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SST getting started
This getting started guide provides a comprehensive introduction to thermal modeling using Simcenter 3D Space Systems Thermal (SST).
Solving the model
This lesson introduces the numerical solution techniques used by the thermal solver for steady-state and transient thermal analyses.

Knowledge base articles
Knowledge base articles provide concise, practical guidance for solving thermal, flow, multiphysics, space systems, and turbomachinery modeling challenges in Simcenter 3D.
SST getting started
This getting started guide provides a comprehensive introduction to thermal modeling using Simcenter 3D Space Systems Thermal (SST).
- Getting started with Space Systems Thermal
- Introducing the user interface
  This topic covers the user interface (UI) in Simcenter 3D Space Systems Thermal. You will learn how to navigate the modeling environment and how to efficiently use the available tools, menus, and commands to build, set up, and review your models.
- Simulation process
  This topic covers the typical simulation workflow used to perform thermal analyses.
- Preparing a geometry for meshing
  This topic introduces the geometry creation and preparation workflow used in Simcenter 3D Space Systems Thermal. You will learn how to create or import geometry, modify and repair it for analysis, create associative copies for CAE workflows, and idealize the geometry prior to meshing.
- Meshing a model
  This lesson introduces the core meshing workflow in Simcenter 3D Pre/Post, including element selection, mesh creation, mesh organization, and assignment of material and physical properties.
- Advanced meshing and assemblies
  This lesson covers advanced meshing techniques, including primitives-based modeling, mesh controls, mesh quality improvements, and assembly-level meshing workflows.
- Applying boundary conditions
  This topic covers boundary conditions, which define how heat is generated, transferred, and constrained within a model.
- Defining thermal contacts
  This lesson introduces thermal couplings and explains how conduction, convection, and radiation couplings are used to model heat transfer between unconnected or simplified regions of a model.
- Solving the model
  This lesson introduces the numerical solution techniques used by the thermal solver for steady-state and transient thermal analyses.
  - Define a thermostat in a steady state solution
    Practice defining a Thermostat modeling object in a steady state solution.
  - Modify and solve a solution
    Practice modifying solution parameters and solving a communications satellite thermal analysis.
  - Thermal transient analysis of a power supply using thermostat and active heat controller
    This is an objective-based lab. Instead of being provided a list of instructions, you are simply provided a scenario and problem statement to solve. Please work to solve the scenario.
  - Troubleshoot the model
    Practice troubleshooting the model. The model has two issues: missing thermo-optical properties of some parts and an incomplete radiation request. You will identify and resolve these issues. You will also learn how to solve a thermal analysis using parallel processing and you will understand how to modify properties on selected elements and deactivate elements without modifying the FEM file.
- Post-processing results
  This lesson introduces post-processing commands to help you review and evaluate simulation outcomes using visualization and data analysis.
- Radiation modeling methods and optical properties
  This lesson explains the two Radiation simulation object types and how each defines radiative enclosures and affects radiation calculation efficiency.
- Orbital modeling
  This lesson explains how to define orbit parameters and solar and celestial body characteristics to establish spacecraft position, orientation, and environmental conditions for space thermal analysis.
- Solar and planetary heating
  This lesson introduces solar and planetary heating, covering solar flux, atmospheric and ground effects, model orientation, and radiative heating for space and near-planet thermal analysis.
- Multilayer and thermal protection system modeling
  This lesson introduces multi-layer shell modeling to efficiently represent layered thermal structures, including thermal protection systems and insulation, using 2D meshes with through-thickness heat transfer.
- Material transformation
  This lesson introduces material transformation modeling, including phase change, ablation, charring, and thermo-optical property degradation, for simulating materials exposed to intense thermal environments.
- Articulation and motion modeling
  This lesson introduces articulation and motion modeling to capture the thermal effects of moving and rotating components, including their impact on view factors, heat loads, and radiation.
- Joule heating and thermal devices
  This lesson introduces Joule heating and thermal device modeling, covering coupled thermal–electrical simulation, electrical boundary conditions, and simplified modeling of Peltier coolers and heat pipes.
- 1D hydraulic network modeling
  This lesson introduces 1D hydraulic network modeling to simulate fluid flow, pressure losses, and convective heat transfer in duct systems using efficient one-dimensional elements.
- Mapping the results to another model
  This lesson introduces temperature result mapping between models and explains how to align source and target models for accurate data transfer.
- Customizing the thermal solver
  This lesson explains how to extend the thermal solver using user-written subroutines and plugin functions to model custom thermal behavior.
- Creating ESC models from PCB Exchange
  This lesson introduces the PCB Exchange application and explains how to import, validate, and prepare ECAD models for thermal and structural analysis.
- Electronics thermal management
  This lesson introduces electronics thermal management in space systems, focusing on heat dissipation mechanisms, cooling techniques, and thermal modeling of printed circuit boards (PCBs) and electronic components.

Solving the model

This lesson introduces the numerical solution techniques used by the thermal solver for steady-state and transient thermal analyses.

This lesson may include hands-on exercises. Review the Discussion section for background information or click the button to proceed to the practical section.

Discussion

Simcenter 3D Space Systems Thermal uses a finite volume based thermal solver to compute steady-state and transient heat transfer solutions. The solver can handle linear and nonlinear thermal problems involving conduction, convection, and radiation. It generates thermal nodes from mesh elements, computes conductances based on geometry and material properties, assembles a global conductance matrix, and solves the resulting system of equations.

The thermal solver supports different numerical approaches for computing conductances, including the Element Center and Element CG methods. The Element CG method introduces boundary elements at beam ends, shell edges, and solid surfaces to improve accuracy, particularly for irregular meshes and models involving radiation or convection. This method is generally more tolerant of distorted elements and provides improved accuracy for complex thermal models.

Illustration showing element center and element CG methods and selection method in the dialog box.

Before solving a model, you must define a solution, which specifies the analysis type, boundary conditions, and solver options. Simcenter 3D supports steady-state and transient thermal solutions. Initial conditions define the starting temperature state for nonlinear iterations, and restart options allow reuse of previous solution data to improve convergence or recover from interrupted runs.

Solver behavior and convergence are controlled using Solver Parameters, including convergence criteria, iteration limits, relaxation factors, and conjugate gradient settings. These parameters are critical for ensuring solution stability and efficiency, especially for nonlinear problems involving radiation. Specialized options are also available to control radiative heat transfer calculations and improve performance for large or complex models.

Hands-on material

To gain experience with the topics discussed here, complete the following:

Further learning