Experimental Study of the Effects of Ferrofluid on Thermal Performance of a Pulsating Heat Pipe

2011 ◽  
Author(s):  
Maziar Mohammadi ◽  
Mohammad Mohammadi ◽  
Amir R. Ghahremani ◽  
M. B. Shafii
Keyword(s):  
Magnetic Field ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Input ◽  
Pure Water ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Water Based ◽  
The Magnetic Field

In this work, a four-turn Pulsating Heat Pipe (PHP) is fabricated and tested experimentally. The novelty of the present PHP is the capability of obtaining various thermal performances at a specific heat input by changing the magnetic field. The effects of working fluid (water and ferrofluid), charging ratio (25%, 40%, and 55%), heat input (25, 35, 45, 55, 65, 75, and 85 W), orientation (vertical and horizontal heat mode), and magnetic field on the thermal performance of PHPs are investigated. The results showed that applying the magnetic field on the water based ferrofluid reduced the thermal resistance of PHP by a factor of 40.5% and 38.3% in comparison with the pure water case for the vertical and horizontal mode, respectively. According to the experimental results, an optimum thermal resistance of 0.38 °C/W was achieved at the following conditions: water-based ferrofluid as the working fluid in the presence of magnetic field, vertical mode, charging ratio of 55%, 7% volumetric concentration, and 85 W heat input. This thermal resistance is 11.5 times better than that of the empty PHP.

Experimental Investigation of a Pulsating Heat Pipe Using Ferrofluid (Magnetic Nanofluid)

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Maziar Mohammadi ◽  
Mohammad Mohammadi ◽  
M. B. Shafii
Keyword(s):  
Magnetic Field ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Input ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Volumetric Concentration ◽  
Magnetic Nanofluid ◽  
Heat Mode ◽  
The Magnetic Field

In this work, a four-turn pulsating heat pipe (PHP) is fabricated and tested experimentally. The novelty of the present PHP is the capability to obtain various thermal performances at a specific heat input by changing the magnetic field. The effects of working fluid (water and ferrofluid), charging ratio (40% and 70%), heat input (35, 45, 55, 65, 75, and 85 W), orientation (horizontal and vertical heat mode), ferrofluid volumetric concentration (2.5% and 7%), and magnetic field on the thermal performance of PHPs are investigated. The results showed that applying the magnetic field on the water-based ferrofluid reduced the thermal resistance of PHP in all orientations. In the presence of a magnetic field, the best thermal performance was achieved at the higher charging ratios (70%) in all orientations.

Experimental Investigation of an Open Loop Pulsating Heat Pipe Using Ferrofluid

2012 ◽  
Author(s):  
Maziar Mohammadi ◽  
Mehdi Taslimifar ◽  
Mohammad Hassan Saidi ◽  
Mohammad Behshad Shafii ◽  
Hossein Afshin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Thermal Performance ◽  
High Heat ◽  
Open Loop ◽  
Working Fluid ◽  
Distilled Water ◽  
Pulsating Heat Pipe ◽  
Resistance Variation

The present work investigates the thermal performance of a five turn Open Loop Pulsating Heat Pipe (OLPHP). The effects of working fluid namely water and ferrofluid, heat input, ferrofluid concentration, charging ratio, and orientation will be considered. Experimental results show that using ferrofluids can enhance the thermal performance in comparison with the case of distilled water. In addition, applying a magnetic field on the OLPHP charged with ferrofluid reduces its thermal resistance. Variation of the ferrofluid concentration results in different thermal performance of the OLPHP. Best charging ratio for the distilled water and ferrofluid without magnetic field is 60% in most of the cases, while in the case of ferrofluid in the presence of magnetic field at low heat inputs, 20% and at high heat inputs 60% of charging ratios have lowest thermal resistance.

Effect of Inclination Angle on the Closed Loop Pulsating Heat Pipe Thermal Performance

2013 ◽  
Author(s):  
Pramod R. Pachghare ◽  
Ashish M. Mahalle
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Inclination Angle ◽  
Heat Input ◽  
Closed Loop ◽  
Pulsating Heat Pipe ◽  
Working Fluids ◽  
Inclination Angles ◽  
R 134A

The closed loop pulsating heat pipe (CLPHP) is a passive two-phase heat transfer device, patented by Akachi (1990). Due to its excellent features, PHP has been considered as one of the promising technologies for electronic cooling, heat exchanger, etc. This paper presents an experimental study shows the effect of inclination angle on the thermal performance of CLPHP, which consist of 10 turns of copper tubes having inner and outer diameter 2 mm and 3.6 mm respectively. The equal lengths of evaporator, condenser and adiabatic sections are 50 mm each. Different working fluids are used as R-134a, Methanol and Water. For all experimentations, an optimum filling ratio was maintained 50% by volume. The thermal performance have been investigated with different inclination angles (viz. 0°, 20°, 40°, 60° and 90°) at various heat input from 5 to 50W in the steps of 5W. The thermal resistance (which is inversely proportional to thermal performance) of CLPHP at various heat input are plotted for different working fluids. The result shows that, the thermal resistance decreases as heat input increases. But at low heat input i.e. upto 25W, the thermal resistance decreases rapidly and the PHP performance is more sensitive to the inclination angle whereas high heat input i.e. above 25W, the thermal resistance decreases smoothly and less independent to the inclination angle. In all inclination angles, vertical bottom heat position (at 90°) of CLPHP gives best thermal performance due to presence of gravity force. At all inclination angles, the working fluid R-134a show best thermal performance followed by methanol and water.

