Visualization of the working fluid in a flat-plate pulsating heat pipe by neutron radiography

2022 ◽  
Vol 185 ◽  
pp. 122336
Author(s):  
Yosuke Yasuda ◽  
Fumika Nabeshima ◽  
Keisuke Horiuchi ◽  
Hiroki Nagai
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Neutron Radiography ◽  
Working Fluid ◽  
Pulsating Heat Pipe

scholarly journals Integration of a Pulsating Heat Pipe in a Flat Plate Heat Sink

2014 ◽  
Author(s):  
Mitchell P. Hoesing ◽  
Gregory J. Michna
Keyword(s):  
Thermal Resistance ◽  
Flat Plate ◽  
Heat Pipe ◽  
Heat Sink ◽  
New Technologies ◽  
Operating Conditions ◽  
Working Fluid ◽  
High Heat Flux ◽  
Pulsating Heat Pipe ◽  
Plate Heat

The ongoing development of faster and smaller electronic components has led to a need for new technologies to effectively dissipate waste thermal energy. The pulsating heat pipe (PHP) shows potential to meet this need, due to its high heat flux capacity, simplicity, and low cost. A 20-turn flat plate PHP was integrated into an aluminum flat plate heat sink with a simulated electronic load. The PHP heat sink used water as the working fluid and had 20 parallel channels with dimensions 2 mm × 2 mm × 119 mm. Experiments were run under various operating conditions, and thermal resistance of the PHP was calculated. The performance enhancement provided by the PHP was assessed by comparing the thermal resistance of the heat sink with no working fluid to that of it charged with water. Uncharged, the PHP was found to have a resistance of 1.97 K/W. Charged to a fill ratio of approximately 75% and oriented vertically, the PHP achieved a resistance of .49 K/W and .53 K/W when the condenser temperature was set to 20°C and 30°C, respectively. When the PHP was tilted to 45° above horizontal the PHP had a resistance of .76 K/W and .59 K/W when the condenser was set 20°C and 30°C, respectively. The PHP greatly improves the heat transfer properties of the heat sink compared to the aluminum plate alone. Additional considerations regarding flat plate PHP design are also presented.

Experimental Investigation of a Flat-Plate Closed-Loop Pulsating Heat Pipe

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Wessel W. Wits ◽  
Gerben Groeneveld ◽  
Henk Jan van Gerner
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Heat Pipe ◽  
Closed Loop ◽  
Electronics Cooling ◽  
Power Input ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Thermo Electric ◽  
Temperature And Pressure

The thermal performance and operating modi of a flat-plate closed-loop pulsating heat pipe (PHP) are experimentally observed. The PHP is manufactured through computer numerical controlled milling and vacuum brazing of stainless steel 316 L. Next to a plain closed-loop PHP, also one that promotes fluid circulation through passive Tesla-type valves was developed. Each channel has a 2 × 2 mm2 square cross section, and in total, 12 parallel channels fit within the 50 × 200 mm2 effective area. During the experimental investigation, the power input was increased from 20 W to 100 W, while cooling was performed using a thermo-electric cooler (TEC) and thermostat bath. Three working fluids were assessed: water, methanol, and ammonia. The PHP was charged with a 40% filling ratio. Thermal resistances were obtained for different inclination angles. It was observed that the PHP operates well in vertical evaporator-down orientation but not horizontally. Moreover, experiments show that the minimum operating orientation is between 15 and 30 deg. Two operating modi are observed, namely, the thermosyphon modus, without excessive fluctuations, and the pulsating modus, in which both the temperature and pressure responses oscillate frequently and violently. Overall thermal resistances were determined as low as 0.15 K/W (ammonia) up to 0.28 and 0.48 K/W (water and methanol, respectively) at a power input of 100 W in the vertical evaporator-down orientation. Infrared thermography was used to visualize the working fluid behavior within the PHPs. Infrared observations correlated well with temperature and pressure measurements. The experimental results demonstrated that the developed flat-plate PHP design, suitable for high-volume production, is a promising candidate for electronics cooling applications.

A Simple Model Used to Predict the Thermal Performance of Flat-Plate Closed-Loop Pulsating Heat Pipe

2013 ◽  
Vol 316-317 ◽  
pp. 7-12
Author(s):  
Qing Ping Wu ◽  
Rui Xiang Wang ◽  
Xiao Peng Liu ◽  
Ya Jun Li ◽  
Rong Ji Xu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Flat Plate ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Tilt Angle ◽  
Heat Load ◽  
Closed Loop ◽  
Working Fluid ◽  
Pulsating Heat Pipe

The thermal performance Rov of Flat-Plate Closed-Loop Pulsating Heat Pipe(FCLPHP) are effected by several elements such as the heat load Q, the tilt angle θ and the filling ratio F, they are interacted each other. In order to predict the effect of Q and θ on the thermal performance at locations Q and θ other than the experimental data conditions, and to study the relationship among the Rov, Q and θ in the range of the experimental data, we need a fitted regression model to estimate the function relationship that describes the data. The postulated depends on the range of the regression variables encountered in the data. In this paper, a simple model was developed. Since the coefficients in the model have been estimated from the experimental data, studies were carried out on an experimental set-up. FC72 was employed as working fluid. Method of least squares was used for building the model. By using the model, effects of the heat load and the tilt angle on the thermal performance of FCLPHP were discussed. It was found that the tilt angle had minimum value in a certain heat load in the experimental range (θ=30° -70°), and it increases with the increase of heat load. A sensitivity analysis was done with the model.

