Articles techniques et présentations

Increasing demand for enhanced functionality and smaller form factor has led to significant increases in the power consumed by today’s electronic control modules. Consequently, improved thermal management of individual components and control modules is now a primary consideration to ensure continued, long term device operation. In industrial applications, multiple, individual control modules are often packaged in enclosures that group functioning modules together to provide a protective environment and the required inter-module connectivity. To minimize the propensity for continued maintenance of fans and other approaches for active cooling, thermal dissipation in these cabinets generally occurs by passive means. With the increased power density of individual modules, the need to understand and control the passive dissipation of thermal energy in an enclosed cabinet has come under increased focus.

Modules of differing functionality and power density are often packaged in small enclosures to limit the physical footprint, but this can restrict the ability to dissipate heat to the surrounding environment. Depending on the size of the enclosure and the power density of the individual modules, dissipation of heat is governed by a combination of conduction, convection and radiation; the resulting conjugate heat flow represents a challenging multiphysics problem. A fully coupled heat transfer and fluid flow analysis of heat sources in a confined cabinet has been conducted using COMSOL Multiphysics^® simulation software to identify the significance of conduction, convection and radiation in dissipating thermal energy and the impact that cabinet volume has on locally constraining fluid flow due to natural convection. The results of the analyses predict the thermal gradients existing within cabinets containing distributed heat sources and identify the relative importance of conduction, convection and radiation in dissipating thermal energy to the local environment. The influence of volumetric constraints on flow due to natural convection has also been investigated.