scholarly journals Correlations to predict thermal performance affected by working fluid’s properties of vertical and horizontal closed-loop pulsating heat pipe

2016 ◽  
Vol 20 (5) ◽  
pp. 1555-1564
Author(s):  
Phrut Sakulchangsatjatai ◽  
Niti Kammuang-Lue ◽  
Kritsada On-Ai ◽  
Pradit Terdtoon
Keyword(s):  
Heat Pipe ◽  
Thermal Performance ◽  
Closed Loop ◽  
Heat Pipes ◽  
Bond Number ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Pulsating Heat Pipe ◽  
Dimensionless Numbers ◽  
Adiabatic Section

Objectives of this paper are to investigate the effects of dimensionless numbers on the thermal performance, and to establish correlations to predict the thermal performance of the vertical and a horizontal closed-loop pulsating heat pipe. The heat pipes were made of long copper capillary tubes with 26 meandering turns and both the ends were connected together to form a loop. R123, R141b, acetone, ethanol, and water were chosen as variable working fluids with a constant filling ratio of 50% by total volume. The inlet temperature of the heating medium and the adiabatic section temperature were constantly controlled and maintained at 80?C and 50?C, respectively. The thermal performance was represented in terms of the Kutateladze number. It can be concluded that when the Prandtl number of the liquid working fluid, as well as the Karman number, increases, the thermal performance increases. On the other hand, when the Bond number, the Jacob number, and the Aspect ratio increase, the thermal performance decreases. These effects of the dimensionless numbers on the thermal performance are valid for both the heat pipes, except in the case of Bond number which has no effect on the thermal performance as far as the horizontal heat pipe is concerned. Moreover, correlations to predict thermal performance have been successfully established.

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.

Experimental Investigations on Thermal Performance of a Multi-Turn Closed Loop Pulsating Heat Pipe

2012 ◽  
Vol 433-440 ◽  
pp. 5854-5860 ◽  
Author(s):  
Yu Wang ◽  
Wei Yi Li
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Input ◽  
Closed Loop ◽  
Research Work ◽  
Design Parameters ◽  
Working Fluid ◽  
High Heat Flux ◽  
Pulsating Heat Pipe

Closed loop pulsating heat pipe (CLPHP) is a relatively new two-phase passive heat transfer device to suit present requirement of high heat flux dissipation in modern electronic components. The operating mechanism of CLPHP is not well understood and the present state of the technology cannot predict required design parameters for a given task. The aim of research work presented in this paper is to better understand thermal performance of CLPHP. A series of experimental investigation were conducted on a multi-turn CLPHP made of copper capillary tube of 2-mm inner diameter. Two kinds of working fluids viz. ethanol and acetone were employed. The influence characterization has been studied for the variation of heat input and filling ratio (FR) of the tested CLPHP. Thermal performance of the CLPHP is evaluated by heat transfer and thermal resistance. The results strongly demonstrate the effect of heat input and FR of the working fluid on thermal performance of the device.

scholarly journals Thermal performance of Pulsating Heat Pipe on Electric Motor as Cooling Application

2018 ◽  
Vol 67 ◽  
pp. 03035 ◽  
Author(s):  
Nurhalimah Aprianingsih ◽  
Adi Winarta ◽  
Bambang Ariantara ◽  
Nandy Putra
Keyword(s):  
Heat Pipe ◽  
Thermal Management ◽  
Thermal Performance ◽  
Electric Motor ◽  
Management System ◽  
Operating Temperature ◽  
Heat Pipes ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Thermal Management System

Heat generated in an electric motor can increase the operating temperature. The excessive operating temperature will reduce the electric motor performance and shorten the service life. An appropriate thermal management system is required to reduce the electric motor operating temperature. The objective of this study is to determine the thermal performance of pulsating heat pipes which applied to the electric motor thermal management system. A prototype of electric motor thermal management system was made from an induction motor with a cartridge heater instead of a heat-generating rotor and stator. Six pieces of pulsating heat pipe were mounted using hexagonal heat pipe holder which placed inside the electric motor housing. The pulsating heat pipes are made of a copper capillary tube using acetone as working fluid with a filling ratio of 0.5. The electric power input was varied from 30 W to 150 W. The use of pulsating heat pipes can reduce the electric motor surface temperature by 55.3°C with the minimum thermal resistance of 0.151°C/W.

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 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.

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