Ultra-Cooling Heat Transfer Characteristics Using Cryogenic Micro-Solid Nitrogen Spray

2012 ◽  
Author(s):  
U. Oh ◽  
Jun Ishimoto ◽  
Naoki Harada ◽  
Daisuke Tan
Keyword(s):  
Heat Transfer ◽  
Heated Surface ◽  
Spray Cooling ◽  
High Heat ◽  
Heat Transfer Process ◽  
Solid Particles ◽  
High Heat Flux ◽  
Heat Transfer Characteristics ◽  
Solid Nitrogen ◽  
New Type

The fundamental characteristics of heat transfer and cooling performance of micro-solid nitrogen particulate spray impinging on a heated substrate were numerically investigated and experimentally measured by a new type of integrated computational-experimental technique. The employed CFD based on the Euler-Lagrange model is focused on the cryogenic spray behavior of atomized particulate micro-solid nitrogen and also on its ultra-high heat flux cooling characteristics. Based on the numerically predicted performance, a new type of cryogenic spray cooling technique for application to a ultra-high heat power density device was developed. In the present integrated computation, it is clarified that the cryogenic micro-solid spray cooling characteristics are affected by several factors of the heat transfer process of micro-solid spray which impinges on heated surface as well as by atomization behavior of micro-solid particles.

Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point

2019 ◽  
Author(s):  
Ganesh Guggilla ◽  
Arvind Pattamatta ◽  
Ramesh Narayanaswamy
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Heated Surface ◽  
Electronics Cooling ◽  
Spray Cooling ◽  
High Heat ◽  
Heat Fluxes ◽  
Air Cooling ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract Due to the advancements in computing services such as machine learning and artificial intelligence, high-performance computing systems are needed. Consequently, the increase in electron chip density results in high heat fluxes and required sufficient thermal management to maintain the servers. In recent times, the liquid cooling techniques become prominent over air cooling as it has significant advantages. Spray cooling is one such efficient cooling process which can be implemented in electronics cooling. To enhance the knowledge of the process, detailed studies of fundamental mechanisms involved in spray cooling such as single droplet and multiple droplet interactions are required. The present work focuses on the study of a train of droplets impinging over a heated surface using FC-72 liquid. The surface temperature is chosen as a parameter, and the Dynamic Leidenfrost point (DLP) for the present impact conditions is identified. Spread hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.

Phenomenon and Mechanism of Spray Cooling on Nanowire Arrayed and Hybrid Micro/Nanostructured Surfaces

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Jian-nan Chen ◽  
Rui-na Xu ◽  
Zhen Zhang ◽  
Xue Chen ◽  
Xiao-long Ouyang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
High Speed ◽  
Spray Cooling ◽  
High Heat ◽  
High Heat Flux ◽  
Transfer Enhancement ◽  
Nanostructured Surfaces ◽  
New Energy ◽  
Dry Out

Enhancing spray cooling with surface structures is a common, effective approach for high heat flux thermal management to guarantee the reliability of many high-power, high-speed electronics and to improve the efficiency of new energy systems. However, the fundamental heat transfer enhancement mechanisms are not well understood especially for nanostructures. Here, we fabricated six groups of nanowire arrayed surfaces with various structures and sizes that show for the first time how these nanostructures enhance the spray cooling by improving the surface wettability and the liquid transport to quickly rewet the surface and avoid dry out. These insights into the nanostructure spray cooling heat transfer enhancement mechanisms are combined with microstructure heat transfer mechanism in integrated microstructure and nanostructure hybrid surface that further enhances the spray cooling heat transfer.

