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Thermal Solver
Contains thermal solver related guides, such as the TMG reference manual, thermal API guide, and error message list.
Thermal solver theory
Describes the theory and methods of the thermal solver.
Solar heating
Two methods for solar flux calculations
Comparison of solar radiation calculation methods
This table compares two solar flux calculation methods in thermal simulations: one based on atmospheric extinction coefficients, and another based on altitude and turbidity.

Thermal Solver
Contains thermal solver related guides, such as the TMG reference manual, thermal API guide, and error message list.
- Thermal solver guides
  Maya HTT's thermal solver is included in Simcenter 3D and in Simcenter Femap. This page contains links to thermal solver guides, which help you understand how the thermal solver works.
- Thermal solver reference
  Describes the format and contents of the thermal solver's input and output files
- Thermal solver theory
  Describes the theory and methods of the thermal solver.
  - Introduction
    This guide provides the theory and methods used by the thermal solver, including methods to calculate conduction, convection, and radiation, as well as modeling specific topics using the thermal solver.
  - Elements in the thermal solver
    The thermal solver uses elements to calculate conductive, convective, and radiative conductances, as well as hydraulic resistances.
  - Supported element types for radiation
    Radiating elements may be defined with 1 to 4 corner nodes. The elements may be linear or parabolic.
  - Conduction methods
    To model heat conduction, the thermal solver can use two finite volume methods, center of element method or element's center of gravity method, or the finite element method.
  - Convective heat transfer methods
    The thermal solver computes convection conductances for various geometrical configurations using correlations that depend on specified characteristic lengths, convective surfaces, and type of convection.
  - Radiation exchange
    Thermal radiation is a heat transfer due to electromagnetic radiation emitted by the surface of bodies due to their temperature.
  - Solar heating
    - Factors influencing solar heat flux
      The interaction of solar radiation with the Earth's atmosphere and surface is governed by three main groups of factors that influence solar heating in thermal models, including geometric, terrain, and atmospheric effects.
    - Solar radiation components
      Solar radiation reaching the Earth's surface is composed of three main components.
    - Two methods for solar flux calculations
      - Solar radiation calculation using the atmospheric extinction coefficient
        The thermal solver computes solar flux by modeling direct, diffuse, and reflected radiation components using the atmospheric extinction coefficient.
      - Solar radiation calculation using altitude and turbidity
        The thermal solver computes solar flux by modeling direct, diffuse components as a function of altitude and turbidity.
      - Comparison of solar radiation calculation methods
        This table compares two solar flux calculation methods in thermal simulations: one based on atmospheric extinction coefficients, and another based on altitude and turbidity.
    - Computing radiation under overcast conditions
      To compute the overcast irradiance from clear-sky raster maps, the thermal solver uses a correction factor that accounts for cloud cover attenuation.
    - Explicit sky and ground modeling
      The thermal solver explicitly models ground geometry for solar flux and shadowing calculations.
  - Steady state analysis
    In a steady state analysis, the thermal solver solves the temperatures of non-sink elements iteratively using the following algorithm.
  - Transient analysis
    Transient analysis is performed using the following algorithm.
  - Hydraulic network analysis
    When the hydraulic pressure-flow network is present in the model, the thermal solver solves it at each iteration or time step using the following algorithm.
  - Miscellaneous topics
  - Thermal solver theory bibliography
    The following bibliography lists all sources used to explain how the thermal solver works.
- Thermal solver API
  Allows you to create or add functionality to enhance the thermal solver capabilities.
- Thermal solver error message list
  Lists solver messages that the thermal solver generates to communicate issues with the model or the solve.

Comparison of solar radiation calculation methods

This table compares two solar flux calculation methods in thermal simulations: one based on atmospheric extinction coefficients, and another based on altitude and turbidity.


Attribute	Using atmospheric extinction coefficient	Using altitude and turbidity
Model basis	Empirical formula using extinction coefficient and the solar altitude angle	Physics-based model using altitude, Linke turbidity, and Rayleigh scattering
Atmospheric effects	Adjustment using empirical clearness factor	Detailed turbidity modeling using Linke factor and Rayleigh optical thickness
Altitude correction	Not included	Included via air pressure adjustment and modified air mass
Use cases	When atmospheric clarity and solar position vary significantly over time or location. When shadowing effects are either negligible or can be approximated separately.	For high-altitude locations, areas with variable atmospheric clarity (turbidity), or under cloudy conditions. When shadowing effects are significant.