scholarly journals Experimental study of a closed loop flat plate pulsating heat pipe under a varying gravity force

2015 ◽  
Vol 96 ◽  
pp. 23-34 ◽  
Author(s):  
V. Ayel ◽  
L. Araneo ◽  
A. Scalambra ◽  
M. Mameli ◽  
C. Romestant ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Heat Pipe ◽  
Closed Loop ◽  
Gravity Force ◽  
Pulsating Heat Pipe

scholarly journals Thermal Characteristic and Analysis of Microchannel Structure Flat Plate Pulsating Heat Pipe With Silver Nanofluid

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 51724-51734 ◽  
Author(s):  
Hui Xu ◽  
Ping Zhang ◽  
Lipei Yan ◽  
Dehao Xu ◽  
Wei Ma ◽  
...  
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Thermal Characteristic ◽  
Pulsating Heat Pipe

scholarly journals Problems of sodium using in pulsating heat pipe made from fused silica

2018 ◽  
Vol 207 ◽  
pp. 04004
Author(s):  
Radovan Nosek ◽  
Tatiana Liptáková ◽  
Libor Trško ◽  
Zuzana Kolková ◽  
Milan Malcho ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Pipe ◽  
Alkali Metals ◽  
High Efficiency ◽  
Fused Silica ◽  
Operating Conditions ◽  
Liquid Sodium ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
High Temperature Reaction

You Heat pipe is a high efficiency heat transfer element, depends on the evaporation, condensation and circulation of inside working fluid. The working fluid of a high temperature pulsating heat pipe is generally alkali metals, and sodium heat pipe can operate in range of 500-1100°C. In order to investigate terminal velocity of working fluid, the glass pulsating heat pipe was produced for experimental purposes. The experiment was carried out, in order to simulate real operating conditions in range of 500-1100°C. Sudden boiling of liquid sodium (b.p. = 883°C at 1 atm) inside the all quartz-made heat pipe results in high-temperature reaction of sodium vapour with the inner wall surface. The reaction became more aggressive with increasing vapour temperature and resulted in heat pipe explosion. The evaluation of damage character is analysed in this paper.

THERMAL-HYDRAULIC CHARACTERIZATION OF A FLAT PLATE PULSATING HEAT PIPE FOR AUTOMOTIVE APPLICATIONS

2015 ◽  
Vol 3 (4) ◽  
pp. 413-425 ◽  
Author(s):  
V. Manno ◽  
Sauro Filippeschi ◽  
Mauro Mameli ◽  
Cyril Romestant ◽  
Vincent Ayel ◽  
...  
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Automotive Applications ◽  
Pulsating Heat Pipe

Operating Activity Visualization and Thermal Performance Measurement of Pulsating Heat Pipe

2016 ◽  
Vol 369 ◽  
pp. 42-47 ◽  
Author(s):  
Patrik Nemec ◽  
Zuzana Kolková ◽  
Milan Malcho
Keyword(s):  
Heat Transfer ◽  
Performance Measurement ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Vapour Phase ◽  
Working Fluid ◽  
Internal Diameter ◽  
Pulsating Heat Pipe ◽  
Inner Diameter ◽  
Thermo Physical Properties

Heat pipe is well known device which is used to heat transfer phase-change of working fluid. Pulsating heat pipe (PHP) is special type of heat pipe which heat transfer by pulsating movement of working fluid. Article deals about operating activity and thermal performance measurement of this special heat pipe. Operating activity visualization of PHP was performed with PHP made from glass. The two types of PHPs were made. The first PHP has internal diameter of tube 1 mm, second PHP has internal diameter of tube 1.5 mm and both PHPs have eleven meanders. The working fluids used in PHP were water and Fluorinert FC-72. These fluids were chose for their different thermo-physical properties and the visualization observe formation of liquid and vapour phase working fluid during filling process and working operation.Next, the article describes thermal performance measurement of PHP depending on working fluid amount and heat source temperature. Measurement was performed with PHP made from copper tube with inner diameter 1.5 mm curved to the twenty one meanders and filled with water. The results give us image about formation and distribution of working fluid in pulsating heat pipe and about influence of working fluid amount on the heat transfer ability of pulsating heat pipe.

Effects of Surface Coating of Nanoparticles on Thermal Performance of Open Loop Pulsating Heat Pipes

2012 ◽  
Author(s):  
Mehdi Taslimifar ◽  
Maziar Mohammadi ◽  
Ali Adibnia ◽  
Hossein Afshin ◽  
Mohammad Hassan Saidi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Surface Coating ◽  
Heat Pipes ◽  
Open Loop ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Performance Of Heat Transfer

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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