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Turbomachinery getting started
This getting started guide provides a comprehensive introduction to thermal modeling for turbomachinery applications using Simcenter 3D Thermal Multiphysics.
Introducing boundary conditions
This topic explains the different types of boundary conditions used in turbomachinery simulations and how thermal, shared, and structural conditions are applied through simulation objects, constraints, and loads to represent multiphysics behavior.
Convection boundary conditions
This topic explains what thermal boundary conditions you can use for convection.
Method 2: Coupled 1D duct fluid network
Introducing coupled 1D duct fluid network
This topic explains how to model convection using a coupled 1D duct fluid network by linking 1D flow elements to thermal surfaces.

Knowledge base articles
Knowledge base articles provide concise, practical guidance for solving thermal, flow, multiphysics, space systems, and turbomachinery modeling challenges in Simcenter 3D.
Space thermal getting started
This getting started guide provides a comprehensive introduction to space thermal modeling using Simcenter 3D Space Systems Thermal (SST).
Turbomachinery getting started
This getting started guide provides a comprehensive introduction to thermal modeling for turbomachinery applications using Simcenter 3D Thermal Multiphysics.
- Getting started with turbomachinery in Simcenter 3D
- Fundamentals of turbomachinery systems
  This topic introduces turbomachinery and explains how gas turbines convert working-fluid energy into mechanical energy or thrust. You will learn how turbomachines are classified, how the Brayton cycle describes gas turbine operation, and how the main gas turbine sections, components, and cooling systems support safe and efficient performance.
- Gas turbine design disciplines and data exchange
  This topic introduces the main engineering disciplines involved in gas turbine design and explains how they exchange data throughout the development process. You will learn how different teams collaborate, what data they produce, and how iterative workflows drive the final engine design.
- Introducing Whole Engine Model (WEM)
  This topic introduces the WEM and explains its role in gas turbine design. You will learn how WEM captures the thermal and structural behavior of the engine, what inputs it requires, and how it supports clearance and mechanical integrity assessments.
- Introducing the user interface
  This topic covers the user interface (UI) in Simcenter 3D Thermal Multiphysics. 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.
- Preparing geometry for WEM
  This topic explains why geometry preparation is critical for WEM analysis. You will learn how to simplify 3D CAD geometry into efficient 2D or hybrid models and how to prepare geometry for meshing and simulation in Simcenter 3D.
- Meshing strategy
  This topic explains how to create finite element models for WEM by combining multiple mesh types and abstraction levels.
- Managing parts and assemblies
  This topic explains how to manage parts and assemblies in WEM using associative geometry, collaborative simulation capability, and integration of submodels into a full engine simulation.
- Condition sequences
  This topic explains how condition sequences define and manage engine operating conditions over a mission cycle in WEM.
- Introducing boundary conditions
  This topic explains the different types of boundary conditions used in turbomachinery simulations and how thermal, shared, and structural conditions are applied through simulation objects, constraints, and loads to represent multiphysics behavior.
  - Thermal coupling
    This topic explains how to model heat transfer between components that are not directly connected through the mesh in WEM simulations.
  - Convection boundary conditions
    This topic explains what thermal boundary conditions you can use for convection.
    - Method 1: Surface-based convection boundary conditions
    - Method 2: Coupled 1D duct fluid network
      - Introducing coupled 1D duct fluid network
        This topic explains how to model convection using a coupled 1D duct fluid network by linking 1D flow elements to thermal surfaces.
        Define convection boundary conditions using ducts
        Learn how to model gas turbine thermal networks using a 1D duct approach.
      - Modeling the 1D duct network
        This topic explains how to model convection in a 1D duct network using two general approaches.
      - Constraining duct temperatures
        This topic explains how temperature constraints applied to duct nodes or elements influence convection coupling and temperature distribution within the thermal fluid network.
    - Comparing two methods
      This topic compares thermal streams and 1D duct networks, as well as voids and duct-node approaches, highlighting their differences in workflow, control, and suitability for modeling convective heat transfer in turbomachinery.
    - Modeling mixed flow from two ducts into the thermal stream
      This topic explains how to model mixing of flows from multiple ducts into a thermal stream, including methods using expressions, mock streams, the MIX function, and thermal stream junctions.
    - Relative temperature effects
      This topic explains how to account for total temperature effects in turbomachinery simulations, particularly in systems with rotating and stationary components.
  - Fields, expressions and plugins
    This topic explains how to define boundary condition inputs in Simcenter 3D using fields, expressions, and plugin functions. These tools allow you to model complex, time- and space-dependent behavior efficiently.
  - Radiation modeling
    This lesson explains the two Radiation simulation object types and how each defines radiative enclosures and affects radiation calculation efficiency.
  - Cyclic Symmetry
    This topic explains how to use Cyclic Symmetry in turbomachinery thermal models.
- Solving a model
  This topic explains how to configure thermal-solver settings in WEM, including convergence criteria, discretization methods, integration methods, and axisymmetric-segment control for accurate and efficient thermal analyses.
- Post-processing results
  This lesson introduces post-processing commands to help you review and evaluate simulation outcomes using visualization and data analysis.
- Mechanical integrity
  This topic explains how thermal results from WEM are mapped to detailed component models for structural and mechanical integrity analyses.
- Blade cooling
  This topic explains why blade cooling is critical in gas turbines and how advanced cooling technologies allow turbine components to operate at temperatures above material limits.
- Troubleshooting the model
  This topic explains how to verify FEM quality, material definitions, mesh integrity, and element properties before solving a thermal model.

Introducing coupled 1D duct fluid network

This topic explains how to model convection using a coupled 1D duct fluid network by linking 1D flow elements to thermal surfaces.

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

Use a coupled 1D duct fluid network to model convection by connecting 1D flow elements to thermal surfaces.


Boundary conditions	Type	Description	Output quantity	Representation
Temperature constraint (1)	Temperature	Defines source temperatures for the 1D fluid network.	Temperature
Duct Flow Boundary Condition (2)	Duct Fan/Pump	Defines mass flow for duct elements.	Mass Flow
	Duct Label	References ID for other duct flows or streams.	N/A
	Duct Total Pressure Duct Static Pressure	Applies pressure to surfaces connected to the duct.	Pressure
Thermal Coupling - Convection (3)	Convection Coupling	Couples convective surfaces to the 1D fluid network.	Heat Transfer Coefficient
Thermal Loads	Heat Generation	Defines heat generation, for example windage, in 1D elements or nodes.	Heat Generation

Setting up convective boundary conditions with Method 2

The following example shows how to setup convective boundary conditions with 1D ducts:

Blade cooling flow– Duct Flow Boundary Conditions + Convection Coupling
Disk cavity purge flow– Duct Flow Boundary Conditions + Convection Coupling
Vane cooling flow – Duct Flow Boundary Conditions + Convection Coupling
Cavity flow — Duct Node Convective Coupling
External environment — Convective Zone

Axisymmetric gas turbine cross-section showing cooling flow and applied 1D duct convective boundary conditions.

Assign each flow type to the appropriate convection boundary condition to represent the physical behavior accurately.

Hands-on material

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

Define convection boundary conditions using ducts