Microelectromechanical System-Based Evaporative Thermal Management of High Heat Flux Electronics

2005 ◽  
Vol 127 (1) ◽  
pp. 66-75 ◽  
Author(s):  
Cristina H. Amon ◽  
S.-C. Yao ◽  
C.-F. Wu ◽  
C.-C. Hsieh
Keyword(s):  
Microelectromechanical Systems ◽  
Surface Texturing ◽  
Jet Impingement ◽  
Heat Fluxes ◽  
Future Research ◽  
Dielectric Fluid ◽  
Practical Implementation ◽  
High Heat Flux ◽  
Droplet Impingement ◽  
Impingement Cooling

This paper describes the development of embedded droplet impingement for integrated cooling of electronics (EDIFICE), which seeks to develop an integrated droplet impingement cooling device for removing chip heat fluxes over 100W/cm2, employing latent heat of vaporization of dielectric fluids. Micromanufacturing and microelectromechanical systems are used as enabling technologies for developing innovative cooling schemes. Microspray nozzles are fabricated to produce 50–100 μm droplets coupled with surface texturing on the backside of the chip to promote droplet spreading and effective evaporation. This paper examines jet impingement cooling of EDIFICE with a dielectric coolant and the influence of fluid properties, microspray characteristics, and surface evaporation. The development of micronozzles and microstructured surface texturing is discussed. Results of a prototype testing of swiss-roll swirl nozzles with dielectric fluid HFE-7200 on a notebook PC are presented. This paper also outlines the challenges to practical implementation and future research needs.

MEMS-Based Spatial and Temporal Thermal Management of High Heat Flux Electronics

2003 ◽  
Author(s):  
Cristina H. Amon ◽  
S. C. Yao
Keyword(s):  
Thermal Management ◽  
Surface Texturing ◽  
Jet Impingement ◽  
Heat Fluxes ◽  
Dielectric Fluid ◽  
Practical Implementation ◽  
High Heat Flux ◽  
Droplet Impingement ◽  
Micro Manufacturing ◽  
Impingement Cooling

This presentation describes the development of EDIFICE: Embedded Droplet Impingement For Integrated Cooling of Electronics. The EDIFICE project seeks to develop an integrated droplet impingement cooling device for removing chip heat fluxes over 100 W/cm2, employing latent heat of vaporization of dielectric fluids. Micro-manufacturing and MEMS (Micro Electro-Mechanical Systems) will be discussed as enabling technologies for innovative cooling schemes recently proposed. Micro-spray nozzles are fabricated to produce 50–100 micron droplets coupled with surface texturing on the backside of the chip to promote droplet spreading and effective evaporation. A novel feature to enable adaptive on-demand cooling is MEMS sensing (on-chip temperature, remote IR temperature and ultrasonic dielectric film thickness) and MEMS actuation. EDIFICE is integrated within the electronics package and fabricated using advanced micro-manufacturing technologies (e.g., Deep Reactive lon Etching (DRIE) and CMOS CMU-MEMS). The development of EDIFICE involves modeling, CFD simulations, and physical experimentation on test beds. This lecture will then examine jet impingement cooling of EDIFICE with a dielectric coolant and the influence of fluid properties, micro spray characteristics, and surface evaporation. The development of micro nozzles, micro-structured surface texturing, and the system integration of the evaporator is discussed. Results of a prototype testing of swirl nozzles with dielectric fluid HFE-7200 on a notebook PC are presented. This paper also reviews liquid and evaporative cooling research applied to thermal management of electronics. It outlines the challenges to practical implementation and future research needs.

