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Job Record #15605
TitleModelling of the pulsating heat pipe
CategoryPhD Studentship
EmployerAtomic Energy Commission (CEA) at Saclay
LocationFrance, Gif Sur Yvette (Paris suburb)
InternationalYes, international applications are welcome
Closure DateMonday, April 01, 2019
Description:
Thermal management of the on-board electronic components becomes one of the 
major issues limiting their power.  Increasingly effective means of transfer 
of heat are required. The Pulsating Heat Pipe (PHP) is a promising solution 
well suitable for the transfer of high powers. The PHP is an extremely 
simple system. Like the conventional heat pipe, it is a closed tube filled 
with a two-phase liquid able to transfer heat from its hot part (evaporator) 
to the cold part (condenser).  The tube is of simple circular section and 
does not need any wick or internal complex structure to ensure the fluid 
motion inside the system. The internal diameter of the tube needs to be 
lower than the capillary length for the working fluid so that the 
alternating liquid plugs and vapor bubbles form inside it. The tube meanders 
between the evaporator and condenser thus firming multiple branches (i.e. 
parallel tubes). It turns out that the self-sustained oscillating motion of 
bubbles and plugs begin in this system when the temperature difference 
between the condenser and evaporator is applied. Such a convective motion 
and caused by it convective heat transfer make PHP extremely efficient with 
respect to other types of heat pipes [1]. However, contrary to them, its 
functioning is non-stationary and thus more difficult to understand and 
model. Since 2007, the CEA has studied PHP both experimentally and 
theoretically [2]. A CASCO simulation code (French abbreviation meaning 
Advanced Code of PHP Simulation) is developed at CEA [3,4]. CASCO correctly 
describes the main operating regimes of PHP which are the continuous 
oscillations and the intermittent oscillations. The first of these regimes 
is very efficient; the performance of PHP in this regime is almost 
independent of the presence of Earth's gravity [5]. In the intermittent 
regime, the performance is worse and declines in the absence of gravity.

The approach used in CASCO is one-dimensional, which allows to describe the 
interaction of dozens of vapor bubbles. CASCO is based on a simple model of 
liquid films whose thickness is constant and the length is controlled by the 
film evaporation [6]. This model, however, contradicts the recent 
experimental data obtained in the framework of L. Fourgeaud's thesis [7-8]. 
This project aims to achieve three goals. First, it will be necessary to 
develop a more appropriate film model. This new model will be studied in the 
simplest geometries (single-branch PHP, U-turn PHP) to validate it by 
comparing with existing experimental data. This model will then be used in 
CASCO to describe multi-branch PHPs. The second objective of the thesis is 
to study the nonlinear liquid plug dynamics. The PhD student will study the 
collective behavior of liquid plugs and its impact on the dynamic transition 
between PHP operating regimes. The third objective is the validation of 
CASCO by simulation of the experiments of other research groups 
collaborating with the CEA, in particular, its partners within the ESA Space 
PHP project such as the Pprime Institute (ENSMA / Poitiers), University of 
Pisa (Italy), University of Brighton (UK) ... In this project, we take 
advantage of the absence of gravity to increase the diameter of the tube 
(which will remain capillary) and thus reduce the viscous energy losses. The 
PhD student will therefore participate in the Space PHP project; its 
prototype is planned to be implemented on the ESA Heat Transfer Host 1 
facility onboard the International Space Station.

The PhD student will be based at the Saclay Center of the Alternative 
Energies and Atomic Energy Commission of France (CEA), at the Laboratory of 
Condensed Matter Physics (SPEC) (SPEC) within the group of physical systems 
out of equilibrium, hydrodynamics, energy, and complexity (SPHYNX). The PhD 
student will benefit from the infrastructure and research environment of the 
Paris-Saclay University. The PhD student will be enrolled at the Doctoral 
School 564 EDPIF.

Thesis director: Vadim Nikolayev

Desirable knowledge and skills:
Fluid physics and fluid mechanics, heat transfer, nonlinear dynamics. 
Knowledge of numerical methods and programming with C++ are desirable. 
Acquaintance with Microsoft Visual Studio and object oriented programming 
will be a plus. A publication or internship abroad is required for the 
international candidates.
References
1.	Marengo, M. & Nikolayev, V. Pulsating Heat Pipes: Experimental 
Analysis, Design and Applications, In: Encyclopedia of Two-Phase Heat 
Transfer and Flow IV, Thome, J. R. (ed.), ISBN: 978-981-3234-36-9, vol. 1, 
Modeling of Two-Phase Flows and Heat Transfer, World Scientific, 2018, pp. 1 
- 62.
2.	Nikolayev, V. & Marengo, M. Pulsating Heat Pipes: Basics of 
Functioning and Numerical Modeling, In: Encyclopedia of Two-Phase Heat 
Transfer and Flow IV, Thome, J. R. (ed.), ISBN: 978-981-3234-36-9, vol. 1, 
Modeling of Two-Phase Flows and Heat Transfer, World Scientific, 2018, pp. 
63 - 139.
3.	Nikolayev, V.S. A Dynamic Film Model of the Pulsating Heat Pipe, J. 
Heat Transfer, ASME, 2011 Vol. 133 (8), 081504.
4.	Nekrashevych, I. & Nikolayev, V. S. Effect of tube heat conduction 
on the pulsating heat pipe start-up, Appl. Therm. Eng., 2017 vol. 117, 24 – 
29.

Contact Information:
Please mention the CFD Jobs Database, record #15605 when responding to this ad.
NameVadim Nikolayev
Emailvadim.nikolayev@cea.fr
Email ApplicationYes
Phone+33169089488
URLhttp://iramis.cea.fr/Pisp/vadim.nikolayev/
AddressService de Physique de l'Etat Condensé
Bât 772, Orme des Merisiers
CEA Saclay
91191 Gif sur Yvette Cedex
France
Record Data:
Last Modified12:36:21, Friday, January 18, 2019

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