Composite Pipe Trench Cable Fire Numerical Simulation Research

With the social development, higher and higher demands on urban infrastructureconstruction is needed. According to city planning，municipal pipeline constructionbecome more comprehensive, space-efficient and beautiful.Therefore, the application ofthe utility tunnel gradually become the main way of municipal pipeline construction。When useing utility tunnel brings us convenience，it also brings the risk of fire.Once theutility tunnel breakin out of fire,it will produce a large number of flue gas that affect thework of personnel escape and cause injury or death.What`s more it will break cable linesand other municipal pipeline,cause significant economic losses.The study of utility tunnelfire simulation will made a great help of cable fire prevention and The fire service.The article analyzed the causes of cable fire from the aspects of fire risk of cablecircuits. The reasons mainly due to short circuit、overload、creepage and constrictionresistance oversize. The article individualy analyzed the theory of these reasons.Introduced cable material type,combined with practical situation of utility tunnel, selectedthe outer layer of flame retardant cable insulation materials. Useing thermal gravimetricanalyzer and cone calorimeter to take experiment and obtain the results of heat release ratemass loss rate of cable material，and observed the change of flame retardant material whenheated pyrolysis from the structural features of utility tunnel.The article Focuses on thestructure of cable trench of utility tunnel (Section design requirements,Cable arrangementdesign and fire protection system design), analyze the influence of structure on firespread;on the aspect of the software of PyroSim, analyzed the FDS numerical model，Described the theory of the use of two types of fluid dynamics model（Direct NumericalSimulation,Large Eddy Simulation) combined with Two types of combustionmodels(Timited response rate combustion model,Mixture fraction combustionmodel).Understand PyroSim works.Finally，combined with the structure of the utility tunnel,The data obtained fromthe thermodynamics experimental，and the selected cable，build a utility tunnel model tosimulate.Using the result of simulation to analyze the Smoke spread process and Heattransfer process of cable Fire of utility tunnel.And provide advice on the possession of fireprevention and fire safety measures in the analysis.