Key features of the THESEUS-FE® Thermal Solver

Key features of the THESEUS-FE thermal solver



Implicit solver technology

Fig. 1: Implicit solver
technology

Finite Elements

Fig. 3: Finite Elements

Air/Vacuum Layers

Fig. 5: Air/Vacuum
Layers

Solid Finite Elements

Fig. 7: Solid Finite Elements

Automatic T-Stub Handling

Fig. 9: Automatic T-Stub
Handling

Fiala's manikin with active mode simulations

Fig. 11: Fiala's manikin with
active mode simulations

Structure elements

Fig. 13: Structure elements

Sector-wise clothing insulation

Fig. 15: Sector-wise
clothing insulation

Boundary conditions on groups

Fig. 17: Boundary
conditions on groups

View Factor

Fig. 19: View Factor

Example Model BMW X3

Fig. 21: Example Model
BMW X3

Refraction

Fig. 24: Refraction

Diffusive solar radiation and ground<br>reflection

Fig. 26: Diffusive solar
radiation and ground
reflection

Contact boundary conditions

Fig. 28: Contact boundary
conditions

Transmittance for diffusive radiation

Fig. 30: Transmittance for
diffusive radiation

HDF files

Fig. 2: HDF files

Shell elements

Fig. 4: Shell elements

Influence of meshing

Fig. 6: Influence of
meshing

1D-Elements

Fig. 8: 1D-Elements

Airzone

Fig. 10: Airzone

Bio-Heat-Equatation

Fig. 12: Bio-Heat-
Equatation

Metabolic system

Fig. 14: Metabolic
system

Local thermal comfort prediction

Fig. 16: Local thermal
comfort prediction

Element-wise parameters

Fig. 18: Element-wise
parameters

Ray tracing with Space Partitioning

Fig. 20: Ray tracing
with Space Partitioning

Moving sun simulation

Fig. 22: Moving sun
simulation

Radiation properties of glasses

Fig. 23: Radiation
properties of glasses

Sky temperature prediction

Fig. 25: Sky temperature
prediction

Advanced Convection Laws

Fig. 27: Advanced
Convection Laws

Atmospheric Sky Radiation

Fig. 29: Atmospheric
Sky Radiation

General

  1. Available for Windows & Linux (32/64-Bit)
  2. Implicit solver technology (Backw. Euler & Crank Nicolson available), see Fig. 1
  3. Transient & steady state solutions
  4. Conduction solver based on iterative cg scheme (using matrix pre-conditioning)
  5. Radiation solver based on iterative Gauss-Seidel scheme
  6. Solver reads in controlling keywords from ASCII files (elements & grids in NASTRAN format)
  7. Solver writes out binary HDF1 files containing all relevant post data (geometry, scalar & field results), see Fig. 2
  8. Comprehensive validations and automatic testing routines (QM) guaranties maximum result quality
  9. Fixed & Adaptive time stepping
  10. Restart analysis available
  11. Automatic solution damping and time step reduction in case of divergence

Conductive Structure Finite Elements (FE)

  1. Supported NASTRAN elements: HEXA, PENTA, TETRA, QUAD, TRIA, BAR, RBE2/3, ..., see Fig. 3
  2. Multi-layered composite shell elements with 3D or 1D conduction, see Fig. 4
  3. Air-/vacuum layers in shells (considering internal radiation/convection), see Fig. 5
  4. Accurate solutions for pure Tria meshes and bad-shaped FE, see Fig. 6
  5. All kinds of solid elements with grid-wise solutions, see Fig. 7
  6. 1D-elements: conduction through BARs and via Multi-Point-Constraints (MPC), see Fig. 8
  7. Anisotropic heat conduction
  8. Temperature dependent material properties
  9. Automatic T-stub handling for shell elements, see Fig. 9

