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Ken U Snowden - One of the best experts on this subject based on the ideXlab platform.

  • a strain Energy Density method for the prediction of creep fatigue damage in high temperature components
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010
    Co-Authors: Warwick M Payten, David W Dean, Ken U Snowden
    Abstract:

    Abstract The accumulation of creep–fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model has been developed that assumes on a macroscopic level that the Energy dissipated in the material may be taken as a measure of the creep damage induced in the material and hence the creep damage is directly proportional to absorbed Internal Energy Density. The model developed is derived from considerations of mechanistic cavity growth and is based on rupture elongation to failure data using true strain. The predictions of the Energy Density exhaustion approach are compared with the results of creep–fatigue tests on low alloy ferritic steels. The predicted results of the Energy Density model are found to have good correlation with the measured creep–fatigue lives.

  • A strain Energy Density method for the prediction of creep–fatigue damage in high temperature components
    Materials Science and Engineering: A, 2010
    Co-Authors: Warwick M Payten, David W Dean, Ken U Snowden
    Abstract:

    The accumulation of creep–fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model has been developed that assumes on a macroscopic level that the Energy dissipated in the material may be taken as a measure of the creep damage induced in the material and hence the creep damage is directly proportional to absorbed Internal Energy Density. The model developed is derived from considerations of mechanistic cavity growth and is based on rupture elongation to failure data using true strain. The predictions of the Energy Density exhaustion approach are compared with the results of creep–fatigue tests on low alloy ferritic steels. The predicted results of the Energy Density model are found to have good correlation with the measured creep–fatigue lives. © 2010, Elsevier Ltd

  • A strain Energy Density method for the prediction of creep–fatigue damage in high temperature components
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Warwick M Payten, David W Dean, Ken U Snowden
    Abstract:

    Abstract The accumulation of creep–fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model has been developed that assumes on a macroscopic level that the Energy dissipated in the material may be taken as a measure of the creep damage induced in the material and hence the creep damage is directly proportional to absorbed Internal Energy Density. The model developed is derived from considerations of mechanistic cavity growth and is based on rupture elongation to failure data using true strain. The predictions of the Energy Density exhaustion approach are compared with the results of creep–fatigue tests on low alloy ferritic steels. The predicted results of the Energy Density model are found to have good correlation with the measured creep–fatigue lives.

Sauro Succi - One of the best experts on this subject based on the ideXlab platform.

  • Simulating two-dimensional thermal channel flows by means of a lattice Boltzmann method with new boundary conditions
    Future Generation Computer Systems, 2004
    Co-Authors: Annunziata D’orazio, Sauro Succi
    Abstract:

    Thermal boundary conditions for a doubled-populations BGK model are introduced and numerically demonstrated. The unknown thermal distribution functions at the boundary are assumed to be equilibrium distribution functions, with a counter-slip Internal Energy Density which is determined consistently with Dirichlet and/or Neumann boundary constraints. The hydrodynamic boundary conditions are adapted to situations of engineering interest, and viscous heating effects are taken in account. The method is used to simulate channel flows; numerical results and theoretical solutions are found in satisfactory agreement for both hydrodynamic and thermal fields.

  • International Conference on Computational Science - Boundary conditions for thermal lattice Boltzmann simulations
    Lecture Notes in Computer Science, 2003
    Co-Authors: Annunziata D’orazio, Sauro Succi
    Abstract:

    A boundary condition for temperature and heat flux of a thermal lattice Boltzmann method is presented. A thermal lattice BGK model with doubled populations is used to simulate hydrodynamic and thermal fields for flows with viscous heating. The unknown thermal distribution functions at the boundary are assumed to be equilibrium distribution functions with a counter-slip Internal Energy Density which is determined consistently with Dirichlet and/or Neumann boundary conditions.

Annunziata D’orazio - One of the best experts on this subject based on the ideXlab platform.

  • Lattice Boltzmann method with heat flux boundary condition applied to mixed convection in inclined lid driven cavity
    Meccanica, 2014
    Co-Authors: Annunziata D’orazio, Arash Karimipour, Alireza Hossein Nezhad, Ebrahim Shirani
    Abstract:

    Mixed convection in a inclined cavity has not been investigated by LBM in case of an imposed non zero heat flux. This type of boundary condition, representing very usual situations in physical world, is not simple to model in lattice Boltzmann schemes. In effect, the only boundary condition able to simulate an imposed temperature and an imposed heat flux at a boundary has been presented by D’Orazio et al. in previous works, where the boundary was at rest. In this work, laminar mixed convective heat transfer in two-dimensional rectangular inclined driven cavity is studied numerically by means of a double population thermal Lattice Boltzmann method. The counter-slip Internal Energy Density boundary condition, able to simulate an imposed heat flux at the wall, is applied. Through the top moving lid the heat flux enters the cavity and it leaves the system through the bottom wall; side walls are adiabatic. Results are analyzed over a range of the Richardson numbers and tilting angles of the enclosure, encompassing the dominating forced convection, mixed convection, and dominating natural convection flow regimes. The results show that, as expected, heat transfer rate increases as increases the inclination angle, but this effect is significant for higher Richardson numbers, when buoyancy forces dominate the problem; for horizontal cavity, average Nusselt number decreases with the increase of Richardson number because of the stratified field configuration. This study shows that the counter-slip Internal Energy Density boundary condition can be effectively used to simulate heat transfer phenomena also in case of moving walls and it makes the Lattice Boltzmann Method able to simulate a wide class of cooling process where a given thermal power must be removed.

