Parametric Behaviour of Closed Loop Pulsating Heat Pipe in the Presence of Water As a Working Fluid

2019 ◽  
Author(s):  
Nagendra P. Yadav ◽  
Madhuri ◽  
Anil Kumar
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Integrated Circuit ◽  
Closed Loop ◽  
Electronic Devices ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Power Inputs ◽  
Variable Power ◽  
Circuit Technology

Abstract This paper focuses on the parametric behavior of a closed loop pulsating heat pipe in the presence of water as a working fluid. The experimental study was done in the presence of different vacuum pressures inside the heat pipe with 50 percent filling ratio. The temperature was measured through the DAQ system with help of Lab VIEW 15.1 software at 12 locations of heat pipe at variable power inputs (10W–70W). Thermal resistance and variation of temperature are used to predict the performance of the heat pipe. Thermal resistance of heat pipe decreases with decrease in vacuum pressure inside the heat pipe. This work is useful for the transfer of heat of electronic devices and integrated circuit technology due to the high coefficient of convective heat transfer in the presence of phase change of working fluid inside the heat pipe.

Thermal Resistance of a Rotating Closed-Loop Pulsating Heat Pipe: Effect of Centrifugal Accelerations

2016 ◽  
Vol 851 ◽  
pp. 292-298
Author(s):  
Niti Kammuang-Lue ◽  
Deuansavanh Phommavongsa ◽  
Kritsada On-Ai ◽  
Phrut Sakulchangsatjatai ◽  
Pradit Terdtoon
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Closed Loop ◽  
Working Fluid ◽  
Outer Side ◽  
Gravitational Acceleration ◽  
Pulsating Heat Pipe ◽  
Centrifugal Acceleration ◽  
Condenser Section ◽  
Evaporator Section

Objective of this study is to experimentally investigate the effect of centrifugal accelerations on thermal resistance of the rotating closed-loop pulsating heat pipe (RCLPHP). The RCLPHPs were made of a copper tube with internal diameter of 1.50 and 1.78 mm and bent into flower’s petal-shape and arranged into a circle with 11 turns. The evaporator section located at the outer end of the bundle while the condenser section placed around the center of the RCLPHP with no adiabatic section. Both sections had an identical length of 50 mm. R123, and ethanol was filled as working fluid respectively. The RCLPHP was installed on the test rig and it was rotated by the DC motor at the centrifugal acceleration of 0.5, 1, 3, 5, 10, and 20 times of the gravitational acceleration considering at the connection between the evaporator and condenser section. Heat input was generated by electrical annular-plate heaters and varied from 30 to 50, 100, 150, and 200 W. Ceramic papers, wooden plate, and insulation sheet were consecutively attached on the outer side of the heaters in order to prevent the heat loss from the heater. It can be concluded that when the centrifugal acceleration increases, the thermal resistance continuously decreases since the condensate flows back to the evaporator section more rapidly.

Experimental Investigation and Performance Evaluation of a Multi Turn Closed Loop Pulsating Heat Pipe

2014 ◽  
Vol 592-594 ◽  
pp. 1554-1558 ◽  
Author(s):  
N. Narendra Babu ◽  
Rudra Naik
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Heat Pipe ◽  
Closed Loop ◽  
Experimental Result ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Working Fluids

Pulsating heat pipe (PHP) is a passive heat transfer device, which transfers heat from one region to another with exceptional heat transfer capacity. It utilizes the latent heat of vaporization of the working fluid as well as the sensible heat. As a result, the effective thermal conductivity is higher than that of the conductors. An experimental study on three turn closed loop pulsating heat pipe with three different working fluids viz., Acetone, Methanol, Heptane and distilled water were employed. The PHP is made up of brass material with an inner diameter of 1.95mm, with a total length of 1150 mm for different fill ratios (FR) was employed .The PHP is tested for the thermal resistance and the heat transfer coefficient. The experimental result strongly demonstrates that acetone is a better working fluid among the working fluids considered in terms of higher heat transfer coefficient and lower thermal resistance.

scholarly journals Effect of Working Fluid on Thermal Performance of Closed Loop Pulsating Heat Pipe

2019 ◽  
Vol 9 (2) ◽  
pp. 953-956
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Closed Loop ◽  
Filling Ratio ◽  
Working Fluid ◽  
External Diameter ◽  
Pulsating Heat Pipe ◽  
Condenser Section ◽  
Heat Transfer Efficiency ◽  
Bottom Heat

