Products > Discipline: Thermal Analysis > Library: THERMAL
THERMAL LIBRARY
Features
The THERMAL library, supplied with the professional version of EcosimPro, contains components to predict temperature distributions and heat flows in systems and devices using the thermal network method.
The thermal network method is also known as the lumped parameter method or the resistance/capacity method. It is essentially a finite difference method and entails modelling a continuous medium as a discrete thermal network of nodes representing the capacitance of the system linked by conductors representing its conductance.
Lumped parameter models are easily built. A thermal system with complex geometries can be replaced by a series of heat capacities and conductors (one-dimensional heat transfer) if a very detailed temperature distribution within the system is not required.
Using drag & drop methodology, the user can quickly create a diagram of the mechanical system to be analysed, the representation of which is very similar to the physical system. The capabilities of the library are vast, since customized components can be developed from the available components as a function of the modelling needs.
Thanks to EcosimPro’s features, libraries can be built that are easy to configure and extend, adding any components and characteristics as needed. This can be done graphically through a simple, user friendly interface, or through EcosimPro’s object-orientated language which makes it possible to re-use existing codes.
One of the library’s biggest advantages is the possibility of its use in the multidisciplinary facet of EcosimPro. This means that we can jointly study, for example, hydraulic systems or energy generation processes, such as combined cycle plants, and the dynamic behaviour of heat transfer through different geometrics and materials. This way, an overall study of the system is obtained with minimal design time.
Either steady-state or transient analyses can be handled with this library. The heat transfer modes that can be considered in the thermal model are conduction, radiation and natural convection. Material properties such as specific heat or conductivity may also vary with temperature.
Components
Depending on whether temperature or heat flow is calculated, most of the components of this library can be classified as:
- Capacitive components (C): they have thermal inertia, since in their formulation the temperature is calculated in the component port as a state variable: boundary thermal node, diffusive thermal node, thermal wall…
- Resistive components (R): in this case, the thermal flow, and not the temperature, is calculated as a state variable: plate divided into a number of longitudinal and transversal nodes, linear conductor, radioactive conductor
In this way, the construction of thermal networks through this library complies with the following basic rule: components having ports of the types described above (C and R) must be connected to each other in an alternating arrangement represented by the string C-R-C-R-C.
Finally, another important aspect of this library is the calculation of thermal properties based on the interpolation in external data contained in files which are provided. This enables the user to add his own files of properties. Properties for a group of materials (aluminium, carbon, carbon steel, cooper, etc) are also available.