Compact Modeling of a Telecommunication Cabinet

Abstract

Computational Fluid Dynamics (CFD) is widely used in the telecommunication industry to validate experimental data and obtain both qualitative and quantitative results during product development. A typical outdoor telecommunications cabinet requires the modeling of a large number of components in order to perform the required air flow and thermal design. Among these components, the heat exchanger is the most critical to thermal performance. The cabinet heat exchanger and other thermal components make up a complex thermal system. This thermal system must be characterized and optimized in a short time frame to support time-to-market requirements. CFD techniques allow for completing system thermal optimization long before product test data can be available. However, the computational model of the complex thermal system leads to a large mesh count and corresponding lengthy computational times. The objective of this paper is to present an overview of techniques to minimize the computational time for complex designs such as a heat exchanger used in telecommunication cabinets. The discussion herein presents the concepts which lead to developing a compact model of the heat exchanger, reducing the mesh count and thereby the computation time, without compromising the acceptability of the results. The model can be further simplified by identifying the components significantly affecting the physics of the problem and eliminating components that will not adversely affect either the fluid mechanics or heat transfer. This will further reduce the mesh density. Compact modeling, selective meshing, and replacing sub-components with simplified equivalent models all help reduce the overall model size. The model thus developed is compared to a benchmark case without the compact model. Given that the validity of compact models is not generalized, it is expected that this methodology can address this particular class of problems in telecommunications systems. The CFD code FLOTHERM™ by Flomerics is used to carry out the analysis.