Method for calculating smoke countercurrent length of tunnel lateral key smoke exhaust fire

Abstract

The invention relates to a method for calculating the smoke countercurrent length of tunnel lateral key smoke exhaust fire. The method comprises the following specific steps: determining an influencefactor of the smoke countercurrent length L, and establishing a relational expression between the smoke countercurrent length L and the influence factor; determining a basic dimension, and establishing a dimension relational expression between the flue gas countercurrent length L and the influence factor; determining a basic physical quantity, obtaining a dimensionless item of the influence factoraccording to a pi theorem, and obtaining a dimensionless calculation formula of the flue gas countercurrent length L by deriving; obtaining numerical values of smoke countercurrent lengths L of firedisasters under different working conditions through numerical simulation, drawing a simulation result into a scatter diagram, and making influence of influence factor on the smoke countercurrent lengths L clear; and carrying out nonlinear fitting on the result, to obtain the value of each unknown coefficient in the dimensionless relational expression, and then establishing a calculation formula of the dimensionless flue gas countercurrent length L. The method has the advantages that the method is simple and suitable for different tunnels, and guidance is provided for lateral key smoke exhausttunnel fire smoke control and fire rescue.

Description

technical field [0001] The invention relates to the technical field of tunnel fire smoke control, in particular to a method for calculating the counterflow length of smoke from a tunnel side key smoke exhaust fire. Background technique [0002] In order to alleviate the pressure of urban traffic, the application of tunnels is becoming more and more extensive. As of the end of 2017, there were 16,229 highway tunnels across the country with a total length of 15.2851 million meters. The construction of tunnels has brought convenience to people's lives, and the safety of tunnels related to it has become a major concern of people, among which tunnel fires have increasingly attracted the attention of all walks of life. Due to the tight space of the tunnel, once a fire occurs, the high-temperature smoke is not easy to discharge, which not only seriously threatens the life and property safety of drivers and passengers, but also causes bad social impact. Smoke counterflow refers to ...

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Problems solved by technology

[0003] At present, most of the existing methods for calculating the backflow length of fire smoke in centralized smoke exhaust tunnels are aimed at the situation where the smoke exhaust outlet is located at the top of the tunnel. Smoke exhaust, at this time, the stress state and motion state of the smoke have changed, and there is no calculation method for the length of smoke counterflow in tunnel fires in the lateral key smoke exhaust mode at home and abroad

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