For transient simulations with laminar or turbulent flow. This solver uses the PIMPLE method for iterative solution.
For Steady State simulations with laminar or turbulent flow. This solver uses the SIMPLE method for iterative solution.
In order to perform a CHT simulation on a given domain you have to discretize your geometry by creating a mesh. Details of CAD handling and Meshing are described in the Pre-processing section.
For CHT analysis, CAD must meet certain necessary requirements which can be seen in the Pre-processing section.
After a mesh domain is assigned to the simulation, it is possible to use domain-related entities associated with the mesh in setting up the simulation.
Additionally, one can view the mesh or define new entities, e.g. a Topological Entity Set, to facilitate the simulation setup process. Details of each step are described in the following sections:
Under model the gravity and the thermal properties of the system (for all regions) must be defined. Moreover, if LES turbulence model is being used, the LES delta coefficient should be specified as well.
For CHT, several fluid and solid materials are available from the Material Library.
The Fluid material properties and behavior are defined by Thermal fluid model.
The user has various options to choose from which are described in detail under Thermal Fluid properties. – Thermal Fluid properties
The Solid material properties and behavior are defined by Thermal solid model.
The user has various options to choose from which are described in detail under Thermal Solid properties. – Thermal Solid properties
In a conjugate heat transfer simulation, the computational domain will be solved for pressure (p), velocity (U), temperature (T), and etc. Depending on the choice of solver, additional turbulent transport quantities may be included. The initial conditions play a vital role in the stability and computing time of the simulation. Therefore, it is very important to define appropriate initial conditions for the simulation.
It is recommended to set the initial conditions close to the expected solution to avoid potential convergence problems.
For CHT analysis type, the velocity and temperature variables could be initialized either uniformly or seperately via a ‘Subdomian’ for each region. the two methods are detailed below.
Finally, the following boundary conditions are available for each variable:
As a general practice, the boundary conditions must be specified for all surfaces, except the interfaces.
Numerical settings play an important role in simulation configuration. Ideally, they could enhance stability and robustness of the simulation. Since the optimal combination is not always trivial to find, default values are tried to be as meaningful and relevant as possible.
However, all numerical setting are made available for users to have full control over the simulation. These settings are divided into three categories:
All properties regarding the iterative solvers of velocity and pressure equations are set here. Relaxation factors, residual controls, and solver-specific tweaks are among these settings. However, depending on the solver (e.g. PIMPLE, PISO, …), these settings will be adjusted. For each field, a Help message is provided on the platform.
In this part, linear solvers used in computing each variable could be chosen separately. Upon choosing a solver, a set of preconditioners/smoothers and their tolerances become available. To assist with selecting the best solver, a Help message is provided for each field.
- Numerical Schemes
These schemes determine how each term in the governing equations should be discretized. Schemes categorized in the following groups:
- Time differentiation
- Surface-normal gradient
Generally, for Numerical Schemes the default selections are the best choice and require no changes.
The Simulation Control settings define the general controls over the simulation. Number of iterations, simulation interval, timestep size, and several other setting could be set. The following controls are available:
Result Control allows users to define extra simulation result outputs. Each result control item provides data that requires additional calculation. The following result control items are available:
Conjugate heat transfer analysis is performed using the OpenFOAM software. See our Third-party software section for further information.
This offering is not approved or endorsed by OpenCFD Limited, the producer of the OpenFOAM software and owner of the OPENFOAM® and OpenCFD® trade marks. OPENFOAM® is a registered trade mark of OpenCFD Limited, the producer of the OpenFOAM software