Phase Change (PCM) Sample Model


The simplest concept of thermal management is that if you add energy to a material it will get hotter, and if you remove energy it will get colder. However, when matter is changing phase this is no longer true. Energy is required to alter the molecular interactions into the new phase, and this energy is called the latent heat, which is used to distinguish it from sensible heat. The energy required to change from a liquid to a solid is called the latent heat of fusion, and the energy required to change from a liquid to a gas is called the latent heat of vaporization. Reversing the phase change requires the same amount of energy but in the opposite direction.

It is easy to correctly model the energy in phase change materials with the simple table input in Thermal Desktop thermophysical properties. This sample problem was created to show how to create a phase change material and use it in a model. 

Problem Description: A transmitter is mounted on an aluminum plate. The plate is convectively cooled from the opposite side. The transmitter is normally in a stand-by state in which it only dissipates 1W. For 2 minutes every half hour, it transmits and dissipates 60W, during which time it violates its maximum allowable temperature (100°C). The mounting, boundary conditions, and power profile are fixed. The application is weight critical, but there is some available volume.

Click here to see the model in forums.

Sample Model
Thermal Systems
Material and Fluid Properties
Model Building