Consideration of Temperature Curves in Tunnel Ventilation Design

摘要

It is standard practice to design tunnel ventilation systems for normal operating conditionsrnand for emergency conditions (e.g., fire incidents). Regarding fire incidents, the adequate consideration ofrnbuoyancy effects from density changes in the vicinity of the fire is essential. Therefore, three-dimensionalrncomputational fluid dynamics calculations were prepared to improve the consideration of buoyancy effectsrnin the design of longitudinal ventilation systems. It was found that three-dimensional buoyancy effects canrnbe considered adequately in a one-dimensional approach by the use of adjusted heat transfer coefficients.rnThe latter are determined by fitting analytically calculated temperature curves downstream of the fire to thernnumerically calculated temperature curves. Equations are established to calculate the adjusted heat transferrncoefficient.