Multi-Nozzle Spray Cooling in a Closed Loop

2011 ◽  
Author(s):  
Lanchao Lin ◽  
Quinn Leland
Keyword(s):  
Thermal Performance ◽  
Closed Loop ◽  
Target Surface ◽  
Spray Cooling ◽  
High Heat ◽  
High Heat Flux ◽  
Gear Pump ◽  
Two Phase ◽  
Power Sources ◽  
Phase Loop

A closed two-phase loop system was developed that combined with a multi-nozzle spray cooling unit for the cooling of high heat flux power sources. The fluid circulation was sustained by a magnetic gear pump operating with an ejector pump unit. The motive flow of the ejector shared the pumping liquid flow with the multi-nozzle spray. The use of the ejector stabilized the circulation of the two-phase flow. A multi-nozzle plate with 48 miniature nozzles was designed to generate an array of 4×12 sprays. A closed loop spray cooling experimental setup with a cooling area of 19.3 cm2 was built. The spray nozzle to target distance was 10 mm. Water and FC-72 were used as the working fluids. Spray cooling experiments were performed in three orientations of the spray target surface, namely (a) horizontal facing upward, (b) vertical, and (c) horizontal facing downward. The thermal performance of the horizontal facing downward surface was the best. A comparison with the thermal performance data for a smaller cooling surface area of 2.0 cm2 was made.

Multi-nozzle spray cooling for high heat flux applications in a closed loop system

2013 ◽  
Vol 54 (2) ◽  
pp. 372-379 ◽  
Author(s):  
Y.B. Tan ◽  
J.L. Xie ◽  
F. Duan ◽  
T.N. Wong ◽  
K.C. Toh ◽  
...  
Keyword(s):  
Heat Flux ◽  
Closed Loop ◽  
Spray Cooling ◽  
High Heat ◽  
Loop System ◽  
High Heat Flux ◽  
Closed Loop System

scholarly journals Thermal Transport of High Heat Flux Two-phase Closed Loop Thermosyphon

2014 ◽  
Vol 49 (4) ◽  
pp. 539-546
Author(s):  
Yoshiaki Higuchi ◽  
Katsuya Fukuda ◽  
Qiusheng Liu
Keyword(s):  
Heat Flux ◽  
Thermal Transport ◽  
Closed Loop ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase

Two-Phase Spray Cooling With Water/2-Propanol Binary Mixture: Investigation of Mass Diffusion Resistance

2016 ◽  
Author(s):  
Sai Sujith Obuladinne ◽  
Huseyin Bostanci
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
Spray Cooling ◽  
High Heat ◽  
Working Fluid ◽  
High Heat Flux ◽  
Two Phase ◽  
High Heat Transfer

Two-phase spray cooling has been an emerging thermal management technique offering high heat transfer coefficients (HTCs) and critical heat flux (CHF) levels, near-uniform surface temperatures, and efficient coolant usage that enables to design of compact and lightweight systems. Due to these capabilities, spray cooling is a promising approach for high heat flux applications in computing, power electronics, and optics. The two-phase spray cooling inherently depends on saturation temperature-pressure relationships of the working fluid to take advantage of high heat transfer rates associated with liquid-vapor phase change. When a certain application requires strict temperature and/or pressure conditions, thermophysical properties of the working fluid play a critical role in attaining proper efficiency, reliability, or packaging structure. However, some of the commonly used working fluids today, including refrigerants and dielectric liquids, have relatively poor properties and heat transfer performance. In such cases, utilizing binary mixtures to tune working fluid properties becomes an alternative approach. This study aimed to conduct an initial investigation on the spray cooling characteristics of practically important binary mixtures and demonstrate their capability for challenging high heat flux applications. The working fluid, water/2-propanol binary mixture at various concentration levels, specifically at x1 (liquid mass fraction of 2-proponal in water) of 0.0 (pure water), 0.25, 0.50, 0.879 (azeotropic mixture) and 1.0, represented both non-azeotropic and azeotropic cases. Tests were performed on a closed loop spray cooling system using a pressure atomized spray nozzle with a constant liquid flow rate at corresponding 20°C subcooling conditions and 1 Atm pressure. A copper test section measuring 10 mm × 10 mm × 2 mm with a plain, smooth surface simulated high heat flux source. Experimental procedure involved controlling the heat flux in increasing steps, and recording the steady-state temperatures to obtain cooling curves in the form of surface superheat vs heat flux. The obtained results showed that pure water (x1 = 0.0) and 2-propanol (x1 = 1.0) provide the highest and lowest heat transfer performance, respectively. At a given heat flux level, the HTC values indicated strong dependence on x1, where the HTCs depress proportional to the concentration difference between the liquid and vapor phases. The CHF values sharply decreased at x1≥ 0.25.

