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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.
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.
Thermal void BC equations
A thermal void represents a region in a thermal model where a fluid such as air or another gas is enclosed and interacts thermally with surrounding solid boundaries. This condition is used to simulate enclosed air pockets or cavities in thermal systems.

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.
    - Free convection correlations
      Free or natural convection occurs when the heat is transferred between convective surfaces and a moving fluid, in which the fluid motion is not induced by an external force.
    - Across gap convection correlations
    - Forced convection correlations
    - Multiple convective boundary conditions on the same selection
      This section describes how the thermal solver calculates convective heat flow and post-processing outputs when multiple convective boundary conditions are applied on the same geometric selection.
    - Thermal stream BC equations
      The thermal solver models a one-sided thermal stream in thermal simulations using the energy balance equation.
    - Thermal void BC equations
      A thermal void represents a region in a thermal model where a fluid such as air or another gas is enclosed and interacts thermally with surrounding solid boundaries. This condition is used to simulate enclosed air pockets or cavities in thermal systems.
    - Convecting zone BC equations
      The thermal convecting zone boundary condition models a solid surface in contact with a fluid of known temperature and infinite heat capacity.
  - Radiation exchange
    Thermal radiation is a heat transfer due to electromagnetic radiation emitted by the surface of bodies due to their temperature.
  - Solar heating
  - 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.

Thermal void BC equations

A thermal void represents a region in a thermal model where a fluid such as air or another gas is enclosed and interacts thermally with surrounding solid boundaries. This condition is used to simulate enclosed air pockets or cavities in thermal systems.

In most cases, the specific heat, C_p, for the void fluid material is equal to 0, therefore the void equation is:

where:

T_void is the void temperature.
h is the heat transfer coefficient.
T_s is the solid surface temperature.
T_f is the fluid temperature inside the void.
dA is the differential surface area element.
Q_in is the internal power input to the void.

This leads to an implicit equation for the fluid temperature inside the void, T_f because both the heat transfer coefficient h and the heat input Q_in can be functions of T_f.

Heat input from streams or other voids

The void can also receive energy from:

Streams or ducts using the PWR(i) runtime function where i is the stream ID.
Other voids using the PWRV(m,i) runtime function where m is the mass flow rate from one void to another and i is the boundary condition ID of the void.

These are modeled using specific enthalpy functions:

where:

m_i is the incoming stream or duct mass flow.
T_i is the outlet temperature of the incoming stream or duct flow.
E(T) is the specific enthalpy:

where:

m_i is the specified incoming mass flow rate from void i into the current void.
E(T_i) is the specific enthalpy function for the fluid of void i.

Applications

Thermal voids are used in simulations where:

Air pockets are enclosed within insulation or mechanical assemblies.
No active cooling or heating is applied.
Heat exchange occurs only through conduction and convection with surrounding solids.