CFD modeling of flow and heat transfer in a thermosyphon

Alizadehdakhel, Asghar; Rahimi, Masoud; Alsairafi, Ammar Abdulaziz

doi:10.1016/j.icheatmasstransfer.2009.09.002

Cited by 297 publications

(60 citation statements)

References 19 publications

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“…They used similar thermosyphon configurations to that of Amatachaya et al [12] to validate their simulation model, and an Eulerian model to simulate the film condensation at the condenser zone, with a filling ratio of 30% of the evaporator zone. Alizadehdakhel et al [13] focused on a two-dimensional model simulation and experimental studies, in which they investigated the effect of the input heat flow and the filling ratio of the working fluid on the performance of a two-phase closed thermosyphon, using water as a working fluid. Zhang et al [14] developed a two-dimensional model of a diskshaped flat two-phase thermosyphon used for electronics cooling.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional CFD simulation of geyser boiling in a two-phase closed thermosyphon

Jouhara

Fadhl

Wrobel

2016

International Journal of Hydrogen Energy

109

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This paper examines the application of CFD modelling to simulate the complex multiphase characteristics inside a wickless heat pipe (thermosyphon). Water and refrigerant R134a were selected as working fluids. A novel and comprehensive threedimensional CFD model of a wickless heat pipe was developed to simulate both the complex multiphase heat and mass transfer characteristics of boiling and condensation and the heat transfer characteristics of the cooling fluid in the condenser -heat exchanger. The CFD simulation has successfully predicted, for the first time, a boiling regime and two phase flow pattern that takes place with water at low power throughput, known as geyser boiling. The effects of the power throughput on the characteristics of the geyser boiling were investigated. The CFD simulation was also successful in modelling and visualising the multiphase flow characteristics, emphasising the difference in pool boiling behaviour between these working fluids.Temperature profiles and visual validation of the resulting 3D CDF findings were conducted using two experimental facilities.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional CFD simulation of geyser boiling in a two-phase closed thermosyphon

Jouhara

Fadhl

Wrobel

2016

International Journal of Hydrogen Energy

109

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“…A wickless heat pipe, or a two-phase closed thermosyphon, relies on gravitational forces to return the working fluid to the evaporator. This is different from a wicked heat pipe, where the working fluid is returned from the condenser by capillary forces [1][2][3][4]. Heat pipes have been successfully used for waste heat energy recovery in a vast range of engineering applications, such as heating, ventilation, and air conditioning (HVAC) systems [5], ground source heat pumps [6], water heating systems [7] and electronics thermal management [8].…”

Section: Introductionmentioning

confidence: 99%

“…However, only a limited number of CFD numerical simulation studies on two-phase closed thermosyphons have been published. Alizadehdakhel et al [1] provided a two-dimensional model and experimental studies in which they investigated the effect of input heat flow and fill ratio of the working fluid on the performance of a two-phase closed thermosyphon. They validated their study using experimental results.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of the temperature distribution in a two-phase closed thermosyphon

Fadhl

Wrobel

Jouhara

2013

Applied Thermal Engineering

243

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A B S T R A C TInterest in the use of heat pipe technology for heat recovery and energy saving in a vast range of engineering applications has been on the rise in recent years. Heat pipes are playing a more important role in many industrial applications, particularly in improving the thermal performance of heat exchangers and increasing energy savings in applications with commercial use. In this paper, a comprehensive CFD modelling was built to simulate the details of the twophase flow and heat transfer phenomena during the operation of a wickless heat pipe or thermosyphon, that otherwise could not be visualised by empirical or experimental work. Water was used as the working fluid. The volume of the fluid (VOF) model in ANSYS FLUENT was used for the simulation. The evaporation, condensation and phase change processes in a thermosyphon were dealt with by adding a user-defined function (UDF) to the FLUENT code. The simulation results were compared with experimental measurements at the same condition. The simulation was successful in reproducing the heat and mass transfer processes in a thermosyphon. Good agreement was observed between CFD predicted temperature profiles and experimental temperature data.

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“…The study on the heat transfer coefficient indicated that nucleate boiling is the dominant mechanism in large pipes at low mass and heat flux, with the heat transfer coefficient being less sensitive to the total mass flux. Alizadehdakhel et al [19] simulated the wall temperature of a two-phase closed thermosyphon as the different fill ratios and inlet heat flow change by using the VOF model, the result of which was widely cited [20,21]. However, GUO et al [14] developed the volume of fluid level set (VOSET) method which combined the advantages of both VOF and level set methods to simulate a onedimensional Stefan problem, two-dimensional horizontal film boiling, and horizontal film boiling of water at near critical pressure.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Vapor-Liquid Two-Phase Flow of Evaporation and Condensation

Hong-jie¹,

Zhang²,

Li³

et al. 2016

IJHT

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The heat pipe receiver with integrated high temperature latent thermal energy storage is one of the key components of Solar Dynamic Space Power System (SDPSS), among which the evaporation and condensation is the main heat transfer mode, a very complicated two-phase flow. However, research on the two-phase flow and heat transfer characteristics is an effective way to improve the system efficiency and reduce the system mass. So a two-dimensional physical model was built and the volume of fluid (VOF) technique was used to model the interaction between the two phases. The UDF (Users Define Function) was introduced to handle the mass source terms. In the study, the relationship between superheat, subcooling and wall heat flux were investigated. In addition, the flow pattern of bubbles in the tube was analyzed. Compared with the churn bubbles flow, the heat transfer coefficient of the bubbles flow was much higher. Bubble departure diameter increased as surface subcooling increased. The work in this paper lays a good foundation for the further research on the heat transfer characteristics of heat pipe receiver with integrated high temperature latent thermal energy storage.

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CFD modeling of flow and heat transfer in a thermosyphon

Cited by 297 publications

References 19 publications

Three-dimensional CFD simulation of geyser boiling in a two-phase closed thermosyphon

Three-dimensional CFD simulation of geyser boiling in a two-phase closed thermosyphon

Numerical modelling of the temperature distribution in a two-phase closed thermosyphon

Simulation of the Vapor-Liquid Two-Phase Flow of Evaporation and Condensation

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