The pulsing heat pipe (PHP) is an technology that is increasingly capable of applying many manufacturing areas, but a thorough knowledge of its thermo-hydrodynamic There's far from enough system. This research explored the features of oscillation and the heat transfer efficiency of a closed-loop PHP using an internal and external diameter copper tube with 2.0 and 3.0 mm respectively. For all experimentation, filling ratio (FR) was 40%, five turns and different heat inputs of 20 to 80 W was supplied to PHP. The position of the PHP was vertical bottom heat type. 52 mm, 170 mm,60 mm was retained for the duration of the evaporator, adiabatic and condenser section. Water, Ethanol are chosen as working liquids. To understand, thermal resistance features and median evaporator pressures for multiple operating liquids at distinct heat inputs. An significant consideration for the results of PHPs is the research on PHP stated operating fluid. The result demonstrates that, with the rise of the heating output from 20 to 80 W, where as steadily increases above 80W, the thermal resistance reduces faster. By comparing Water , Ethanol working fluids, Ethanol provides the highest heat performance . The simulation is performed in Mat lab and the results have been contrasted

Experimental Investigation of Closed Loop Pulsating Heat Pipe With Nanofluids

2009 ◽  
Author(s):  
Hamed Jamshidi ◽  
Sajad Arabnejad ◽  
Mohammad Behshad Shafii ◽  
Yadollah Saboohi ◽  
Ramin Rasoulian
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Closed Loop ◽  
Filling Ratio ◽  
Nano Particles ◽  
Working Fluid ◽  
Sudden Increase ◽  
Pulsating Heat Pipe ◽  
Optimum Performance ◽  
The Impact

In this paper, the effect of several different parameters on the thermal resistance of a Closed Loop Pulsating Heat Pipe (CLPHP) has been investigated. These parameters include the working fluid, the inclination angle, the filling ratio and the heat influx. Also, the impact of using nanofluids with different nano-particle concentrations has been analyzed. It was observed that a CLPHP can increase the heat transfer up to 11.5 times compared to an empty pipe. Optimum performance for a system with the water-silver nanofluid was achieved at conditions of 50% filling ratio and 0.9 K/W of thermal resistance, and for the water-titanium oxide system, these optimal conditions were found to be 40% filling ratio and 0.8 K/W of thermal resistance. In addition, the optimum performance for pure water occurs at a filling ratio of 40% and a thermal resistance of 1.15 K/W. The nanofluid reduces the thermal resistance by 30%. With a decrease in the concentration of nano-particles in the base fluid, the performance of the system decreases as well and the total thermal resistance increases. In low powers (under 20 W), the two-phase flow pattern inside the pipes was slug-plug, but in higher powers (over 30 W), this changed to an annular flow. The performance of the system was better in the annular mode, but there was a probability of dry out and sudden increase of condenser temperature.

scholarly journals Characterization of a Closed Loop Pulsating Heat Pipe Using Ethanol with Different Angles

2021 ◽  
Vol 39 (4) ◽  
pp. 1365-1371
Author(s):  
Israa S. Ahmed ◽  
Hussain S. Abd ◽  
Ayad M. Al Jubori
Keyword(s):  
Heat Pipe ◽  
Thermal Performance ◽  
Closed Loop ◽  
Power Input ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Power Inputs ◽  
Inclination Angles ◽  
Dry Out

In low-temperature difference, a closed-loop pulsating heat pipe (CLPHP) can be used as a cooling device due to its capability to transfer heat. The thermal performance of the CLPHP is affected by the working fluids. In this work, the effects of some operating parameters such as using ethanol as working fluid with 0.5 filling ratio, orientation, and power inputs are offered based on experimental study. Where the CLPHP was constructed and tested to achieve a better vision into the effect of orientation of 0°, 15°, 30°, 45°, and 90°, and power input of 50 W, 115 W, 215 W, and 450 W on the heat transfer characteristics and the thermal performance. The results indicated that the minimum thermal resistance can be reached at 0.1585 (℃/W) with an orientation of 90° and a power input of 450 W. The results revealed that the inclination angles and power inputs had considerable influence on the enhancement of the thermal performance of the CLPHP. For the low boiling temperature of the working fluid, the power input is more favorable because of fast startup compared with a high power input that leads to some difficulties like the dry-out phenomenon.

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 Experiment Study on Improved Closed Loop Pulsating Heat Pipe with Silver/Water Nanofluid

2013 ◽  
Vol 732-733 ◽  
pp. 462-466
Author(s):  
Wei Xiu Shi ◽  
Wei Yi Li ◽  
Li Sheng Pan
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Closed Loop ◽  
Filling Ratio ◽  
Pulsating Heat Pipe ◽  
Start Up ◽  
High Heating ◽  
Operation Stability ◽  
Heat Transfer Limit

Start up and heat transfer performances of improved closed loop pulsating heat pipe (ICLPHP) charged with water and silver/water nanofluid, respectively, were investigated experimentally with angles of 90° and 60°. Both the average evaporator wall temperature and the overall thermal resistance of the ICLPHP with different working fluids and at the volume filling ratio of 35% were tested and compared. Experimental results showed that nanofluid caused different thermal performances of ICLPHP. Within the experiment range, silver/water nanofluid can improve operation stability and heat transfer limit and reduce starting power compared with water. With high heating power, thermal resistance of nanofluid was lower than that of water. With inclination of 60°, ICLPHP with nanofluid operated better and reduced sensitivity of inclination.

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.

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.

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