Experimental Investigation of Parameters Affecting Performance of Pulsating Heat Pipe

2017 ◽  
Author(s):  
Pawan Singh Kathait ◽  
Rajnish N. Sharma
Keyword(s):  
Heat Pipe ◽  
High Efficiency ◽  
Electronics Cooling ◽  
Heat Fluxes ◽  
Pulsating Heat Pipe ◽  
Two Phase ◽  
Suitable Candidate ◽  
Thermally Induced ◽  
Large Heat ◽  
Efficient Heat Transfer

Pulsating heat pipe (PHP) is a two phase highly efficient heat transfer device, due to its simple and flexible construction; it can be manufactured for a variety of applications. PHP works on thermally induced self-sustaining oscillation of liquid plugs and vapor slugs, so it does not have any moving parts either. Ease of manufacturing, potential for high efficiency at different scales and the ability to handle large heat fluxes has the PHP a suitable candidate for microscale electronics cooling or power electronics cooling. However, this technology is still in developing phase and there is at present no comprehensive model which can be used to design a PHP for a specific application. There are many parameters which affect PHP operation and a thorough understanding of the relation between all the variables is first required. The present study is an attempt to investigate experimentally the effects of various parameters on PHP startup, based on startup temperature measurements under varying heat input and carefully controlled conditions. It has been observed that the oscillations in PHP start (startup) as soon as it reaches a minimum temperature corresponding to the minimum Etvos number required for vapor bubble rise.

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 A Dynamic Film Model of the Pulsating Heat Pipe

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Vadim S. Nikolayev
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Capillary Tube ◽  
Numerical Code ◽  
Oscillating Flow ◽  
Pulsating Heat Pipe ◽  
Two Phase ◽  
Thermally Induced ◽  
Film Evaporation ◽  
Condensation Model

This article deals with the numerical modeling of the pulsating heat pipe (PHP) and is based on the film evaporation/condensation model recently applied to the single-bubble PHP (Das et al., 2010, “Thermally Induced Two-Phase Oscillating Flow Inside a Capillary Tube,” Int. J. Heat Mass Transfer, 53(19–20), pp. 3905–3913). The described numerical code can treat the PHP of an arbitrary number of bubbles and branches. Several phenomena that occur inside the PHP are taken into account: coalescence of liquid plugs, film junction or rupture, etc. The model reproduces some of the experimentally observed regimes of functioning of the PHP such as chaotic or intermittent oscillations of large amplitudes. Some results on the PHP heat transfer are discussed.

Effect of Inclination Angle on Pulsating Heat Pipe Performance

2014 ◽  
Author(s):  
Sagar Babu Paudel ◽  
Gregory J. Michna
Keyword(s):  
Thermal Resistance ◽  
Low Cost ◽  
Electronics Cooling ◽  
High Heat ◽  
Heat Fluxes ◽  
Pulsating Heat Pipe ◽  
Two Phase ◽  
Vertical Orientation ◽  
Horizontal Orientation ◽  
Copper Tubing

Micro-electronic devices are creating ever-increasing demands on their thermal management systems due to their decreasing size and increasing power. Pulsating heat pipes (PHPs) are one possible solution for electronics cooling applications. A PHP is a passive, two-phase heat transfer system which has been shown to have the advantages of the ability to accommodate very high heat fluxes and of relatively low cost, due to its wickless construction. In this investigation, a 20-turn PHP was constructed out of 1.6-mm inner diameter copper tubing. The PHP was operated in vertical and horizontal positions with a filling ratio of 77%. PHP pressure variations, indicating PHP operation, were first observed when the power was increased to 16 W for the vertical orientation (90°). For angles orientations, in general more power was required to induce pulsation. For the 60°, 45°, and 30° orientations, the required startup power was similar to that for the vertical case. In the PHP in the horizontal orientation (0°), pulsation did not begin until a heater input of 30 W was applied, and the thermal resistance only decreased slightly upon startup. Under steady-state operation at the highest heat fluxes, the thermal resistance was lowest for the vertical orientation.

