Corrections to “Selection and Evaluation of Organosilicon Coolants for Direct Immersion Cooling of Electronic Systems”

2013 ◽  
Vol 52 (24) ◽  
pp. 8354-8354
Author(s):  
Pramod Warrier ◽  
Aravind Sathyanarayana ◽  
Sara Bazdar ◽  
Yogendra Joshi ◽  
Amyn S. Teja
Keyword(s):  
Electronic Systems ◽  
Immersion Cooling ◽  
Direct Immersion Cooling ◽  
Direct Immersion

Selection and Evaluation of Organosilicon Coolants for Direct Immersion Cooling of Electronic Systems

2012 ◽  
Vol 51 (31) ◽  
pp. 10517-10523 ◽  
Author(s):  
Pramod Warrier ◽  
Aravind Sathyanarayana ◽  
Sara Bazdar ◽  
Yogendra Joshi ◽  
Amyn S. Teja
Keyword(s):  
Electronic Systems ◽  
Immersion Cooling ◽  
Direct Immersion Cooling ◽  
Direct Immersion

Design and Performance of Novel Low-Profile Heat Sinks Created Through Additive Manufacturing

2016 ◽  
Author(s):  
Pratik KC ◽  
Sangeet Shrestha ◽  
Adarsh Radadia ◽  
Leland Weiss ◽  
Arden Moore
Keyword(s):  
Additive Manufacturing ◽  
Heat Sink ◽  
Heat Sinks ◽  
Two Phase ◽  
Printed Circuit ◽  
Immersion Cooling ◽  
Low Profile ◽  
Direct Immersion Cooling ◽  
Power Densities ◽  
Direct Immersion

Traditional thermal management techniques such as air-cooled plate- and pin-fin heat sinks are today being pushed to their limits by the increasing power densities of computing hardware (power supplies, controllers, processors, and integrated circuits). In comparison, direct immersion cooling within an alternative cooling medium such as commercial dielectric fluids offers the ability to handle high power densities while also accommodating tighter printed circuit board spacing. Together, these attributes are critical to facilitating higher computing densities. However, this type of high density setup also requires that any heat sink present be low profile so as to not obstruct adjacent printed circuit boards. Such a stringent limit on heat sink height can make achieving cooling targets challenging with existing designs. In this work, the performance of several low profile (height less than 6 mm) heat sinks of varying design are evaluated within a carefully controlled direct immersion cooling environment. Commercial copper heat sinks fabricated through conventional manufacturing (CM) approaches serve as baselines for these performance tests. These same heat sink designs are also replicated via additive manufacturing (AM) utilizing a conductive, carbon-filled printable polylactic acid (PLA) composite material. The performance of these AM heat sinks are then compared to the CM heat sinks, with special emphasis on differences in thermal conductivity between the constituent materials. Finally, novel bio-inspired heat sink designs are developed which would be difficult or impossible to achieve using CM approaches. The most promising of these designs were then created using AM and their performance evaluated for comparison. The overall goal of this is to ascertain whether the design and fabrication flexibility offered by AM can facilitate low profile heat sink designs that can meet or exceed the performance of conventional heat sinks even with perceived deficiencies in material properties for AM parts. Experiments were carried out within Novec 7100 dielectric fluid for single-phase natural convection scenarios as well as two-phase subcooled boiling conditions at atmospheric pressure. A custom test rig was constructed consisting of mirror-polished stainless steel plates and polycarbonate viewing ports to allow visual access. A rotating sample stage allows for data to be obtained at varying heat sink orientation angles from 0° to 90°. For two-phase experiments, multi-angle video capture allows for analysis of the two-phase dynamics occurring at the heat sink samples to be visualized and temporally linked to the associated temperature and heat flux data.

Pool Boiling of HFE 7200–C4H4F6O Mixture on Hybrid Micro-Nanostructured Surface

2012 ◽  
Vol 3 (4) ◽  
Author(s):  
Aravind Sathyanarayana ◽  
Pramod Warrier ◽  
Yunhyeok Im ◽  
Yogendra Joshi ◽  
Amyn S. Teja
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Molecular Design ◽  
Pool Boiling ◽  
Dielectric Constants ◽  
Heat Transfer Fluid ◽  
Fluid Mixture ◽  
Immersion Cooling ◽  
Direct Immersion Cooling ◽  
Direct Immersion

Steadily increasing heat dissipation in electronic devices has generated renewed interest in direct immersion cooling. The ideal heat transfer fluid for direct immersion cooling applications should be chemically and thermally stable, and compatible with the electronic components. These constraints have led to the use of Novec fluids and fluroinerts as coolants. Although these fluids are chemically stable and have low dielectric constants, they are plagued by poor thermal properties like low thermal conductivity (about twice that of air) and low specific heat (same as that of air). These factors necessitate the development of new heat transfer fluids with improved heat transfer properties and applicability. C4H4F6O is a new heat transfer fluid which has been identified using computer-aided molecular design (CAMD) and knowledge-based approaches. A mixture of Novec fluid (HFE 7200) with C4H4F6O is evaluated in this study. Pool boiling experiments are performed at saturated condition on a 10 mm × 10 mm silicon test chip with CuO nanostructures on a microgrooved surface, to investigate the thermal performance of this new fluid mixture. The mixture increased the critical heat flux moderately by 8.4% over pure HFE 7200. Additional investigation is necessary before C4H4F6O can be considered for immersion cooling applications.

Novel heat transfer fluids for direct immersion phase change cooling of electronic systems

2012 ◽  
Vol 55 (13-14) ◽  
pp. 3379-3385 ◽  
Author(s):  
Pramod Warrier ◽  
Aravind Sathyanarayana ◽  
Dadasaheb V. Patil ◽  
Stefan France ◽  
Yogendra Joshi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Electronic Systems ◽  
Heat Transfer Fluids ◽  
Direct Immersion

Preservation of Morphological Integrity and Clot Retraction Activity of Human Platelets After Freezing

1964 ◽  
Vol 11 (01) ◽  
pp. 222-229 ◽  
Author(s):  
Isaac Djerassi ◽  
Albert Roy ◽  
Jorge Alvarado ◽  
Keyword(s):  
Dimethyl Sulfoxide ◽  
Liquid Nitrogen ◽  
Human Platelets ◽  
Slow Freezing ◽  
Critical Conditions ◽  
Plasma Medium ◽  
Clot Retraction ◽  
Controlled Freezing ◽  
Direct Immersion

SummaryHuman platelets frozen at −195° C (liquid nitrogen) retain their morphological integrity and ability to promote clot retraction when 5% dimethyl-sulfoxide and 5% dextrose are added to the suspending plasma medium. Slow freezing was more effective than direct immersion in the liquid nitrogen. Although similar results may be achieved with dimethylsulfoxide alone with rigidly controlled freezing rates, the addition of sugars may permit freezing under less critical conditions.Dimethylsulfoxyd und 5% Dextrose dem Plasmamilieu hinzugefügt werden. Das langsame Einfrieren ist effektiver als das direkte Eintauchen in flüssigen Stickstoff. Obschon ähnliche Resultate mit Dimethylsulfoxyd allein unter exakter Kontrolle der Einfrierungsgeschwindig-keit erreicht werden können, erlaubt die Zugabe von Dextrose ein Einfrieren unter weniger kritischen Bedingungen.

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