Investigation On Key Techniques Of Foam Fire-Fighting Simulator

China has become the largest oil import country and the largest oil consumption country in the world.Oil fire is characterised by high heat release rate,strong flowability and easy reburning.Once oil fire happens,serious consequences may arise.Foam fire-fighting is the most effective way to suppress oil fires.When the foam is used in the oil fire,the foam could float above the flammable liquild surface and cover the burning surface.That method could not only cool the flammable liquild fuel,but also isolate the contact of combustible gas and air.Many departments have carried out a lot of fire fighting trainings,such as local fire department,navy,air force and airports,where the liquid fuel is used frequently.However,the heat release rate cannot be controlled in these training methods.It also could lead to serious water and air pollution.Recently,researchers in foreign countries conducted lots of studies for fire-fighting training to replace liquid fuel by gas fuel.However,there are still lots of fundamental problems to be solved.Therefore,it is necessary to conduct scientific research to find a new method to develop new Foam Fire-fighting simulation devices.In the paper,some studies related with fire-fighting simulating apparatus were investigated,including specification requirements,technology status and industry status.Then,an alternative approach using combustible gas fuel to simulate fire scenario was introduced.In order to simulate fires correctly,there were two key scientific issues,including the simulation of fire source and the simulation of feedback during extinguishing.In order to develop the simulation device,two technical problems were proposed and solved,including the fire source simulation and the change of feedback during the fire suppression.Finally,the design for Foam Fire-fighting simulation device was presented,where the program for controlling heat release rate was given.Main fundings include:(1)The main technology principles of Foam Fire-fighting Simulator were presentedThe overall functional requirements of the Foam Fire-fighting Simulator were clarified.There were two key technology,including the simulation of fire source and the simulation of feedback during extinguishing.Some equivalent principles were proposed for the design,where the gas fuel was used to replace the liquid fuel in the simulaton of fire source,including heat release rate,flame shape and radiant flux.The fire source using gas fuel could make feedback during the extinguishing of foam fire-fighting.(2)The calculation method for the flame shape and radiant flux was introduced when using gas fuel as fire source.The burning characteristics of aviation kerosene and propane fire source were studied through experimental investigations and theoretical analyzes.The burning parameters,including flame height and radiation flux were compared and analyzed for aviation kerosene and propane fire source.The calculation method for flame height and radiation flux was proposed to replace the aviation kerosene by propane.Base on this methond,the flow rate of propane could be determined,so that the burning characteristics of gas fuel could be similar to the burning characteristics of aviation kerosene,including flame height and radiation flux.(3)The foam loss models under the conditions that with or without the flame radiation effect were derived,and the foam extinguishing feedback mechanism was modeledThe influences of foam flow rate and foam multiple on the foam spreading rate was investigated by the laboratory scale foam spreading experiments.The relevant parameters of the theoretical foam spread model were determined.The one-dimensional and the axisymmetric foam spread models were derived.The foam thickness changing process of the foam under the effect of the thermal radiation was analyzed.The quantitative relationship between the foam thickness reduction rate and radiation flux was obtained,and the calculation method of foam thickness reduction rate coupled with thermal radiation intensity was established.A foam extinguishing feedback model,which represented the effect of foam extinguishing agent was established,considering the effect of foam extinguishing agent,foam spreading and thermal radiation.Based on the model calculation,the foam extinguishing analog device can realize the comprehensive feedback control of fire source.(4)The design for Foam Fire-fighting simulation device was presented and verified by the the prototype application.The design for Foam Fire-fighting simulation devices was presented.The system composition and function were clarified.Otherwise,some detailed designs were given for some important equipments such as permanent burner,main burner,gas supply device,foam collector,foam measuring device and program controller.Based on calculation method,some control parameters were given for a typical fire scenarios,and the core program of in the program controller was compiled to control the fire source.The engineering application of Foam Fire-fighting simulation device was discussed,when using the aircraft-type foam fire extinguishing simulation device as an example.The functional requirements of the aircraft-type Foam Fire-fighting Simulator were proposed.The design of the aircraft engine fire and brake system fire was completed.A prototype of aircraft-type Foam Fire-fighting simulation device was created and applied to the application.The study fills the domestic technological gap in this field.