High heat flux flow boiling in silicon multi-microchannels – Part I: Heat transfer characteristics of refrigerant R236fa

2008 ◽  
Vol 51 (21-22) ◽  
pp. 5400-5414 ◽  
Author(s):  
Bruno Agostini ◽  
John Richard Thome ◽  
Matteo Fabbri ◽  
Bruno Michel ◽  
Daniele Calmi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Heat Transfer Characteristics ◽  
Flux Flow ◽  
Transfer Characteristics

Experimental Study on Heat Transfer of Fuel-Particle Mixtures in a Vertical Tube at Supercritical Pressure

2013 ◽  
Author(s):  
Xiao-Yu Wu ◽  
Dan Huang ◽  
Wei Li ◽  
Guo-Qiang Xu ◽  
Zhi Tao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Cooling System ◽  
High Heat ◽  
Vertical Tube ◽  
Solid Particles ◽  
Fuel Particle ◽  
High Heat Flux ◽  
Step Method ◽  
Working Pressure

Regenerative cooling system is thought to be an effective and practical solution to better thermal management for high heat flux applications. In this paper, we examined the effects of solid particles mixed with fuels on the heat transfer performances of supercritical fuel coolant. Two-step method was applied to prepare Fe3O4-kerosene fluids. Experiments were carried out to study the heat transfer characteristics of fuel-particle mixtures flowing in a vertical tube at supercritical pressures. Results show that there are three different heat transfer mechanisms at the in-, mid- and ex-sections along the tube; increasing the flow rate or the working pressure could enhance the heat transfer performances, yet higher heat flux leads to poorer heat transfer performances. Besides, the addition of solid particles deteriorates the heat transfer performances of the fuel coolant through the modification of inner wall surfaces. As the particle content increases, the heat transfer performance becomes worse.

Correlation Between Behaviors of the Vapor Bubbles and the Characteristics of the Heat Transfer Over the Heated Surface on MEB

2013 ◽  
Author(s):  
Takahito Saiki ◽  
Tomohiko Osawa ◽  
Ichiro Ueno ◽  
Chungpyo Hong
Keyword(s):  
Heat Transfer ◽  
Vapor Bubble ◽  
High Speed ◽  
Heated Surface ◽  
High Heat ◽  
Frame Rate ◽  
High Heat Flux ◽  
Heated Plate ◽  
Thin Wire ◽  
Vapor Bubbles

A series of experiments on subcooled pool boiling on a plate and on a thin wire are carried out. We focus on the condensation and collapse processes of vapor bubbles generated on the heated surface. We find the different patterns of the vapor bubble behaviors resulting in the emission of the microbubbles around the heated plate and the thin wire by employing high-speed observation with frame rate up to 150,000 frame per second (fps). From the experimental results, we provide a physical explanation on the correlation between the behavior of the vapor bubble at a high heat flux and the heat transfer characteristics. We propose this simple core-periphery model as a qualitative model for understanding the generation of the MEB.

Thermomechanical Resist Removal-Cleaning System Using Cryogenic Micro-Slush Jet

2012 ◽  
Vol 187 ◽  
pp. 145-148 ◽  
Author(s):  
Jun Ishimoto ◽  
Daisuke Tan ◽  
Hiroto Ohtake ◽  
Seiji Samukawa
Keyword(s):  
High Speed ◽  
High Heat ◽  
Present System ◽  
High Heat Flux ◽  
Subcooled Liquid ◽  
Ultrasonic Atomization ◽  
Cleaning System ◽  
Solid Nitrogen ◽  
High Speed Collision ◽  
New Type

The fundamental characteristics of the resist removal-cleaning system using cryogenic micro-solid nitrogen spray flow were investigated by a new type of integrated measurement technique. The present system utilizes the micro-solid nitrogen (SN2) which consists of the fine solid nitrogen particle produced by the high-speed collision of subcooled liquid nitrogen and the cryogenic gaseous helium (cryogen). According to present study, the effect of ultra-high heat flux cooling on the resist removal performance due to the rapid thermal contraction of resist material is clarified in detail. Furthermore, the effect of ultrasonic atomization of micro-solid nitrogen on ultra-clean performance of the wafer is newly founded.

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