  • Simulating two-dimensional thermal channel flows by means of a lattice Boltzmann method with new boundary conditions
    Future Generation Computer Systems, 2004
    Co-Authors: Annunziata D’orazio, Sauro Succi
    Abstract:

    Thermal boundary conditions for a doubled-populations BGK model are introduced and numerically demonstrated. The unknown thermal distribution functions at the boundary are assumed to be equilibrium distribution functions, with a counter-slip Internal Energy Density which is determined consistently with Dirichlet and/or Neumann boundary constraints. The hydrodynamic boundary conditions are adapted to situations of engineering interest, and viscous heating effects are taken in account. The method is used to simulate channel flows; numerical results and theoretical solutions are found in satisfactory agreement for both hydrodynamic and thermal fields.

  • International Conference on Computational Science - Boundary conditions for thermal lattice Boltzmann simulations
    Lecture Notes in Computer Science, 2003
    Co-Authors: Annunziata D’orazio, Sauro Succi
    Abstract:

    A boundary condition for temperature and heat flux of a thermal lattice Boltzmann method is presented. A thermal lattice BGK model with doubled populations is used to simulate hydrodynamic and thermal fields for flows with viscous heating. The unknown thermal distribution functions at the boundary are assumed to be equilibrium distribution functions with a counter-slip Internal Energy Density which is determined consistently with Dirichlet and/or Neumann boundary conditions.

Warwick M Payten - One of the best experts on this subject based on the ideXlab platform.

  • a strain Energy Density method for the prediction of creep fatigue damage in high temperature components
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2010
    Co-Authors: Warwick M Payten, David W Dean, Ken U Snowden
    Abstract:

    Abstract The accumulation of creep–fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model has been developed that assumes on a macroscopic level that the Energy dissipated in the material may be taken as a measure of the creep damage induced in the material and hence the creep damage is directly proportional to absorbed Internal Energy Density. The model developed is derived from considerations of mechanistic cavity growth and is based on rupture elongation to failure data using true strain. The predictions of the Energy Density exhaustion approach are compared with the results of creep–fatigue tests on low alloy ferritic steels. The predicted results of the Energy Density model are found to have good correlation with the measured creep–fatigue lives.

  • A strain Energy Density method for the prediction of creep–fatigue damage in high temperature components
    Materials Science and Engineering: A, 2010
    Co-Authors: Warwick M Payten, David W Dean, Ken U Snowden
    Abstract:

    The accumulation of creep–fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model has been developed that assumes on a macroscopic level that the Energy dissipated in the material may be taken as a measure of the creep damage induced in the material and hence the creep damage is directly proportional to absorbed Internal Energy Density. The model developed is derived from considerations of mechanistic cavity growth and is based on rupture elongation to failure data using true strain. The predictions of the Energy Density exhaustion approach are compared with the results of creep–fatigue tests on low alloy ferritic steels. The predicted results of the Energy Density model are found to have good correlation with the measured creep–fatigue lives. © 2010, Elsevier Ltd

  • A strain Energy Density method for the prediction of creep–fatigue damage in high temperature components
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Warwick M Payten, David W Dean, Ken U Snowden
    Abstract:

    Abstract The accumulation of creep–fatigue damage over time is the principal damage mechanism which will eventually lead to crack initiation in critical high temperature equipment. A model has been developed that assumes on a macroscopic level that the Energy dissipated in the material may be taken as a measure of the creep damage induced in the material and hence the creep damage is directly proportional to absorbed Internal Energy Density. The model developed is derived from considerations of mechanistic cavity growth and is based on rupture elongation to failure data using true strain. The predictions of the Energy Density exhaustion approach are compared with the results of creep–fatigue tests on low alloy ferritic steels. The predicted results of the Energy Density model are found to have good correlation with the measured creep–fatigue lives.

Gary D Doolen - One of the best experts on this subject based on the ideXlab platform.

  • a novel thermal model for the lattice boltzmann method in incompressible limit
    Journal of Computational Physics, 1998
    Co-Authors: Shiyi Chen, Gary D Doolen
    Abstract:

    A novel lattice Boltzmann thermal model is proposed for studying thermohydrodynamics in incompressible limit. The new model introduces an Internal Energy Density distribution function to simulate the temperature field. The macroscopic Density and velocity fields are still simulated using the Density distribution function. Compared with the multispeed thermal lattice Boltzmann models, the current scheme is numerically more stable. In addition, the new model can incorporate viscous heat dissipation and compression work done by the pressure, in contrast to the passive-scalar-based thermal lattice Boltzmann models. Numerical simulations of Couette flow with a temperature gradient and Rayleigh?Benard convection agree well with analytical solutions and benchmark data.