Thermal Performance of Pulsating Heat Stripes Built With Plastic Materials

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Oguzhan Der ◽  
Marco Marengo ◽  
Volfango Bertola
Keyword(s):  
Heat Pipe ◽  
Low Cost ◽  
Thermal Conductance ◽  
Thermal Response ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Small Unit ◽  
Plastic Materials ◽  
Low Weight ◽  
Polypropylene Sheet

A low-cost, flexible pulsating heat pipe (PHP) was built in a composite polypropylene sheet consisting of three layers joint together by selective laser welding, to address the demand of heat transfer devices characterized by low weight, small unit thickness, low cost, and high mechanical flexibility. A thin, flexible, and lightweight heat pipe is advantageous for various aerospace, aircraft, and portable electronic applications where the device weight, and its mechanical flexibility are essential. The concept is to sandwich a serpentine channel, cut out in a polypropylene sheet and containing a self-propelled mixture of a working fluid with its vapor, between two transparent sheets of the same material; this results into a thin, flat enclosure with parallel channels hence the name “pulsating heat stripes” (PHS). The transient and steady-state thermal response of the device was characterized for different heat input levels and different configurations, either straight or bent at different angles. The equivalent thermal resistance was estimated by measuring the wall temperatures at both the evaporator and the condenser, showing a multifold increase of the equivalent thermal conductance with respect to solid polypropylene.

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.

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.

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.

An Experimental Study of Micro Radially Rotating Heat Pipes With Water as the Working Fluid

2008 ◽  
Author(s):  
Yiding Cao ◽  
Jian Ling
Keyword(s):  
Heat Pipe ◽  
Thermal Conductance ◽  
Heat Pipes ◽  
Working Fluid ◽  
Rotating Speed ◽  
Copper Water ◽  
High Pressure Compressor ◽  
Potential Applications ◽  
Inner Diameter ◽  
Pressure Compressor

In this study, three copper-water rotating heat pipes having inner diameters of 1.5, 2, and 3 mm, respectively, are fabricated and tested. The effectiveness of the copper-water heat pipe is first validated by comparing its performance with that of a copper bar having the same inner and outer diameters. The heat pipes are then tested to prove their reliability, high effective thermal conductance, and critical working limitation. The experimental data shows that the critical limitation may be reached when the inner diameter of the heat pipe is below 1.5 mm under the condition of a low rotating speed. The tests of these water heat pipes could also explore potential applications of radially rotating heat pipes in disks/blades of a high-pressure compressor.

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.

Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector

2012 ◽  
Author(s):  
Shota Sato ◽  
Shigeki Hirasawa ◽  
Tsuyoshi Kawanami ◽  
Katsuaki Shirai
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Solar Collector ◽  
Transfer Rate ◽  
Thermal Conductance ◽  
Filling Ratio ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Single Tube

We experimentally study the thermal conductance of single-tube and loop heat pipes for a solar collector. The evaporator of the heat pipe is 1 m long, 6 mm in diameter and has 30° inclination. The thermal conductance is defined as the heat transfer rate divided by the temperature difference between the evaporator-wall and the condenser-wall. Effects of heat transfer rate, saturation temperature of the working fluid, liquid filling ratio, inclination angle, and position of the evaporator on the thermal conductance are examined. We found that the thermal conductance of the 30°-inclined loop heat pipe with an upper-evaporator is 40–50 (W/K), which is 1.8 times higher than that of the vertical loop type and 3 times higher than that of the single-tube type. Thus, the inclined loop heat pipe is preferable for a solar collector. There is an optimum liquid filling ratio. When the liquid filling ratio is too small, a dry-out portion appears in the evaporator. When the liquid filling ratio is too large, the liquid flows in the condenser to decrease heat transfer area. Also we numerically analyze the thermal conductance of a vertical loop heat pipe.

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

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.

Experimental Investigation of Heat Transfer of Refrigerant Fluid Pulsating Heat Pipe

2017 ◽  
Vol 865 ◽  
pp. 137-142
Author(s):  
Somchai Maneewan ◽  
Chantana Punlek ◽  
Hoy Yen Chan ◽  
Atthakorn Thongtha
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Temperature Difference ◽  
Heat Input ◽  
Filling Ratio ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Filling Volume ◽  
Volume Filling

Heat transfer performances of a pulsating heat pipe (PHP) having internal and external diameter with 4.5 mm and 6 mm with various contents of refrigerant are experimentally investigated. The working fluid as R404A refrigerant was filled in the volume ratios from 0% to 80% and the heat input was controlled in the range from 10 W to 80 W. Obtained results exhibited the ability of R404A refrigerant can enhance the thermal performance in steady state condition. The average temperature difference of the evaporating section and condensing section in the 80% filling volume ratio decreased from 9.5 °C to 2.5 °C when the heating power increase from 10 W to 80 W. The thermal resistance of evaporator and condenser decreased with an increase of the heat input as well. For other filling volume ratios, the trend of temperature difference and thermal resistance was similar to that of the 80% volume filling ratio. Considering the same heat input, the highest heat transfer performance was found at the 80% volume filling ratio. Refrigerant with a relatively low dynamic consistency can lead to relatively high velocity in the PHP that can reduce the temperature difference between the evaporating section and condensing section.

Review of Pulsating Heat Pipe Working Fluid Selection

2012 ◽  
Vol 26 (4) ◽  
pp. 651-656 ◽  
Author(s):  
Brent S. Taft ◽  
Andrew D. Williams ◽  
Bruce L. Drolen
Keyword(s):  
Heat Pipe ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Working Fluid Selection

Experimental Characterization of an Open Loop Pulsating Heat Pipe Cooler

2014 ◽  
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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