Numerical Study on Flow and Heat and Mass Transfer in Pulsating Heat Pipe

2019 ◽  
Author(s):  
Jian-Hong Liu ◽  
Fu-Min Shang ◽  
Nikolay Efimov
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Heat Pipe ◽  
Gas Phase ◽  
Heat And Mass Transfer ◽  
Mixture Model ◽  
Volume Fraction ◽  
Pulsating Heat Pipe ◽  
Two Phase ◽  
Pipe Model

Abstract Numerical simulation was performed to establishing a two-dimensional pulsating heat pipe model, to investigate the flow and heat transfer characteristics in the pulsating heat pipe by using the Mixture and Euler models, which were unsteady models of vapor-liquid two-phase, based on the control-volume numerical procedure utilizing the semi-implicit method. Through comparing and analyzing the volume fraction and velocity magnitude of gas phase to decide which model was more suitable for numerical simulation of the pulsating heat pipe in heat and mass transfer research. It was showed there had gas phase forming in stable circulation flow in the heating section, the adiabatic section using the Mixture and Euler models respectively, and they were all in a fluctuating state at 10s, besides, the pulsating heat pipe had been starting up at 1s and stabilizing at 5s, it was all found that small bubbles in the heat pipe coalescing into large bubbles and gradually forming into liquid plugs and gas columns from the contours of volume fraction of the gas phase; through comparing the contours of gas phase velocity, it could be seen that there had further stably oscillating flow and relatively stabler gas-liquid two-phase running speed in the pulsating heat pipe used the Mixture model, the result was consistent with the conclusion of the paper[11] extremely, from this it could conclude that the Mixture model could be better simulate the vaporization-condensation process in the pulsating heat pipe, which could provide an effective theoretical support for further understanding and studying the phase change heat and mass transfer mechanism of the pulsating heat pipe.

scholarly journals Problems of sodium using in pulsating heat pipe made from fused silica

2018 ◽  
Vol 207 ◽  
pp. 04004
Author(s):  
Radovan Nosek ◽  
Tatiana Liptáková ◽  
Libor Trško ◽  
Zuzana Kolková ◽  
Milan Malcho ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Pipe ◽  
Alkali Metals ◽  
High Efficiency ◽  
Fused Silica ◽  
Operating Conditions ◽  
Liquid Sodium ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
High Temperature Reaction

You Heat pipe is a high efficiency heat transfer element, depends on the evaporation, condensation and circulation of inside working fluid. The working fluid of a high temperature pulsating heat pipe is generally alkali metals, and sodium heat pipe can operate in range of 500-1100°C. In order to investigate terminal velocity of working fluid, the glass pulsating heat pipe was produced for experimental purposes. The experiment was carried out, in order to simulate real operating conditions in range of 500-1100°C. Sudden boiling of liquid sodium (b.p. = 883°C at 1 atm) inside the all quartz-made heat pipe results in high-temperature reaction of sodium vapour with the inner wall surface. The reaction became more aggressive with increasing vapour temperature and resulted in heat pipe explosion. The evaluation of damage character is analysed in this paper.

scholarly journals Advanced numerical method for a thermally induced slug flow: application to a capillary closed loop pulsating heat pipe

2016 ◽  
Vol 82 (7) ◽  
pp. 375-397 ◽  
Author(s):  
M. Manzoni ◽  
M. Mameli ◽  
C. de Falco ◽  
L. Araneo ◽  
S. Filippeschi ◽  
...  
Keyword(s):  
Numerical Method ◽  
Heat Pipe ◽  
Slug Flow ◽  
Closed Loop ◽  
Pulsating Heat Pipe ◽  
Thermally Induced

