Network Simulation And Experimental Study On Synergistic Ventilation And Smoke Exhaust In Complex Tunnels Using Multiple Driving Forces

In developing countries such as China,with the development of urbanization,traffic congestion is becoming more and more serious.In order to alleviate the traffic pressure,the development of underground space has become an inevitable choice.It is such an environment that promotes the emergence of complex underground tunnels.In the city's bustling streets,underground traffic tunnel is different from the previous single tunnel,but by a number of entrance and exit(three and above),multiple branches or with circular main tunnel,and the tunnel is usually connected with the garage or other facilities which cause the difficulties for the design of smoke control.In this paper,the tunnel is defined as a complex tunnel.The most representative of the complex tunnel is the Urban Traffic Link Tunnel,referred to as UTLT.Because of the structure of complex tunnel,the design of smoke prevention and control is not as simple as that of the conventional tunnel.Because it is located in the downtown area,the fire safety standard is higher than the conventional tunnel.More entrance and exit make the atmosphere flow complex.Especially in the case of fire,the reasonable control of the smoke flow path is particularly important.The main tunnel of some complex tunnel is looped,so it is more difficult to design the smoke control strategy.In the specific design process,we need to know whether the matching between the ventilation driving force reasonable,and the corresponding parameters whether meet the requirements,such as wind speed,flue gas temperature,the main component concentration value of smoke on each branch and the total pressure value of important nodes.In this paper,four kinds of research methods,such as theoretical analysis,numerical simulation,network simulation and small size experiment,are mainly used to study the multi driving force extract smoke synergistically in complex tunnel.The specific research contents and results are as follows:(1)Network analysis theory is applied to the complex tunnel ventilation,and a common network analysis program was developed to assist in the design of smoke control in complex tunnels.This general procedure simplifies the mathematical model of tunnel wall heat transfer,optimizes the mathematical model of hot pressing,and adds the mathematical model of the main pollutants.(2)Comparing the results of the network analysis program with the numerical simulation results of the full-scale tunnel model,the correctness and reliability of the network analysis program are verified.Including the buoyancy driving force,jet fan driving force and axial fan driving force,the multi-driving force with each other are verified by the conditions.(3)The network analysis program is used as a tool to analyze the several smoke schemes commonly used in typical complex tunnel UTLT,and the multi-drive co-exhaust smoke error and correct combinations are given.(4)The results show that the effect of multi-driving force synergetic ventilation is the best,and the effect of multi-drive co-smoke is proved by experiments.The experiment parameters can make up for some deficiencies in network simulation.Related experimental results parameters,can be used for engineering practice reference.