Research On The Water Mist Firefighting System In Ship's Engine Room

Water mist firefighting system was considered a perfect system in keeping with ship use. But most of the existing water mist firefighting systems for ship use are working under high pressure, and the costs of the systems are very high. It's the just time to lower the system pressure, and save cost. And this is quite decided by the function of watermist nozzle and the design of the system.This paper analysised the mechanism, types of the system and the applicability of the watermist system, and so on. And it has also built a ship's watermist firefighting trial system in the laboratory. By carrying on a related experiment, I get a few pictures of the nozzles with different effects. With the combined method of the CAD and CFD, it has a numerical- value analysis of the inner flow field and the outside fog fields of the different atomized slices of the nozzle, it compares the emulation results with the lab result, so that to improve the design of the nozzle, and finally to enhance the function of the nozzle. The concrete work is as follows:Firstly, aiming at obtaining the pictures, it establishs a mobile water-mist-fog test-bed, and carry out an experiment on the designed nozzle. Then it analyzes the pictures, and gets the elementary decisions.Secondly, through analysising the whole inner flow field of the nozzle, it establishs the geometry model and mathematics model of the flow field. By making use of the fluid software FLUENT, it makes a calculation of the nozzle's inner fluxion appearance of water to get the flow characteristic of the inner flow field. By observing the inner flow field's distributtion diagrams of the pressure,speed,and the swift flow strength, it keeps a view of comprehension of the functions of the distributary slice, the revolve slice and the atomized slice, and puts forward some improving opinions.Thirdly, it build up a fog field models of two kinds of different atomized slice by using GAMBIT, and carrys on imitating and calculation of the two four kinds of different circumstances respectively by using FLUENT, to get the fog field result diagrams. Compared with the experiment results, combined with the imitating of the inner flow field, put forward a ameliorate scheme of atomization nozzle.Finally, it has also improved the designment of the ship's watermist firefighting trial system. On this foundation, it has put forward the sketch map of the watermist firefighting system in middle-low pressure of the engine room, and the collocation project of the fog nozzles.