Thermal Stress Calculations

Besides the exchange of forces and deformations between a fluid and a structural code the transfer of temperature and heat transfer coefficients define a major field of application.

An example of the importance of thermal coupling is the transient heating of an automotive exhaust manifold due to flow of the internal hot exhaust gas stream. The internal flow was modeled in FLUENT while the structural heating simulation is done using ABAQUS. MpCCI provides the transfer of film coefficients from FLUENT to ABAQUS and passes the resulting surface temperature from ABAQUS to FLUENT. ABAQUS further calculates the thermal stress and deformation of the exhaust manifold due to heating, including- the effects of gaskets and bolted- connections-.

For more highly coupled thermo-mechanical problems, such displacements may also be passed back to FLUENT if the thermal distortion of the structure significantly changes the shape of the flow domain. In this way, MpCCI provides the user with the ability to use best-in-class analysis products for each domain separately.

Flow streamlines and manifold temperature distribution

Further applications realised so far with MpCCI at partners’ sites:

For the development of electrical components the prediction of thermal behavior is of high importance. Through ohmic drops the alternating current induces a heating of the system. Usually convection provides enough cooling. However, miniaturization enforces the providers of such components to optimize heat management in their products.

Example: In electrical systems the thermal behavior of busbar systems is of utmost interest. MpCCI was used to set up a coupling between a transient CFD solution (StarCD) and a computation in frequency domain (ANSYS). Temperature- dependent electrical resistivities of the conducting material are transported from StarCD to ANSYS. Joule heat losses are given back to StarCD as an energy source. Coupling communication is loose and on demand.

Electro-Thermal Coupling in a three-phase Cable Configuration