Equipment Rack Analysis and Design Using CFD Air Flow & Thermal Modelling

Victoria is rolling out a new Smartcard based ticket system for all train, tram and bus services, statewide. All equipment is ethernet based and has to be IP-addressable, even on the remotest country station platform.

GHD provided equipment rack analysis and design using computational fluid dynamics (CFD) air flow and thermal modeling.

More than 400 locations each require the installation of power conditioning and communications equipment to support the readers and dispensers that are required to implement the system. The study carried out relates to the performance, in full sun, of the housing selected for installation at every location.

CFD is a sophisticated computationally based design and analysis technique used by GHD that enables the simulation of fluid flows, heat and mass transfer and fluid-structure interaction.

The objective of this study was to simulate and assess the internal temperature attained during operating conditions and ascertain the effectiveness of different wall and fan designs with a need to prevent internal temperatures rising above the set limit. CFD modelling was used to gain an understanding of the temperatures reached, during worst case design conditions, with and without different fan designs and single and double skin walls. A solution was found which satisfied the operating specifications of the power and electronic equipment.

All significant equipment and solar heat sources that could influence the analysis were included in the three-dimensional CFD model.  The model was used to understand heat flows around the equipment and the effect on the internal housing temperature of ambient air drawn into the housing from the fresh air intake vents. It was found that the housing design could not rely on natural ventilation but was acceptable once equipped with forced ventilation fans.