Experimental Investigation of Enhanced Two-Phase Evaporator Using Aluminum Foams

2015 ◽  
Author(s):  
Francesco Agostini ◽  
Waylon Puckett ◽  
Ryan Nelson ◽  
Daniele Torresin ◽  
Bruno Agostini ◽  
...  
Keyword(s):  
Aluminum Foam ◽  
Metal Foam ◽  
Electronics Cooling ◽  
Base Plate ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Working Fluid ◽  
Vapor Flow ◽  
Base Temperature ◽  
Two Phase

A novel two-phase thermosyphon with a metal foam based evaporator is presented as a solution for the cooling of power-electronic semiconductor modules. A horizontal evaporator configuration is investigated: the evaporator consists of an aluminum chamber, with aluminum foam brazed to the base plate in three different configurations. One of the configurations has an open vapor chamber above the foam, another has foam filling the entire evaporator chamber, and the third has bores drilled in the foam parallel to the base plate from inlet to outlet along the direction of the vapor flow. The aluminum foam has a porosity of 95%, and a pore density of 20 PPI (pores per inch). A liquid distribution and a vapor collector chamber are respectively present at the entrance and at the exit of the evaporator. The power modules are attached on the evaporator body that collects the heat generated during the operation of the semiconductor devices. A vapor riser guides the vapor to a finned-tube air-cooled heat exchanger. A liquid downcomer from the condenser constantly feeds the evaporator channels. The system works with gravity-driven circulation only. The described system was designed and tested with an extensive experimental campaign. The evaporators were tested for power losses ranging between 500 and 3000 W, corresponding to applied heat fluxes between 3 and 20 W/cm2. The experimental results will be presented for inlet air at ambient temperature of 20°C with volumetric flow rates between 100 and 680 m3/h. The working fluid was refrigerant R245fa. The fluid filling effect was investigated. For each evaporator the results will be presented in terms of maximum thermal resistance and cooler base temperature. The base temperature distribution between different evaporators will also be presented and discussed being an important design parameter in power electronics cooling. Thermal resistances were measured between 15 and 30 K/kW. The experimental results indicated a promising conclusion favoring the implementation of aluminum foam evaporators for enhancement of heat transfer during pool boiling.

Experimental Investigation of Fluid Motion in Pulsating Heat Pipe

2015 ◽  
Author(s):  
Hyung Yun Noh ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Latent Heat ◽  
High Speed ◽  
Fluid Motion ◽  
Pulsating Heat Pipe ◽  
Operating Characteristics ◽  
Two Phase ◽  
Saturation State ◽  
Circulation Mode

In this research, operating characteristics and heat transfer phenomena in 2-turn pulsating heat pipe operating in a circulation mode were experimentally investigated. Temperature, pressure and high-speed flow visualization data were obtained with the variation of diameters (1.2 mm, 1.7 mm and 2.2 mm) and input powers. The overall pressure variation from start-up to steady state was measured using the pressure transmitters in the evaporator section. Heat transfer phenomena were investigated using homogeneous-equilibrium model. Thermodynamic state of two-phase mixture at the exit of evaporator is identified as a saturation state using obtained temperature and pressure data. The ratio of sensible heat to latent heat changed with the variation of diameters and input powers. It was found that each evaporator has a different ratio and latent heat was dominant in most experimental cases.

Experimental Study of Heat Pipe Exchanger for High Power LED Cooling System

2011 ◽  
Vol 295-297 ◽  
pp. 1985-1988
Author(s):  
Yu Jun Gou ◽  
Zhong Liang Liu ◽  
Xiao Hui Zhong
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
High Power ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Cooling System ◽  
Two Phase ◽  
High Power Led ◽  
New Type ◽  
Two Phase Heat Transfer

A new cooling concept for high power LED by combining the heat release of high power LED with two-phase heat transfer heat pipes was proposed, and in this study a new type of heat pipe with specific fins structure was developed. Through experimental results, we found the new heat pipe heat exchanger has the features of high efficiency of heat dissipation and compact construction which meets the demand of heat dissipation for high power LED. We also found the heat dissipation performance of the HP heat exchanger changed with the work angle.

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