Search for dissertations about: "lumped-parameter thermal model"

Found 5 swedish dissertations containing the words lumped-parameter thermal model.

  2. 1. Thermal Analysis and Management of High-Performance Electrical Machines

    Author : Shafigh Nategh; Chandur Sadarangani; Aldo Boglietti; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computational fluid dynamics; directly cooled electric machines; finite element analysis; heat transfer; hybrid electric vehicle; induction machines; lumped-parameter thermal model; permanent-magnet assisted synchronous reluctance machines.;

    Abstract : This thesis deals with thermal management aspects of electric machinery used in high-performance  applications  with  particular  focus put  on electric machines designed for hybrid electric vehicle applications.In the first part of this thesis,  new thermal models of liquid (water and oil) cooled electric machines are proposed. READ MORE

  4. 2. Cooling Strategies for Wave Power Conversion Systems

    Author : Antoine Baudoin; Cecilia Boström; Anne Blavette; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wave power; power conversion system; thermal management; power elctronics; passive cooling; natural convection.;

    Abstract : The Division for Electricity of Uppsala University is developing a wave power concept. The energy of the ocean waves is harvested with wave energy converters, consisting of one buoy and one linear generator. The units are connected in a submerged substation. The mechanical design is kept as simple as possible to ensure reliability. READ MORE

  5. 3. Modelling and Simulation of Reactor Pressure Vessel Failure during Severe Accidents

    Author : Peng Yu; Weimin Ma; Walter Villanueva; Sevostian Bechta; Florian Fichot; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RPV failure; thermo-fluid-structure coupling; creep modelling; melt pool heat transfer; severe accident; CFD; FEA; transIVR;

    Abstract : This thesis aims at the development of new coupling approaches and new models for the thermo-fluid-structure coupling problem of reactor pressure vessel (RPV) failure during severe accidents and related physical phenomena. The thesis work consists of five parts: (i) development of a three-stage creep model for RPV steel 16MND5, (ii) development of a thermo-fluid-structure coupling approach for RPV failure analysis, (iii) performance comparison of the new approach that uses volume loads mapping (VLM) for data transfer with the previous approach that uses surface loads mapping (SLM), (iv) development of a lumped-parameter code for quick estimate of transient melt pool heat transfer, and (v) development of a hybrid coupling approach for efficient analysis of RPV failure. READ MORE

  6. 4. Component and system design of a mild hybrid 48 V powertrain for a light vehicle

    Author : Stefan Skoog; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Extra low voltage; Hybrid Electric Vehicle; 48 V; Li-ion battery; Calorimetric measurement; Oil cooling; Efficiency; Multi-phase; MOSFET; Power Electronics; Permanent Magnet Synchronous Machine; PWM; Inverter; Power density;

    Abstract : This thesis presents contributions in three areas relevant for the development of 48 V mild hybrid electric powertrains for cars. The first part comprises methodologies and extensive testing of lithium-ion battery cells in order to establish the electric and thermal performance using equivalent circuit models. READ MORE

  7. 5. The Effect of Different Perturbations on the Stability Analysis of Light Water Reactors

    Author : Victor Dykin; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; BWR and PWR stability; stability indicators; propagating density perturbation; autocorrelation function; density wave oscillations; decay ratio; non-white driving force; damped harmonic oscillator; reduced order models; Green s function technique;

    Abstract : Neutron noise analysis techniques are studied and developed, with primary useof determining the stability of Boiling Water Reactors (BWRs). In particular, the role ofa specific perturbation prevailing in Light Water Reactors, the propagating densityperturbation, in the stability of BWRs and on the noise field of LWRs in general, isinvestigated by considering three topics. READ MORE