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Multiphysics simulations

<p>Many problems in modern science or engineering are of multiphysics character. This means that they are governed by more than one type of physics, each normally represented by a set of partial differential equations. At RISE&nbsp;we can solve complex multiphysics problems to help product development or risk assessment for our customers.</p>

Heat transfer
Photo: Johan Anderson
A 2D model of the heat transferred from a heating pad into a fabric on top of a wooden board.

In order to achieve this, we have several softwares at hand such as COMSOL Multiphysics, Abaqus and OpenFOAM. The uniqueness of COMSOL Multiphysics, over other FEA software packages is its ability to solve coupled phenomena. These are phenomena for which the solution of each individual physical problem cannot be obtained independently of the others. Examples of these include combined fluid dynamics/chemical engineering or heat transfer/mechanical engineering problems.

In order to achieve high quality models, we have a database of detailed measurements of the material properties to be used in the simulations, e.g. thermal and mechanical properties, chemical species analysis and combustion behavior.

Heat transfer calculations

In many engineering applications it is of high interest to estimate the response of a product at elevated temperatures. In Abaqus and COMSOL Multiphysics the temperature in a product can be determined by using the heat transfer analysis where realistic boundary conditions are easily implemented.


CFD of a pellet bed
Photo: Johan Anderson

Coupled problem – self heating of wood pellets

An example of a coupled multiphysics problem is the self-heating in bulk storage of wood pellets solved with COMSOL Multiphysics. The wood pellets produce heat which leads to a temperature increase controlled by the heat diffusion equation. However, the amount of energy produced is controlled by the rate of chemical reactions, which is solved using Arrhenius type chemical engineering. The availability of oxygen for the reaction is controlled both by the mass diffusion laws as well as the Navier-Stokes equations of oxygen and other gases flowing in the volume. These flows are, in addition, controlled by the temperature distribution in the gas and solid state.


Structural mechanics
Photo: Johan Sjöström
Stress and deflection of a fire exposed steel beam. The simulation only shows one half of the symmetric problem.

Mechanical behavior of fire exposes beams

Full 3D simulations of fire exposed steel beams can identify weaknesses and failure times of constructions. Abaqus and COMSOL Multiphysics CAEs offers many degrees of freedom in applying boundary conditions and varying the thermal properties of materials over time, temperature or spatial coordinates.


Contact person

Johan Anderson

Forskare

+46 10 516 59 26
johan.anderson@ri.se

Read more about Johan