplets at the heated surface. It is the dynamic interaction between the phases that is causing the droplets to deposit onto the heated surface. The thermal reception at the heated wall develops mass and heat transfer leading to the mode of cooling of the heated surface. In the present study, an experimental investigation was made of the combination of the dynamic depositional behavior of droplets in a water droplet-air mist flow with the use of a specially designed particle-sizing two-dimensional laser-Doppler anemometer. Also, the heat transfer characteristics at the heated surface were investigated in relation to droplet deposition on the heated surface for wide ranges of droplet size, droplet concentration, mist flow velocity, and heat flux. It was discovered that over a certain suitable range of combination of these parameters, a superbly effective cooling scheme could be established by the evaporation on the outside surface of an ultrathin liquid film. Such a film was formed on the heated surface by the continuous deposition of fine droplets from the mist flow. Under these conditions, the heat flux is primarily related to the evaporation of the ultrathin liquid film on the heated surface and thus depends less on the temperature difference between the heated surf ace and the ambient mist flow. The heated surface is quenched to a low, relatively uniform and steady temperature at a very high level of heat flux. Heat transfer enhancement as high as seven times has been found so far. This effective heat transfer scheme is here termed mist cooling.

Multi-Objective Optimization of Micro Pin-Fin Arrays for Cooling of High Heat Flux Electronics

2015 ◽  
Author(s):  
Sohail R. Reddy ◽  
George S. Dulikravich
Keyword(s):  
Heat Flux ◽  
Cross Section ◽  
High Heat ◽  
Heat Transfer Analysis ◽  
Maximum Temperature ◽  
High Heat Flux ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Pin Fin ◽  
Pin Fin Arrays

The thermal management capability of various candidates of micro-pin fin arrays is investigated. An integrated circuit having a footprint of 4 × 3 mm with micro-pin fin array having circular, airfoil and convex cross-section is considered. The three pin fin cross-sections along with the cooling schemes are optimized to handle a uniform heat flux of 500 W/cm2 applied to the top surface of the electronic chip. A fully three-dimensional, steady-state conjugate heat transfer analysis was performed on each cooling configuration and a constrained multi-objective optimization was carried out for each of the three micro-pin fin shapes to find pin fin designs configurations capable of cooling such high heat fluxes. The design variables were the geometric parameters defining each pin fin cross section, height of the chip and inlet speed of the coolant. The two simultaneous objectives were to minimize maximum temperature and pressure drop (pumping power), while keeping the maximum temperature below 85°C. A response surface was constructed for each objective function and was coupled with a genetic algorithm to arrive at a Pareto frontier of the best trade-off solutions. Stress-deformation analysis incorporating the hydrodynamic and thermal loads was performed on each of the three optimized configurations. The maximum displacement was found to be on the nano-level, and the Von-Mises stress for each configuration was found to be significantly below the yield strength of Silicon.

The Simulation of Heat Pipe Evaporator in Concentration Solar Cell

2010 ◽  
Vol 44-47 ◽  
pp. 1207-1212 ◽  
Author(s):  
Zi Long Wang ◽  
Hua Zhang ◽  
Hai Tao Zhang
Keyword(s):  
Heat Flux ◽  
Solar Cell ◽  
Heat Pipe ◽  
Saturation Temperature ◽  
High Heat ◽  
Maximum Temperature ◽  
Working Fluid ◽  
High Heat Flux ◽  
Two Phase ◽  
Solar Cell Performance

Considering the problem of the concentrating solar cell efficiency restricted by the temperature. The closed two-phase thermosyphon was used to dissipation heat in concentrating solar cell at high heat flux, which adopted water as the working fluid. The temperature distribution of evaporator had significant effect on solar cell performance and heat pipe efficiency. A numerical simulation model of evaporator was established by FLUENT. During the computing process, the heat flux, filling ratio of liquid and saturation temperature were taken into account. It was found that the maximum temperature of evaporator was less than 85°C, when the solar cell operated in 140 to 180 suns, in the conditions of evaporator size (Length×Width×Height, 100×100×30 mm), the optimum charging ratio of liquid is between 27%～30%. The smaller saturation temperature would bring the better heat transfer characters.

Two-Phase Cooling Characteristics of Mono-Dispersed Droplets Impacted on a Heated Surface

2011 ◽  
Author(s):  
S. R. Mahmoudi ◽  
K. Adamiak ◽  
G. S. P. Castle
Keyword(s):  
Heat Flux ◽  
Impact Velocity ◽  
Heated Surface ◽  
Experimental Studies ◽  
Volumetric Flow Rate ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase ◽  
Mass Fluxes ◽  
The Impact

Droplet impact cooling has been shown to be a promising method for high heat flux removal applications. Recent experimental studies have revealed that even higher heat transfer at low mass fluxes and low Weber number can be achieved with only few degrees of superheat. In the present work, mono-dispersed droplet cooling of a horizontal upward facing heated surface was investigated at low Weber numbers. The impact velocity and frequency of free falling stream of droplets were varied dependently through changing the gap between the heated surface and tip of different capillaries and variation of volumetric flow rate (0.5–4.7 cc/min).The range of impact velocity and droplet frequency was ranged between 0.28 to 1.3 m/s and 0.5 Hz to 5 Hz, respectively using different capillaries size between 17g to 22g. The coolant was 25°C deionized water and all the experiments were performed at atmospheric pressure. The time-averaged two-phase characteristic curves were obtained up to Critical Heat Flux (CHF)-regime. Through the extensive set of experiments, two separate correlations are proposed to predict the average CHFs based on the Weber between 3<We<10, 10<We<100 and Strouhal number ranged and 6.35×10−3<St<3.88×10−2 1.81×10−3<St<3.86×10−2, respectively. The correlation predicts the average CHFs with absolute errors less than 20% and 25%, respectively.

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