Research On Calculation Method And Optimum Design Of Sprinkler System

Recently,the land using is in shortage,and the resource of land is kind of short-handed.The public buildings tend to be higner.Although the high-rise buildings can increase the using-efficiency of land,it also bring more risk to the public safety,especially the fire.Considering the importance grade of the building and the particularity of the corresponding place,it is difficult to put out the fire,so the automatic sprinkler system is generally installed in the building.Code for design of sprinkler systems(GB 50084-2017)stipulates that the design flow of the system should be determined by the total of the sprinkler within the working area at the most unfavorable point when they are spraying simultaneously.Hydraulic calculation of pipe network can be computed by the characteristic coefficient method when the system is arranged symmetrically.Most sprinkler systems in practical projects are asymmetrically arranged,which makes the aforementioned method only applicable for the most unfavorable branch pipe.For solving this problem,a formula named precise calculation method,which can be used to compute flow of the sprinkler in the other branch pipe when system is arranged asymmetrically,is derived by analyzing the hydraulic characteristics of the sprinkler system.The formula should be used with the assistance of progressive approximation method.Besides,the outflow of the other branch pipe in non-computational pipeline can be assumed as a hypothesis sprinkler.Introducing the parameters “k” and “n”to derives the relationship between outflow and water pressure at the end of the branch pipe,based on which a simplified calculation method is proposed.Through comparing and analyzing the results of the two methods,the feasibility of simplified calculation method can be verified.This paper also does some reasurch on the simplified calculation method.Taking the minimum engineering cost as the objective function and the pipe diameter as the decision variable to establish the optimization model and explore the optimal combination way.The influence of economic velocity and working pressure on system cost will be studied by changing the economic velocity,working pressure and other hydraulic conditions.by analysising the example.Keep the working pressure at the most unfavorable point constant and change the diameter of the pipe to control the economic velocity of the pipeline,it can be concluded that the bigger the velocity is,the higher the pipeline cost is,and the higher the total system cost is.Different economic velocitycan be optimized for different pipe diameters,but the actual operation is complicated.Keep the maximum diameter combination fixed and change the working pressure at the most unfavorable point,it can be concluded that the bigger the working pressure at the most unfavorable point is,the higher the pipeline cost is,and the higher the total system cost is.The central layout sprinkler system is superior to the side layout in cost.