An Experimental Study of a Multi-Device Jet Impingement Cooler With Phase Change Using HFE-7100

2013 ◽  
Author(s):  
Shailesh N. Joshi ◽  
Matthew J. Rau ◽  
Ercan M. Dede ◽  
Suresh V. Garimella
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Phase Change ◽  
Jet Impingement ◽  
Heat Fluxes ◽  
Orifice Diameter ◽  
Working Fluid ◽  
Dielectric Fluid ◽  
Automotive Electronics ◽  
Impingement Cooling

Jet impingement cooling with phase change has shown the potential to meet the increased cooling capacity demands of high-power-density (of order 100 W/cm2) automotive electronics components. In addition to improved heat transfer, phase change cooling has the potential benefit of providing a relatively isothermal cooling surface. In the present study, two-phase jet impingement cooling of multiple electronic devices is investigated, where the fluorinated dielectric fluid HFE-7100 is used as the working fluid. Four different types of jet arrays, namely, a single round jet with orifice diameter of 3.75 mm, and three different 5 × 5 arrays of round jets with orifice diameters of 0.5 mm, 0.6 mm and 0.75 mm, were tested and compared for both heat transfer and pressure drop. The experimental Reynolds number at the orifice ranged from 1860 to 9300. The results show that for the same orifice pressure drop, the single jet reached CHF at approximately 60 W/cm2, while the 5 × 5 array (d = 0.75 mm) safely reached heat fluxes exceeding 65 W/cm2 without reaching CHF. Additionally, the experimental results show that the multi-device cooler design causes an unintended rise in pressure inside the test section and a subsequent increase in sub-cooling from 10 K to 23.3 K.

Experimental and Theoretical Studies of Mist Jet Impingement Cooling

1996 ◽  
Vol 118 (2) ◽  
pp. 343-349 ◽  
Author(s):  
K. M. Graham ◽  
S. Ramadhyani
Keyword(s):  
Experimental Data ◽  
Jet Impingement ◽  
Target Surface ◽  
Heat Fluxes ◽  
Heat Sources ◽  
Impingement Cooling ◽  
Jet Cooling ◽  
Air Jet ◽  
Model Predictions ◽  
Experimental And Theoretical Studies

Experimental data and analytical predictions for air/liquid mist jet cooling of small heat sources are presented. The mist jet was created using a coaxial jet atomizer, with a liquid jet of diameter 190 μm located on the axis of an annular air jet of diameter 2 mm. The impingement surface was a square of side 6.35 mm. Experimental data were obtained with mists of both methanol and water. Surface-averaged heat fluxes as high as 60 W/cm2 could be dissipated with the methanol/air mist while maintaining the target surface below 70°C. With the water/air mist, a heat flux of 60 W/cm2 could be dissipated with the target surface at 80°C. Major trends in the data and model predictions have been explained in terms of the underlying hydrodynamic and heat transfer phenomena.

Novel PCM and Jet Impingement Based Cooling Scheme for High Density Transient Heat Loads

2010 ◽  
Author(s):  
Pritish R. Parida ◽  
Srinath V. Ekkad ◽  
Khai Ngo
Keyword(s):  
Phase Change Materials ◽  
High Efficiency ◽  
Cooling System ◽  
Jet Impingement ◽  
High Heat ◽  
High Heat Flux ◽  
Impingement Cooling ◽  
Small Areas ◽  
High Heat Transfer ◽  
Heat Loads

Breakthroughs in the recent cutting-edge technologies have become increasingly dependent on the ability to safely dissipate large amount of heat from small areas. Improvements in cooling techniques are therefore required to avoid unacceptable temperature rise and at the same time maintain high efficiency. Jet impingement is one such cooling scheme which has been widely used to dissipate transient and steady concentrated heat loads. With constantly increasing transient cooling needs, conventional pin-fin cooling and conventional jet impingement cooling are not meeting the requirements. Considerable improvements are therefore required to meet such stringent requirements without any significant changes in the cooling system. A combined cooling scheme based on jet impingement and phase change materials (PCMs) is presented as one such alternative to existing cooling systems. A high heat storage capability of PCMs in combination with a high heat transfer rates from impingement cooling can help overcome the existing heat distribution and transient cooling problems in high heat flux dissipating devices. Preliminary conjugate CFD simulations show promising results. Additionally, experimental validation of the simulation predictions has also been performed. A reasonably good agreement was found between the predictions and experiments.

