This thesis presents a model for predicting the forced convective critical heat flux (CHF) for water over a wide range of thermal-hydraulic conditions which might be encountered during normal and accident operations of a light water nuclear reactor. The model is primarily composed from existing steady-state CHF correlations for tubes or tube and rod bundle geometries, and encompasses the following parametric ranges: 0.3 ≤ P (MPa) ≤ 16.0 6.0 ≤ D (mm) ≤ 30.0 100.0 ≤ G (kg/m2s) ≤ 8000.0 -0.30 ≤ X ≤ 1.0 The correlations used as the foundation of this model are the 1) Westinghouse-3 2) Biasi correlation, and the 3) Modified Barnett correlation The mode 1 presented is comp a red with available data, and the resultant model is illustrated as a 3-D surface in mass flux, quality, and CHF space to represent general CHF behavior.

Différentes techniques de chirurgie mini-invasive permettent aujourd’hui d’effectuer les procédures d'ablation de tumeurs. La cryochirurgie est une de ces techniques et fonctionne grâce à une technique de décompression très rapide de l'argon à l’extrémité d’une sonde en forme d'aiguille. La planification pré-opératoire de ce type d’intervention est très difficile pour le chirurgien, qui doit se représenter mentalement la disposition finale des aiguilles par rapport à la position des structures anatomiques complexe. Une sur-ablation ou une sous-ablation peuvent entraîner des complications donc, devant le besoin crucial d'une telle planification, dans cette thèse nous nous sommes concentrés sur la planification pré-opératoire automatisée de la cryochirurgie,avec les objectifs de assister le chirurgien grâce à une prédiction plus réaliste des zones d'ablation et proposer automatiquement un placement d'aiguille avec un risque minimal pour le patient dans un délai acceptable pour une utilisation en salle d'opération. / There exist several minimally invasive techniques to perform tumor ablation procedures.Cryosurgery is one of these techniques and works by decompressing very rapidly the argon gas through a needle-like probe. It is hard for the surgeons to imagine final results and plan the surgery in advance in a complicated anatomical environment. Over-ablation or under ablation may result in complications during the treatment. So, due to a crucial need for having such a planning tool, in this thesis we focused on an automated pre-surgical planning for cryosurgery with goals to support the physician by utilizing a more realistic prediction of ablation zones and proposing a needle placement setup with a close to minimum risk to the patient and an optimal coverage of the tumor by the iceball in an acceptable time for the use in the operation room.

The diploma thesis deals with the simulation of heat dissipation for LED Seoul SZ5-P. The heat transfer is discussed first. Further, the issue of thermal management and its design is analyzed. The dependence of LED junction temperature on area of single and double layer printed circuit board is simulated with Ansys Icepak. Additionally, influences of the number and placement of vias on the printed circuit board and aluminum substrate printed circuit board are simulated. Last but not least, the equations describing the dependence of printed circuit board area on desired LED junction temperature are derived. Finally, the values of heat transfer coefficient including convection and radiation are determined for various heat losses and junction temperatures.

To decrease the ecological footprint, humans either have to adjust their lifestyles, or the large scale industries must take corporate social responsibility. This study is based on the well-developed field of energy efficiency in industries by applying technology and organizational-focused proposals. The proposals are based on three different aspects, the economic, the environmental, and the social. These three aspects combined are called the triple bottom line perspective. An original case of the study objects energy balance was determined to develop the conclusions, with the simulation program IDA ICE. The study object was GKN ePowertrain, located in Köping. Energy efficiency cases were simulated in IDA ICE to observe the change in the energy balance. The cases and interviews of the employees were the foundation of the discussion where the improvements were critically reviewed from the triple bottom line perspective. The result shown that the temperature was too high for working conditions, the ventilation system consumes a large quantity of energy, and the internal flow of information is insufficient. In conclusion, GKN ePowertrain would increase their overall value by investing in a cooling system and more efficient heat exchangers for their ventilation system. These investments would notably increase their short term value of environmental sustainability and the social aspect. Furthermore, their economic value would increase in the long term. The cooling system would improve the working environment, and a new ventilation system would increase the heat recovery and decrease the energy consumed, even more than the consumption of the cooling system. Finally, GKN should also be more distinct in their information to the employees in the building regarding energy aims and their working environment, to have a positive gain of value in all the fields.