Effect of Fin and Insert on the Performance Characteristics of Open Loop Pulsating Heat Pipe (OLPHP)

Homogenous dispersing of nanoparticles in a base fluid is an excellent way to increase the thermal performance of heat transfer devices especially Heat Pipes (HPs). As a wickless, cheap and efficient heat pipe, Pulsating Heat Pipes (PHPs) are important candidates for thermal application considerations. In the present research an Open Loop Pulsating Heat Pipe (OLPHP) is fabricated and tested experimentally. The effects of working fluid namely, water, Silica Coated ferrofluid (SC ferrofluid), and ferrofluid without surface coating of nanoparticles (ferrofluid), charging ratio, heat input, and application of magnetic field on the overall thermal performance of the OLPHPs are investigated. Experimental results show that ferrofluid has better heat transport capability relative to SC ferrofluid. Furthermore, application of magnetic field improves the heat transfer performance of OLPHPs charged with both ferrofluids.

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Thermal Performance of an Open Loop Pulsating Heat Pipe With Ferrofluid (Magnetic Nano-Fluid)

ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2012-75070 ◽

2012 ◽

Author(s):

Mehdi Taslimifar ◽

Maziar Mohammadi ◽

Mohammad Hassan Saidi ◽

Hossein Afshin ◽

Mohammad Behshad Shafii ◽

...

Keyword(s):

Thermal Resistance ◽

Heat Pipe ◽

Thermal Performance ◽

Inclination Angle ◽

Open Loop ◽

Working Fluid ◽

Pulsating Heat Pipe ◽

Degree Relative ◽

Nano Fluid ◽

Transfer Capability

In the present research an experimental investigation is performed to explore the effects of working fluid, heat input, ferrofluid concentration, magnets location, and inclination angle on the thermal performance of an Open Loop Pulsating Heat Pipe (OLPHP). Obtained results show that using ferrofluid can improve the thermal performance and applying a magnetic field on the water based ferrofluid decreases the thermal resistance. It shows that at an inclination angle of the OLPHP to be zero, the thermal performance of the present OLPHP reduces. Best heat transfer capability was achieved at 67.5 degree relative to horizontal axis for all of working fluids. Variation of the magnets location leads to a different thermal resistance in the OLPHP charged with ferrofluid.

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Experimental Characterization of an Open Loop Pulsating Heat Pipe Cooler

ASME 2014 12th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2014-22047 ◽

2014 ◽

Cited By ~ 2

Author(s):

Daniele Torresin ◽

Mathieu Habert ◽

Francesco Agostini ◽

Bruno Agostini ◽

Violette Mounier

Keyword(s):

Heat Pipe ◽

Heat Load ◽

Low Cost ◽

Fluid Pressure ◽

Electronics Cooling ◽

Open Loop ◽

Air Cooling ◽

Pulsating Heat Pipe ◽

Two Phase ◽

Term Operation

Pulsating heat pipes (PHP) have emerged in the last years as suitable cooling devices for dissipating the high heat loads generated by electronic devices since they allow to extend the applicability of air cooling in area nowadays covered by water cooling. Two-phase cooling technologies based on the two phase pulsating heat pipe principle are promising solutions because, being entirely passive they can comply with long term operation without maintenance. The main advantage of a PHP compared to conventional thermosyphon technologies for electronics cooling is that a PHP is orientation independent. The authors has developed a novel, compact, and low cost PHP based on automotive technology. The present paper presents the experimental results of an air cooled open loop pulsating heat pipe with optimized manifold design to minimize fluid pressure drops in the fluid turns. The effect of several parameters including filling ratio and heat load are presented. Tests have been done with the refrigerant fluid R245fa in vertical and horizontal orientations. The measurements showed a maximum thermal resistance ranging between 40 and 48 K/kW in vertical and horizontal position respectively for a heat load of 2 kW and air temperature of 20 °C.

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Thermal performance of an open loop closed end pulsating heat pipe

Heat and Mass Transfer ◽

10.1007/s00231-011-0882-9 ◽

2011 ◽

Vol 48 (2) ◽

pp. 259-265 ◽

Cited By ~ 18

Author(s):

Manabendra Saha ◽

C. M. Feroz ◽

F. Ahmed ◽

T. Mujib

Keyword(s):

Heat Pipe ◽

Thermal Performance ◽

Open Loop ◽

Pulsating Heat Pipe

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Characteristics of an Open Loop Pulsating Heat Pipe

10.4271/2004-01-2509 ◽

2004 ◽

Cited By ~ 9

Author(s):

Roger R. Riehl

Keyword(s):

Heat Pipe ◽

Open Loop ◽

Pulsating Heat Pipe

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An Open Loop Pulsating Heat Pipe for Integrated Electronic Cooling Applications

Volume 3: Gas Turbine Heat Transfer; Transport Phenomena in Materials Processing and Manufacturing; Heat Transfer in Electronic Equipment; Symposium in Honor of Professor Richard Goldstein; Symposium in Honor of Prof. Spalding; Symposium in Honor of Prof. Arthur E. Bergles ◽

10.1115/ht2013-17009 ◽

2013 ◽

Author(s):

Daniel Kearney ◽

Justin Griffin

Keyword(s):

Heat Pipe ◽

Open Loop ◽

Organic Substrate ◽

Heat Fluxes ◽

Electronic Cooling ◽

Electronic Systems ◽

Pulsating Heat Pipe ◽

Fill Ratio ◽

Lower Heat ◽

Increasing Trends

Increasing trends towards integrated power electronic systems demand advancements in novel, efficient thermal management solutions to cope with the increasing the power density. This paper investigates the performance of a novel open loop pulsating heat pipe embedded in an FR4 organic substrate. The heat pipe and is comprised of 26 parallel minichannels with 13 turns, an average hydraulic diameter of 1.9mm and maximum surface roughness of 2.5μm. The bulk thermal performance of three saturated working fluids — Novec 649, Novec 7200 and Ethanol (99.8%) — is investigated in terms of fill ratio, three angles of orientation, and applied heat fluxes ranging from 0.4 to 2.5W/cm2 at sub-ambient pressures. Novec 649 achieved quasi-stable pulsations at lower heat fluxes due to lower (dp/dT)sat. In addition, the dielectric Novec 649 fluid showed significant potential for integrated heat spreading applications demonstrating heat transfer of up to 176W and thermal resistances as low as 0.25°C/W for a filling ratio of 30% — a 16× improvement to that of a standard dry FR4 substrate.

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