Search for dissertations about: "void fraction"

Showing result 1 - 5 of 25 swedish dissertations containing the words void fraction.

  2. 1. Plasticity Driven Damage and Void Growth

    Author : Mattias Olsson; Kärnfysik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Termisk teknik; termodynamik; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik; Thermal engineering; applied thermodynamics; vibration and acoustic engineering; vacuum technology; hydraulics; void growth; Mechanical engineering; damage evolution; elasto-plasticity; thermodynamics;

    Abstract : Plasticity induced damage evolution is considered using a thermodynamical approach. Different postulates on how to include the effects of damage in the constitutive equations have been studied. The results reveal that a mapping, similar to that of the stress, of both the kinematic and isotropic hardening variables is to be preferred. READ MORE

  4. 2. Novel Diagnostics and Computational Methods of Neutron Fluxes in Boiling Water Reactors

    Author : John Loberg; Michael Österlund; Thomas Smed; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Void; BWR; neutron fluxes; channel bow; MCNP; 2D 3D; Physics; Fysik;

    Abstract : The focus in this thesis is to improve knowledge of the BWR related uncertainties void, channel bow, and control rods. The presence of void determines the moderation of neutrons in BWRs. A high void fraction is less efficient in moderating neutrons than a low one. READ MORE

  5. 3. Aspects of Sorption Processes in Thermosiphon and in Falling Film Arrangements

    Author : Henrik Kockum; Avdelningen för kemiteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mass transfer; turbulence; falling film; heat transfer; entropy generation; pressure drop; restriction; friction; void fraction; two-phase flow; thermosiphon; sorption; heat pump; model; Chemical technology and engineering; Kemiteknik och kemisk teknologi;

    Abstract : A study concerning closure relations pertinent to the design of sorption equipment of absorption heat pumps has been undertaken. Specifically, thermosiphon and vertical falling film arrangements were studied. READ MORE

  6. 4. Noise Applications in Light Water Reactors with Traveling Perturbations

    Author : Victor Dykin; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Green s function technique; transit times; decay ratio; cross-correlation function; void fraction; global and regional instabilities; propagating density perturbation; BWR stability; reduced order models; non-white driving force; local component; Monte Carlo; space-dependent neutron noise; density wave oscillations;

    Abstract : Neutron noise induced by perturbations traveling with the coolant of light water reactors (LWRs) is investigated. Different methods to simulate the effect of propagating perturbations are considered. The studies are performed in both open- and closed-loop systems and summarized in three chapters. READ MORE

  7. 5. Uncertainty and Sensitivity Analysis Applied to the Validation of BWR Bundle Thermal-Hydraulic Calculations

    Author : Augusto Hernandéz Solís; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Latin Hypercube sampling; uncertainty and sensitivity analysis; Thermal‐hydraulic codes; simple random sampling; reactor safety analysis; BFBT benchmark;

    Abstract : In recent years, more realistic safety analyses of nuclear reactors have been based on best estimate (BE) computercodes. The need to validate and refine BE codes that are used in the predictions of relevant reactor safetyparameters, led to the organization of international benchmarks based on high quality experimental data. READ MORE