Research On The Ventilation Wall Friction Loss Of Highway Tunnel

Ventilation is the important premise to ensure safety in the construction of tunnel, which is also to ensure the safety in the later operation.The friction loss coefficient of tunnel wall is one of the important parameters of which can react the tunnel ventilation resistance characteristic, which is also the basis of he tunnel ventilation system design, optimization and the technical management and a series of work.The determination of tunnel wall friction loss coefficient is not yet mature, people mainly use empirical formula method, field test method, etc., but each tunnel engineering environment, cross section shape and support that can be applied as well as the construction units for other factors, such as the technical level of each are not identical, which lead to have too big error of the calculation results with the actual situation, which will ultimately affect the practicability of the tunnel ventilation design, bringing troubles for the construction and later operation. Then, using the fluid software Fluent, analyze the influence of fluid flow with the wall in different crude unit height and rough unit spacing and cross section diameter. Furtherly, obtain the friction loss coefficient of the wall and find the laws. Then, use the measured method combined with actual project Mao Jingba tunnel ventilation shafts and Qinling tunnel Ⅱ to get the wall friction loss coefficient, and use three-dimensional numerical simulation to simulate analysis at the same. After that, compare the results of the two methods, and get relevant conclusions. In this paper, based on the tunnel ventilation and the basic theory of fluid mechanics, simulate the tunnel under the different cross section shape, the tunnel under different size of cross section area to acquire the wall friction loss coefficient by the fluid dynamics software Fluent, and find rules or relevancies.In this paper, through the above analysis, make sure the tunnel wall friction loss coefficient more refined and more accuracy, which provide the reference for the tunnel ventilation system design calculation and the airflow distribution of the ventilation system.