Numerical study of liquid nitrogen based pulsating heat pipe for cooling superconductors

A pulsating heat pipe (PHP), also known as an oscillating heat pipe (OHP), is a passive thermal transport device which consists of a single meandering microchannel making multiple passes each through an evaporator and condenser. With a sufficient number of such passes, intermittent boiling of liquid slugs within each evaporator pass perturbs flow in adjacent channels leaving the device in a perpetually unstable state of oscillation. A PHP is thus distinguished operationally from a loop thermosyphon by having a motive force other than buoyancy and the ability to operate in all gravitational orientations. The most successful PHP models to date track liquid slug motion, sensible heating of the slugs, and mass transfer between liquid slugs and vapor plugs due to evaporation and condensation. However, the predictive capabilities of PHP models remain poor and the numbers assigned to evaporation and condensation heat transfer coefficients are generally not well justified by any realistic physical process. The current study applies methods consistent with state of the art prediction methods in microchannel boiling, to obtain results which predict the PHP’s heat transfer performance and the effect of gravitational orientation on performance.

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Numerical Study on the Effects of using Nanofluids in Pulsating Heat Pipe

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.35.22732 ◽

2018 ◽

Vol 7 (4.35) ◽

pp. 204

Author(s):

M. Zufar ◽

P. Gunnasegaran ◽

Ng K. Ching

Keyword(s):

Thermal Resistance ◽

Heat Pipe ◽

Thermal Performance ◽

Heat Transfer Performance ◽

Numerical Study ◽

Constant Heat Flux ◽

Working Fluid ◽

Pulsating Heat Pipe ◽

Working Fluids ◽

Resistance Value

Pulsating Heat Pipe (PHP) is the next generation heat pipe that has a prospect in improving the heat transfer performance. The type of working fluid use in the PHP has a direct influence on the thermal performance. Incorporating nanofluid in PHP may greatly increase its thermal performance as compared to using base fluid (water). The current work focuses on the simulations of 2-dimensional flows in PHP using working fluids such as diamond, silver (Ag), silica oxide (SiO2) nanofluids and water. Constant heat flux and filling ratio of 50% were used throughout the study. From the results, it was found out that diamond nanofluid has the lowest thermal resistance value as compared to other working fluids. The effect of the number of PHP turns was studied and it was discovered that higher number of turns would produce lower thermal resistance value.

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Numerical study of the thermal performance of a hydrogen pulsating heat pipe

International Journal of Thermal Sciences ◽

10.1016/j.ijthermalsci.2021.107302 ◽

2022 ◽

Vol 172 ◽

pp. 107302

Author(s):

Xiao Sun ◽

Sizhuo Li ◽

Bo Wang ◽

Bo Jiao ◽

John Pfotenhauer ◽

...

Keyword(s):

Heat Pipe ◽

Thermal Performance ◽

Numerical Study ◽

Pulsating Heat Pipe

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Thermal Performance of an Al2O3–Water Nanofluid Pulsating Heat Pipe

Journal of Electronic Packaging ◽

10.1115/1.4024145 ◽

2013 ◽

Vol 135 (3) ◽

Cited By ~ 5

Author(s):

Hamid Reza Seyf ◽

Sejung Kim ◽

Yuwen Zhang

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Volume Fraction ◽

Numerical Study ◽

Pure Water ◽

Working Fluid ◽

Pulsating Heat Pipe ◽

Liquid Slug ◽

Temperature And Pressure ◽

Vapor Temperature

A numerical study is performed to investigate the effects of nanofluids on the heat transfer performance of a pulsating heat pipe (PHP). Pure water is employed as the base fluid while Al2O3 with two different particle sizes, 38.4 and 47 nm, is used as nanoparticle. Different parameters including displacement of liquid slug, vapor temperature and pressure, liquid slug temperature distribution, as well as sensible and latent heat transfer in evaporator and condenser are calculated numerically and compared with the ones for pure water as working fluid. The results show that nanofluid has significant effect on heat transfer enhancement of the system and with increasing volume fraction and decreasing particles diameter the enhancement intensifies.

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