Numerical Study On Smoke Control And Exhaustion Of Ship's Galley Under Fire Condition

Nowadays,ship industry has achieved significant development both in military and civil fields.And people have started to pay more attention on ship safety,among all the factors concerned to ship safety,fire is most hazardous,once happened,it will cause great economic losses and casualties.In general ship design process,there always has space limitation,and designing an independent smoke exhaustion system will occupy a lot space.Thus,based on the existing air conditioning and ventilation system,through integration and optimization,taking advantage of current fan,air duct and vent for smoke exhaustion system design,will save the space and equipment costs practicably.Usually,the ship's galley has huge potential hazards,because it has open fire and many electrical appliances.Therefore,strengthen the research on smoke control and exhaustion system of ship's galley under fire condition will be very helpful to control the fire spread and reduce casualties and property losses.In this paper,the fire numerical simulation software PyroSim is used to do the related research.Firstly,through the comparison of experiment and numerical simulation,proving the accuracy of using the PyroSim software to simulate soybean oil combustion,besides,testing the sensitivity of computational mesh to select a proper mesh size on the basis of computational accuracy,reduce the mesh quantity and save the computation time.Secondly,by summarizing the existing technical specification on air conditioning,ventilation and fire protection system of ship's galley,and consulting some related technical standards for building smoke control,furthermore,combining with the structural characteristic of a 9200 TEU container vessel's galley chosen in this paper,an integration method for vent,fan and air duct of ship's galley has been proposed.Then,a theoretical verification for this plan has been carried out in many aspects,such as total smoke exhaust volume,critical smoke exhaust volume for each vent,air make-up volume,the temperature tolerance of exhaust hood and air duct.Finally,the numerical research has been implemented on the smoke control and exhaustion plan for ship's galley by PyroSim software.The impact of different exhaust hood position,air make-up position and velocity on exhaust effect has been studied,accordingly,through comprehensive analysis,the most applicable smoke control and exhaustion plan for the ship's galley of this type could be achieved.It has been found out that while using the PyroSim software to simulate soybean oil combustion,the simulation result could match the experimental result better in igniting and abating stage,despite of a little higher in the peak area,it could still meet the accuracy requirements.When designing the smoke exhaustion plan for the ship's galley of this type,the smoke exhaustion system could share some fans,vents and air ducts with air exhaustion system by using inverter.Besides,the air make-up system could share some fans and air ducts with air supply system,and the vent could be designed separately as required.When setting the exhaust hood on the corner of ceiling diagonally opposite to the door,air make-up vent on the wall facing the door,meanwhile,reducing the air make-up velocity,the smoke exhaustion system would have a perfect performance.