Volumes, Airzones and Ventilations

  1. Volumes are user-defined fluid or gas regions with temperature dependent properties
  2. Airzones are pre-defined regions with 2 degree of freedom: temperature & humidity
  3. User-defined mass fow rates between Airzones & Volumes
  4. Standard Ventilations define mass flow rates with given temperatures into Airzones, see Fig. 10
  5. Inverse Mode Ventilations solve for inlet temperatures at given Airzone temperature functions, see Fig. 10
  6. Coupled solutions for convective heat transfer between FE and Airzones/Volumes

Thermal Manikin FIALA-FE

  1. Fully realizes Dusan Fiala's manikin, as presented in his PhD thesis, see Fig. 11
  2. Uses special finite elements that apply the Bio-Heat-Equation, see Fig. 12
  3. Unlimited number of manikins, user defined level of discretization
  4. Fully coupled with Structure Elements (or uncoupled simulations with sector-wise b.c.), see Fig. 13
  5. Passive mode simulations to derive thermal neutrality
  6. Active mode simulations (includes sweating, shivering, vasomotion), see Fig. 11
  7. Body element sectors conduct heat via finite elements
  8. Blood circulation fully coupled with the metabolic system
  9. Metabolic system considering user-defined activity levels and shivering, see Fig. 14
  10. Respiration and evaporation coupled with Airzones via heat and mass transfer
  11. Sector-wise clothing insulation, see Fig. 15
  12. Different kinds of global thermal comfort indices: PMV, TS, DTS, global heat flux balance
  13. Local thermal comfort prediction based on local equivalent temperatures, see Fig. 16

Boundary Conditions

How to define Boundary Conditions

  1. The user typically defines boundary conditions on groups of shell elements as (see Fig. 17)
    • fixed parameters
    • time-dependent functions
    • temperature-dependent functions
  2. Element-wise parameters can be considered ... (see Fig. 18)
    • reading boundary conditions from ASCII files
    • automatic result file mapping (inter- & extrapolation)
    • by programming User-Subroutines
    • using TISC2 (in a coupled simulation)

Radiation Boundary Conditions

  1. Models for long-wave and short-wave radiation, see Fig. 29
  2. Black body & grey body radiation (considering diffusive reflection), see Fig. 19
  3. Surface-to-surface view factor calculation, see Fig. 19
  4. High speed ray tracing uses kd-tree data structures for view factor shading and parallel radiators, see Fig. 20
  5. Compressed view factor matrix storage
  6. Automatic patching helps to minimize view factor matrices, see Fig. 21
  7. Temperature dependent surface emissivity
  8. Moving sun with direct and diffusive radiation, see Fig. 22
  9. Glass transmittance through windows dep. on the angle of incidence (for diffusive/direct sun), see Fig. 23
  10. Refraction in glasses, see Fig. 24
  11. Automatic sky temperature prediction on cloudness and given air temperature/humidity, see Fig. 25
  12. Diffusive sun from sky and ground reflection, see Fig. 26
  13. Models for diffuse transmittance through glasses, depending on effective incidence angles, see Fig. 30

Convective Boundary Conditions

  1. Forced convection for laminar & turbulent flow: analytic relations for heat transfer coeff. from given fluid temperatures and velocities, see Fig. 27
  2. Free convection: analytic relations for heat transfer coefficient for the arbitrary inclined plate, see Fig. 27
  3. Element-wise heat transfer coefficient and fluid temperatures from ASCII files
  4. Temperature dependent fluid properties

Contact Boundary Conditions

  1. Automatic contact search algorithms, within a user-def. distance, see Fig. 28
  2. Tied contact, based on automatically created multi-point-constraints, see Fig. 28
  3. Conductive contacts (conductivity might depend on user-def. parameters and distance), see Fig. 28

Further Boundary Conditions

  1. Applied fluxes on outer surfaces
  2. Fixed/driven temperature boundary conditions
  3. Internal heat generation in shell layers


 

1 HDF = Hierarchical Data Format
2 TISC = TLK Inter Software Connector, http://www.tlk-thermo.com/tisc.html