Study of Air Demands of Long Tunnels Based on Air-Water Two-Phase Flow Model

An air water two phase flow model for air demand computation for tunnels is developed in this paper. Based on this model,air demands of long tunnels are studied and computed for a practical project. The computation results show that the present model works well for different engineering layouts and operation conditions, as compared with the results from empirical formulation or estimation. The effects of various factors such as water flow rate, wall roughness and tunnel length on the air demand are studied. The model and conclusion drawn from this study can be used to design and construction of hydraulic tunnels.