Thermal Control Utilizing an Electrohydrodynamic Conduction Pump in a Two-Phase Loop With High Heat Flux Source

2007 ◽  
Vol 129 (11) ◽  
pp. 1576-1583 ◽  
Author(s):  
Seong-II Jeong ◽  
Jeffrey Didion
Keyword(s):  
Heat Flux ◽  
Electric Field ◽  
Thermal Control ◽  
High Heat ◽  
High Heat Flux ◽  
Recombination Reaction ◽  
Two Phase ◽  
New Device ◽  
Dielectric Fluids ◽  
Phase Loop

The electric field applied in dielectric fluids causes an imbalance in the dissociation-recombination reaction generating free space charges. The generated charges are redistributed by the applied electric field, resulting in the heterocharge layers in the vicinity of the electrodes. Proper design of the electrodes generates net axial flow motion pumping the fluid. The electrohydrodynamic (EHD) conduction pump is a new device that pumps dielectric fluids utilizing heterocharge layers formed by imposition of electrostatic fields. This paper experimentally evaluates the performance of a two-phase (liquid-vapor) breadboard thermal control loop consisting of an EHD conduction pump, condenser, preheater, evaporator, transport lines, and reservoir (accumulator). This study is performed to address the feasibility of the EHD two-phase loop for thermal control of a laser equipment with high heat flux source. The generated pressure head and the maximum applicable heat flux are experimentally determined at various applied voltages and sink temperatures. Recovery from the evaporator dryout condition by increasing the applied voltage to the pump is also demonstrated. The performance of the EHD conduction pump in this study confirms that the EHD conduction pump can be used as a stand-alone system for high heat flux thermal control.

Spray Cooling for Time Resolved Emission Measurements of ICs

2004 ◽  
Author(s):  
Rama R. Goruganthu ◽  
David Bethke ◽  
Shawn McBride ◽  
Tom Crawford ◽  
Jonathan Frank ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Flip Chip ◽  
Cooling System ◽  
Spray Cooling ◽  
Junction Temperature ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
High Heat Flux ◽  
Time Resolved

Abstract Spray cooling is implemented on an engineering tool for Time Resolved Emission measurements using a silicon solid immersion lens to achieve high spatial resolution and for probing high heat flux devices. Thermal performance is characterized using a thermal test vehicle consisting of a 4x3 array of cells each with a heater element and a thermal diode to monitor the temperature within the cell. The flip-chip packaged TTV is operated to achieve uniform heat flux across the die. The temperature distribution across the die is measured on the 4x3 grid of the die for various heat loads up to 180 W with corresponding heat flux of 204 W/cm2. Using water as coolant the maximum temperature differential across the die was about 30 °C while keeping the maximum junction temperature below 95 °C and at a heat flux of 200 W/cm2. Details of the thermal performance of spray cooling system as a function of flow rate, coolant

Reliable MOSFET operation using two-phase microfluidics in the presence of high heat flux transients

2011 ◽  
Vol 21 (10) ◽  
pp. 105002 ◽  
Author(s):  
Shiv Govind Singh ◽  
Amit Agrawal ◽  
Siddhartha P Duttagupta
Keyword(s):  
Heat Flux ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase
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