The Study On Distribution Law Of The Fire Detection Parameters In Confined Space Under Microgravity

As to natural convection disappear in the microgravity confined space environment,the distribution of fire detection parameters is mainly affected by forced convection.If installing fire detector use the method under normal gravity,the false alarm rate and false positive rate will inevitably increase.So,scientific and rational installing fire detector,must comprehensive and systematic to study the distribution law of the fire detection parameters.The distribution law experiment of fire detection parameters under microgravity confined space need a long time,but at present,using drop tower,shaft,weightless aircraft and other equipment can only get a few seconds microgravity environment,unable to meet the needs of long study.Then,this paper refers to the similarity theory to simulated microgravity environment under normal gravity approximately.Commonly via to maintain Re,and reduce Gr to realize function similar simulation,this method include shrink analogy method,reduced pressure method and flop out method.In this paper,based on previous achievement,proposing a new function similar simulation method that via to maintain Gr,and increase Re to realize function similar simulation.This paper use two expriments to checking its validity before use this method.The results of checking expriments indicate that variable Re function similar simulation method can be used for studying the distribution law of fire detection parameters under microgravity confined spaces in ground.Developed confined space fire ground simulation platform by variable Re function similar simulation theory.Using the platform to carry out ventilated condition affected expriments of distribution law of fire detection parameters and distribution law of fire detection parameters which fire source in different location.Due to similar simulation method can not simulate the distribution law when fire source is located in all sides,the computer numerical simulation methods used for studying distribution law when fire sounce is located in all sides.Two expriments separetelly indicate the distribution law of fire detection parameters in the microgravity confined space under weak forced convection and weak natural convection.