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 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.

scholarly journals Thermal Performance of Micro-Pulsating Heat Pipe

2019 ◽  
Vol 8 (6) ◽  
pp. 2786-2791
Keyword(s):  
Thermal Resistance ◽  
Temperature Profile ◽  
Thermal Performance ◽  
Heat Input ◽  
Computational Study ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Ansys Fluent ◽  
Vof Model ◽  
Flow Circulation

In this study, thermal performance of MPHP is investigated computationally. A case with 0.7mm hydraulic diameter with 7 turns is considered for the study. Simulation is carried out using ANSYS-FLUENT® software by considering water as working fluid with the help of VOF model. Computational study shows the oscillation of fluid inside and formation of new vapor slugs. The heat input is varied from 1.2 W to 4.8 W in the step of 1.2. Flow circulation inside the MPHP is not unidirectional and frequently changes with the pressure disturbance created in the channels. The temperature profile from computational study shows the startup condition is changing with heat input. Thermal resistance of the MPHP decreases with increase in heat input and the corresponding thermal resistance found to be varied from 3.94 to 3.65 K/W.

Thermal Characteristics of a Three-Dimensional Coil Type Pulsating Heat Pipe at Different Heating Modes

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
Satyanand Abraham ◽  
Anand Takawale ◽  
Peter Stephan ◽  
Arvind Pattamatta
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Heat Input ◽  
3D Structure ◽  
Three Dimensional ◽  
Working Fluid ◽  
Coolant Temperature ◽  
Pulsating Heat Pipe ◽  
Condenser Section ◽  
Maximum Heat

Abstract The heat transfer performance of a pulsating heat pipe (PHP) configured as a three-dimensional (3D) structure is reported in the present study. The PHP structure resembles an elongated coil and termed “coil type PHP.” Five different heating modes were created by positioning the evaporator at different locations and placing the PHP device in vertical and horizontal orientations. Studies were conducted primarily with de-ionized water as the working fluid. Limited number of experiments were also performed using binary fluids. The filling ratio was varied from 40% to 80%, while the heat input was varied from 20 W to 240 W. The vertical and horizontal orientations show almost 30 and 10 times reduction in the thermal resistance, respectively, compared with bare PHP tubes without the working fluid. This results in an effective thermal conductivity of more than 3000 W/(m K) and 12,000 W/(m K) for horizontal and vertical orientations, respectively. The use of the binary fluid (10 wt% and 20 wt% of ethanol aqueous solution) results in an increase in the maximum heat input at different heating modes. The temperature of the coolant supplied to the condenser section of the PHP was also varied, and the thermal resistance of the system was observed to reduce with an increase in the coolant temperature.

Promising Technology for Electronic Cooling: Nanofluidic Micro Pulsating Heat Pipes

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Kambiz Jahani ◽  
Maziar Mohammadi ◽  
Mohammad Behshad Shafii ◽  
Zahra Shiee
Keyword(s):  
Magnetic Field ◽  
Thermal Resistance ◽  
Thermal Management ◽  
Thermal Performance ◽  
Microelectromechanical Systems ◽  
Heat Pipes ◽  
Electronic Cooling ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Thermal Management Of Electronics

Currently, the thermal management of microelectromechanical systems (MEMS) has become a challenge. In the present research, a micro pulsating heat pipe (MPHP) with a hydraulic diameter of 508 μm, is experimented. The thermal performance of the MPHP in both the transient and steady conditions, the effects of the working fluid (water, silver nanofluid, and ferrofluid), heating power (4, 8, 12, 16, 20, 24, and 28 W), charging ratio (20, 40, 60, and 80%), inclination angle (0 deg, 25 deg, 45 deg, 75 deg, and 90 deg relative to horizontal axis), and the application of magnetic field, are investigated and thoroughly discussed. The experimental results show that the optimum charging ratio for water is 40%, while this optimum for nanofluids is 60%. In most of situations, the nanofluid charged MPHPs have a lower thermal resistance relative to the water charged ones. For ferrofluid charged MPHP, the application of a magnetic field substantially reduces the thermal resistance. This study proposes an outstanding technique for the thermal management of electronics.

Characteristics of Thermal Performance in High Power LED Package with Heat Pipe

2007 ◽  
Vol 124-126 ◽  
pp. 85-88 ◽  
Author(s):  
Woong Joon Hwang ◽  
Hwa Jun Yeo ◽  
Moo Whan Shin
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Thermal Performance ◽  
High Power ◽  
Pure Water ◽  
Input Power ◽  
Junction Temperature ◽  
Working Fluid ◽  
Sintered Metal ◽  
Forced Cooling

This paper discusses about thermal performance of high power light emitted diode (HPLED) implemented with sintered metal wick type heat pipe(SWHP). The HPLED(2.5 W) samples were surface mounted device(SMD) package used in our experiments. The experiments were made for SWHP with diameters of 6.0 mm. The length of the SWHP is 150 mm. The working fluid in the heat pipes is pure water. The electrical-thermal transient technique was employed for the junction temperature measurement. It was found that the SWHP leads to decreased of thermal resistance by 35 % compared with a simple copper bar in oil bath (forced cooling condition). Employment of copper cap as a LED attachment was more advantageous over the phosphor bronze. After the increase of input power, the thermal resistance of HPLED package has decreased with the increase of effective thermal conductivity of SWHP.

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