MEMS Enabled Micro Spray Cooling System for Thermal Control of Electronic Chips

2001 ◽  
Author(s):  
S. C. Yao ◽  
C. H. Amon ◽  
K. Gabriel ◽  
P. Kumta ◽  
J. Y. Murthy ◽  
...  
Keyword(s):  
Cooling System ◽  
Surface Texturing ◽  
Thermal Control ◽  
Spray Cooling ◽  
Heat Fluxes ◽  
System Level ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Droplet Impingement ◽  
Dielectric Fluids

Abstract Liquid cooling of electronic devices becomes necessary when the chip-level heat fluxes increase and traditional air cooling encounters ever-increasing difficulties. From all the liquid cooling processes, spray cooling appears more successful due to its high critical heat flux, relatively low liquid flow rates, highly controllable, and the non-existence of boiling incipient hysterisis. This paper describes the development of the EDIFICE project (Embedded Droplet Impingement For Integrated Cooling of Electronics), which seeks to develop an integrated droplet impingement cooling device for removing chip heat fluxes in the range 50–100 W/cm2, employing latent heat of vaporization of dielectric fluids. Micro-spray nozzles are fabricated on silicon using MEMS technology to produce 100 micron droplets with odd shaped nozzles and swirling nozzles. The effects of shape, size, type of fluid, and swirling are tested and discussed. Spray heat transfer on silicon surfaces is studied with various surface texturing on the backside of the chip to promote spreading and evaporation of cold fluids as well as at heated conditions. The effects of configuration and fluids are revealed. Numerical modeling is used to study preliminary designs at both the device and system level. The paper describes progress made in the development of the EDIFICE device.

Heat Transfer by a Rotating Liquid Jet Impingement Cooling System

2018 ◽  
Author(s):  
Qi Lu ◽  
Siva Parameswaran ◽  
Beibei Ren
Keyword(s):  
Heat Flux ◽  
Cfd Simulation ◽  
Cooling System ◽  
Automatic Transmission ◽  
Jet Impingement ◽  
High Heat ◽  
Liquid Jet ◽  
High Heat Flux ◽  
Impingement Cooling ◽  
Commercial Code

The circular, liquid jet impingement provides a convenient way of cooling surfaces. To effectively cool the devices inside the electric vehicle, a rotating jet impingement cooling system is designed to evaluate the potential of the jet impingement for high heat flux removal. The liquid used for jet impingement is automatic transmission fluid. The jet impingement system consists of a rotating pipe with two nozzles and a cylindrical ring which is attached to the heat source. To reduce the computational loads, first, the CFD simulation for a laminar flow inside the pipe is carried out to estimate the flow velocities at the nozzle exits. Then, the rotating jet impingement cooling of a cylinder with a uniform surface temperature is investigated numerically for stable, unsubmerged, uniform velocity, single phase laminar jets. The numerical simulation using the commercial code is performed to determine the heat flux removal performance over the cylindrical surface. The numerical results are compared with the empirical formula and experimental measurements from the literature. Furthermore, the effects of the Reynolds number and pipe rotation on the jet impingement cooling performance are also investigated.

History, Advances, and Challenges in Liquid Flow and Flow Boiling Heat Transfer in Microchannels: A Critical Review

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Liquid Flow ◽  
Heat Exchangers ◽  
Single Phase ◽  
Heat Dissipation ◽  
Flow Boiling ◽  
Thermal Control ◽  
Future Research ◽  
Practical Implementation ◽  
High Heat Flux

As the scale of devices becomes small, thermal control and heat dissipation from these devices can be effectively accomplished through the implementation of microchannel passages. The small passages provide a high surface area to volume ratio that enables higher heat transfer rates. High performance microchannel heat exchangers are also attractive in applications where space and/or weight constraints dictate the size of a heat exchanger or where performance enhancement is desired. This survey article provides a historical perspective of the progress made in understanding the underlying mechanisms in single-phase liquid flow and two-phase flow boiling processes and their use in high heat flux removal applications. Future research directions for (i) further enhancing the single-phase heat transfer performance and (ii) enabling practical implementation of flow boiling in microchannel heat exchangers are outlined.

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