Simulation of large outdoor enclosures using model laws and similitude

In many electronics/telecommunication applications, switching/signal processing equipment is commonly placed in outdoor cabinets. The housed equipment generates heat that must dissipated while keeping the air temperature inside the cabinets within prescribed limits for optimum performance. Furthermore, the enclosure, being outdoors, receives full solar irradiation, creating an extra heat load that must be handled. In order to investigate flow and temperature distributions inside these enclosures, numerical simulations using computational fluid dynamics techniques are increasingly being using in conjunction with experimental methods. However, in many instances, the systems to be numerically investigated are very large and the amount of detail in the modeling is too large and complex for smaller computer systems. That is, for numerical simulation, the computational overhead is too costly. This paper presents work that incorporates similitude and model laws of testing of prototypes commonly used in aerospace and automobile applications to the simulation of large enclosures, in particular for outdoor enclosures. Results are presented in the use of other fluids (water, for example) for the simulation of larger air enclosures. Results show that model laws can be successfully implemented if the controlling parameters (dimensionless variables) are carefully chosen and matched. Results for the numerical simulation of the flow (no heat transfer) are presented and the thermal aspects of the air within outdoor enclosures are outlined