Characterisation of a Novel Pulsating Heat Pipe Cooler for Power Electronics at Extreme Ambient Temperatures

2015 ◽  
Author(s):  
Daniele Torresin ◽  
Mathieu Habert ◽  
Violette Mounier ◽  
Francesco Agostini ◽  
Bruno Agostini
Keyword(s):  
Heat Pipe ◽  
Low Cost ◽  
Saturation Temperature ◽  
Open Loop ◽  
Experimental Results ◽  
Fluid Distribution ◽  
Pulsating Heat Pipe ◽  
Ambient Temperatures ◽  
Air Temperatures ◽  
Thermo Physical Properties

A compact and low cost pulsating heat pipe cooler (PHP) based on automotive technology is presented. This technology uses numerous aluminium MultiPort Extruded (MPE) tubes with capillary sized channels disposed in parallel to achieve the desired compactness. The sub-channels of the MPEs are connected in a serpentine manner by means of fluid distribution elements integrated in the evaporator and condenser manifolds. This configuration enables the oscillation of liquid slugs and elongated bubbles between the evaporator and the condenser areas. In the present paper the experimental results of an open loop type PHP with refrigerants fluids R134a and R245fa are presented. Tests have been carried out for air temperatures ranging between −60 and 60 °C at a fixed air flow rate of 480 m3/h and heat loads from 3 to 13 W/cm2. The experimental results show the different thermo-physical properties effect of the two tested fluids on the cooler performances: R134a is more adapted to low saturation temperature than R245fa and the contrary has been observed at high saturation temperatures. This is due to the fact that R245fa reaches its viscous limit at low temperatures while at high temperatures R134a reaches its critical temperature.

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.

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

2015 ◽  
Vol 105 ◽  
pp. 105-112 ◽  
Author(s):  
M. Lutfor Rahman ◽  
Fariha Mir ◽  
Sumaiya Nawrin ◽  
R.A. Sultan ◽  
Mohammad Ali
Keyword(s):  
Heat Pipe ◽  
Open Loop ◽  
Performance Characteristics ◽  
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.

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 Study on Flow Visualizing and Heat Transfer Characteristic of Pulsating Heat Pipe

2007 ◽  
Author(s):  
Li Jia ◽  
Dayan Yin
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Flow Patterns ◽  
Bulk Flow ◽  
Experimental Results ◽  
Pulsating Heat Pipe ◽  
Transition Flow ◽  
Fill Ratio

The flow of looped pulsating heat pipe was studied by a visualizing experiment, and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The experimental results indicate that bulk flow, transition flow and annular flow are the major flow patterns in PHP. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred form bulk flow to semi-annual flow and annual flow, and the performance of heat transfer is improved. In the experiment, nuclear boiling, the convergence and break up of liquid-plug and vapor-slug were observed. The influence characterization has been done for the variation of fill ration, heat transfer rate, non-condensable gas and inclination angle. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%; the heat resistance is decreased with heat transfer rate, and non-condensable gas also has significant influence on it. The temperature of tubes in heating, condensing and observe sections were recorded, The fluctuation of heat pipe wall temperature was analysed, and the phenomena of suddently increase or decrease of temperature, the unregular fluctuation of temperature were analyzed. Otherwise the response time under different conditions was also analyzed.

Experimental Research on Heat Transfer Characteristics of Pulsating Heat Pipe

2008 ◽  
Author(s):  
Li Jia ◽  
Yan Li
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Experimental Research ◽  
Transfer Rate ◽  
Experimental Results ◽  
Pulsating Heat Pipe ◽  
Heat Transfer Characteristics ◽  
Fill Ratio ◽  
Transfer Characteristics

Experimental research was conducted to understand heat transfer characteristics of pulsating heat pipe in this paper. The PHP is made of high quality glass capillary tube. The heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage under different fill ratio. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appeares in top heating condition. The flow pattern in PHP is transferred form bulk flow to semi-annual flow and annual flow, and the performance of heat transfer is improved for down heating case under different fill ratios and heat transfer rate. The experimental results show that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

Thermal performance of an open loop closed end pulsating heat pipe

2011 ◽  
Vol 48 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Manabendra Saha ◽  
C. M. Feroz ◽  
F. Ahmed ◽  
T. Mujib
Keyword(s):  
Heat Pipe ◽  
Thermal Performance ◽  
Open Loop ◽  
Pulsating Heat Pipe

scholarly journals A SINGLE LOOP PULSATING HEAT PIPE IN VARYING GRAVITY CONDITIONS: EXPERIMENTAL RESULTS AND NUMERICAL SIMULATIONS

2018 ◽  
Author(s):  
Luca Pietrasanta ◽  
Daniele Mangini ◽  
Davide Fioriti ◽  
Nicolas Miche ◽  
Manolia Andredaki ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Heat Pipe ◽  
Experimental Results ◽  
Pulsating Heat Pipe ◽  
Single Loop

Dynamics of endotoxin fever in the rabbit

1986 ◽  
Vol 60 (5) ◽  
pp. 1504-1510 ◽  
Author(s):  
R. Graener ◽  
J. Werner
Keyword(s):  
Core Temperature ◽  
Dynamic Properties ◽  
Experimental Results ◽  
Evaporative Heat Loss ◽  
Climatic Chamber ◽  
Ambient Temperatures ◽  
Air Temperatures ◽  
Time Courses ◽  
Dynamic Shift ◽  
Effector Mechanisms

To analyze the dynamic properties of body temperature and effector mechanisms during endotoxin fever, both experimental and mathematical procedures were applied. Experiments were carried out on rabbits in a climatic chamber at various ambient temperatures. Salmonella typhosa endotoxin (0.1 microgram/kg) was injected into an ear vein. A biphasic core temperature increase evoked by different effector mechanisms depending on ambient temperature was observed. A mathematical model based on experimental results with nonfebrile rabbits predicts the effector behavior at all ambient temperatures. From a comparison of experimental results with the model prediction, it is concluded that the increase of core temperature during fever is essentially caused by a dynamic shift of the controller characteristics. The effect of the pyrogen may be simulated by a resultant fever-controlling signal that is biphasic but increases more steeply than does core temperature. The analysis suggests that the three possible fever-driving effectors, metabolism, ear blood flow, and respiratory evaporative heat loss, should be controlled by the same resultant signal, although the time courses of the effectors and of core temperature vary distinctly at different air temperatures. The model uses an additive controller structure.

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