Theoretical and Experimental Study on Velocity of Gas through Exhaust Inlet in Transversal Smoke Extraction System of Tunnel

Velocity through exhaust inlet depends on the geometry configuration of exhaust inlets and exhaust mode of the transversal exhaust system. For a given transversal exhaust system of tunnel, maximum value of velocity through the exhaust inlet might be several times of the minimum value. With same total exhaust rate and configuration of exhaust inlets, maximum velocity through individual exhaust inlet under unilateral exhaust mode is much bigger than that under bilateral exhaust mode. When designing a transversal exhaust system for a tunnel, velocity distribution of each exhaust inlet should be carefully considered according to the exhaust rate, position of the fans, exhaust inlets and the geometrical configuration of the smoke duct or channel.