Structural Design And Performance Study Of The Three-phase Jet Fire Monitor

With the development of social economy,the number of high-rise buildings and petrochemical storage in cities has increased significantly.There are many kinds of combustible materials,high fire risk,and great potential safety hazards,which can easily threaten personal safety and cause economic losses.The three-phase jet fire monitor,realizes the function of "water system-ultra-fine dry powder-high pressure nitrogen" composite injection,which combines the advantages of long range,low temperature absorption and anti-reburning ability of the water monitor and the high efficiency of dry powder monitor fire extinguishing.,fulfilling high-performance fire extinguishing demand.The core component of the three-phase jet fire monitor is the nozzle structure.Through the structural calculation,simulation analysis and experimental research of the three-phase monitor nozzle,this paper designs a three-phase jet fire monitor nozzle structure and researches the jet performance.First of all,this paper introduces the background and significance of the research,summarizes the development and research status of three-phase jet firefighting technology and fire monitor at home and abroad,and focuses on the great advantages of three-phase jet firefighting technology and the existing technological progress.The main research contents and methods of this paper are put forward.Secondly,the structure design,strength check and structural optimization of the fire monitor nozzle.According to the relevant theoretical knowledge of fluid mechanics,the structure design and strength check of the fire monitor nozzle are carried out.Through the simulation analysis of the flow field in the nozzle structure,the exit velocity and the turbulent kinetic energy are compared,the best way to combine structure is the outlet diameter of 70 mm,the length of the rectifying section of 100 mm,and the convergence angle of 14°.Thirdly,the simulation analysis of the jet performance of the designed fire monitor structure is carried out.The two-phase flow field simulation of water jet in the waterway system is carried out.The water phase volume distribution and the velocity distribution on the axis and different sections of the calculation domain to determine the distribution law of the water jet flow field.The simulation of the flow state of the dry powder pipeline and the fire monitor outlet,the volume fraction and velocity distribution of the dry powder on different sections of the calculation domain were calculated under different inlet dry powder volume fractions,and the flow field distribution of the dry powder pipeline was determined.At the same time,the nitrogen pair at the exit of the firearm was simulated,and the effects of water jets determine reasonable operating parameters.Finally,a three-phase jet test system is designed and built according to the similarity criterion.Experimental research on the waterway system,using a high-speed camera to capture the jet flow field,and image processing it,analyzing the jet center trajectory,jet water column diameter,maximum diffusion ratio,initial segment divergence angle and other indicators to measure the jet performance of the designed three-phase jet fire monitor.At the same time,the firearm model was simulated by Fluent software under the same conditions,and the water phase volume distribution,velocity distribution and central jet trajectory distribution were analyzed.And,comparing the velocity and center jet trajectory obtained from the experiment and simulation,it can be seen that the simulation results can be used to predict the performance of the fire monitor in the error-allowing range,improve the jet research efficiency and reduce the research cost.The paper finally summarized the work,and the study of relevant technology is discussed as the future work.