CFD analysis of jet fan layout optimization at intersection of branch tunnel and main tunnel

Abstract

To solve the ventilation tunnel pressure in the main hole with a certain slope tunnel junction produces high concentration of dust particles and harmful gas is difficult to get rid of disadvantages, based on water diversion project in yunnan Dali II period of bench mountain tunnel no. 1, on the measurements of the tunnel, first of all to modify the ventilation parameters, secondly establish three-dimensional model, USES the fluid calculation software Fluent, Through transient simulation, the standard K - $\varepsilon$ turbulence model and SIMPLEC algorithm were used for numerical simulation of jet fan layout at different heights. Finally, the flow field, wind speed and wind pressure under two working conditions were compared and analyzed to obtain the optimal height of jet fan layout and corresponding ventilation characteristics of tunnel. The results show that the flow line of wind speed at the intersection of main tunnel and branch tunnel is stable but the vortex range of branch tunnel is large when the jet fan arrangement is low. When the layout is higher, the wind velocity streamline at the intersection of main tunnel and branch tunnel is disordered, and the vortex range of branch tunnel is smaller. The best flow diversion effect is achieved at 3.5m height of jet fan.