Three dimensional liquid and vapor distribution in the wick of capillary evaporators

Heat and mass transfer with liquid–vapour phase change in a representative unit cell of a capillary evaporator is studied using a mixed pore network model. The model combines the computation of temperature and pressure fields in vapour and liquid pores according to mean field approaches with pore scale invasion rules depending on the capillary pressure thresholds associated with each local constriction between two pores. The metallic body through which heat is transferred to the porous wick is also taken into account in the simulations. After comparisons with a visualisation experiment, numerical simulations performed in three dimensional pore networks lead to the identification of three main regimes depending on the applied heat load. Compared with previous works using the so-called vapour pocket assumption, the 3D simulations reveal a regime where the phase distribution within the wick is fundamentally different. This regime is characterised by the coexistence of both the liquid and vapour phases underneath the casing within the wick. This regime is shown to correspond to the best evaporator performance

Three dimensional heat and mass transfer in capillary evaporator

Heat and mass transfer inside the porous wick of a capillary evaporator is studied using a mixed porenetwork model. The impact of the thermal conductivity of the wick on the overheating limit (defined as the difference between the maximum temperature at the top of the metallic casing and the saturated temperature), breakthrough (which occurs when the vapor reaches the wick inlet) and the parasitic heat flux lost by conduction at the entrance of the wick (which decreases the efficiency of the evaporator) is investigated. The study suggests a bilayer wick as a possible better design to optimize the performance of the evaporator. With this design, the inlet layer is of low thermal conductivity with small pore size so as to reduce the parasitic heat flux. The inlet layer also plays a role of capillary lock limiting the risk of breakthrough. The second layer, right under the metallic casing, is more conductive with a high thermal conductivity and larger pores so as to .limit the risk of overheating. It is shown that this design increases the range of heat loads which can be applied to the evaporator

Heat and Mass Transfer in the Porous Wick of a Capillary Evaporator

Heat and mass transfer inside the porous wick of a capillary evaporator is studied using a mixed pore-network model. The impact of the thermal conductivity of the wick on the overheating limit (defined as the difference between the maximum temperature at the top of the metallic casing and the saturated temperature), breakthrough (which occurs when the vapor reaches the wick inlet) and the parasitic heat flux lost by conduction at the entrance of the wick (which decreases the efficiency of the evaporator) is investigated. The study suggests a bilayer wick as a possible better design to optimize the performance of the evaporator. With this design, the inlet layer is of low thermal conductivity with small pore size so as to reduce the parasitic heat flux. The inlet layer also plays a role of capillary lock limiting the risk of breakthrough. The second layer, right under the metallic casing, is more conductive with a high thermal conductivity and larger pores so as to limit the risk of overheating. It is shown that this design increases the range of heat loads which can be applied to the evaporator.Comment: Proceedings of the 5th International Conference on Porous Media and its Applications in Science and Engineering (ICPM5), June 22-27, 2014, Kona, Hawaii, U

Incarcerated Minors and Their Health: The Lack of Data and the Risk of Institutional Stigmatization

International audienc

A follow-up study on the quality of alcohol dependence-related information on the web

In order to evaluate the one-year evolution of web-based information on alcohol dependence, we re-assessed alcohol-related sites in July 2007 with the same evaluating tool that had been used to assess these sites in June 2006. Websites were assessed with a standardized form designed to rate sites on the basis of accountability, presentation, interactivity, readability, and content quality. The DISCERN scale was also used, which aimed to assist persons without content expertise in assessing the quality of written health publications. Scores were highly stable for all components of the form one year later (r = .77 to .95, p < .01). Analysis of variance for repeated measures showed no time effect, no interaction between time and scale, no interaction between time and group (affiliation categories), and no interaction between time, group, and scale. The study highlights lack of change of alcohol-dependence-related web pages across one year

Benoît Garnot, C’est la faute à Voltaire… Une imposture intellectuelle ?

Depuis 1995, Benoît Garnot a publié d’importantes études sur l’histoire de la France moderne et, notamment, sur la justice d’Ancien Régime. C’est dans le droit fil de ses travaux sur les structures de l’appareil judiciaire qu’il présente ici son analyse du rôle éminent joué par Voltaire dans la mise en forme de la « légende noire » de cette institution. Le titre, dans sa problématique, place d’emblée cet ouvrage dans le champ de la polémique, sinon même dans celui du pamphlet historique. Et l..