EXPERIMENTAL STUDY ON PULSATING HEAT PIPE USING SELF-REWETTING FLUID AS A WORKING FLUID: VISUALIZATION OF THIN LIQUID FILM AND SURFACE WAVE

Self-sustainable motions of the slug flow in oscillating heat pipes have been investigated in the paper. Thin film condensation in the capillary channels of the condenser of the oscillating heat pipes was studied. Instability of the thin liquid film on the characteristics of heat pipes was analysed. The extra thermal resistance caused by the thickness of the thin liquid film was taken into account for the numerical simulation of the oscillatory motions of the slug flow in the heat pipes. Saturated temperatures and pressures of the working fluid in the condenser were obtained. Thermoacoustic theory was applied to calculate heat transport through the adiabatic section of the heat pipes. Experimental studies were carried out to understand the heat transfer behaviours of heat pipes. One heat pipe with the working fluid of HFC-134a was evaluated. The heat pipe is made of aluminium plate and has the width of 50 mm and thickness of 1.9 mm. Numerical and experimental results relevant to the heat transport capability of the heat pipe were analysed and compared.

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Experimental Study on Start-up Characteristics of Pulsating Heat Pipe

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.354-355.87 ◽

2011 ◽

Vol 354-355 ◽

pp. 87-91 ◽

Cited By ~ 5

Author(s):

Xun Wang ◽

Tong Han ◽

Lei Wang ◽

Xin Xin Mao ◽

Cheng Si Yang

Keyword(s):

Experimental Study ◽

Heat Pipe ◽

Filling Ratio ◽

Heating Power ◽

Working Fluid ◽

Incline Angle ◽

Distilled Water ◽

Pulsating Heat Pipe ◽

Start Up ◽

Time Required

Pulsating heat pipe (PHP) with distilled water and acetone as working fluids was experimentally investigated. It is found that the PHP required a certain range of heating power to be started, within which the time required to start the PHP became shorter when the heating power was higher. There was a certain incline angle which is 45°in this experiment to start the PHP more quickly than other angles performed. The minimum power to start the PHP became higher when the filling ratio was higher. Compared with distilled water, the PHP was more readily to be started with acetone as working fluid.

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An Investigation of Evaporation, Boiling, and Heat Transport Performance in Pulstating Heat Pipe

Heat Transfer, Volume 7 ◽

10.1115/imece2002-33334 ◽

2002 ◽

Cited By ~ 6

Author(s):

Qingjun Cai ◽

Reh-Lin Chen ◽

Chung-Lung Chen

Keyword(s):

Temperature Gradient ◽

Liquid Film ◽

Heat Pipe ◽

Heat Transport ◽

Thin Liquid Film ◽

Pulsating Heat Pipe ◽

Liquid Slug ◽

Fill Ratio ◽

Liquid Heat ◽

Observation Results

Pulsating heat pipe (PHP) is a latest development in heat pipe technology. In this paper, evaporation and boiling phenomena are investigated, and liquid heat transport performance in a PHP is measured at different fill ratio as well. The observation results show that phase change in the evaporator may occur by two different mechanisms: 1) evaporation and boiling in thin liquid film on the evaporator wall, 2) generation and collapse of tiny bubbles suspended in the liquid slug. Meanwhile, the temperature measurement indicates that temperature gradient between the evaporator and the condenser is related to liquid latent heat, density, viscosity, and mass filled in.

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Experimental study of a pulsating heat pipe using nanofluid as a working fluid

Fourteenth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm) ◽

10.1109/itherm.2014.6892328 ◽

2014 ◽

Cited By ~ 4

Author(s):

Miguel Gonzalez ◽

Yoon Jo Kim

Keyword(s):

Experimental Study ◽

Heat Pipe ◽

Working Fluid ◽

Pulsating Heat Pipe

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Experimental Study of Evaporator Surface Area Influence on a Closed Loop Pulsating Heat Pipe Performance

Volume 2: Fora ◽

10.1115/fedsm2012-72349 ◽

2012 ◽

Author(s):

Mohammad Hadi Tabatabaee ◽

Mahshid Mohammadi ◽

Mohammad Behshad Shafii

Keyword(s):

Experimental Study ◽

Heat Source ◽

Heat Pipe ◽

Flow Regime ◽

Surface Area ◽

Closed Loop ◽

Heat Removal ◽

Working Fluid ◽

Pulsating Heat Pipe ◽

Widespread Application

Pulsating Heat Pipes are an effective mean for heat removal with the potential for a widespread application in electronic packaging. An experimental study a Closed Loop Pulsating Heat Pipe (CLPHP) constructed of copper tubes formed into four meandering turns is presented. Once configured in a vertical orientation the lower portion of the CLPHP comes in contact with a heat source (called the evaporator) from which it will remove heat through the pulsating action of the two-phase mixture contained within the initially evacuated copper tubes eventually transfer the heat to a heat sink (known as the condenser). Heat fluxes can be measured using temperature data gathered from experiments. Thermocouples connected to the copper tubes at several locations provide this data. Experiments were conducted using deionized water as the working fluid. The surface area of the tubing which comes in contact with the heat source at the evaporator affects the heat removal rates. This effect was studied by varying the surface area in contact with the heat source while providing the same power input. Experiments were conducted using different filling ratios of working fluid (20–70%) for each case. The heat source (heating elements wound around the tubes) was supplied with different power inputs ranging from 10 to 40 W. Results indicate the surface area affects the pulsating action differently for each configuration because of its dependency on the flow regime. These results are presented for each flow regime. The results can be used to optimize the CLPHP according to the flow regime which it will be working in.

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