自动喷水灭火系统设计流量计算方法的研究

Research on Calculation Method of Design Flow of Sprinkler System

《自动喷水灭火系统设计规范》(GB 50084-2017)规定系统设计流量应按最不利点处作用面积内喷头同时喷水的总流量确定。当系统呈对称布置时,可用特性系数法进行管网水力计算。实际工程中大多数自动喷水灭火系统为非对称布置,特性系数法仅能用于最不利支管的水力计算。针对这一问题,对自动喷水灭火系统管网水力特性进行分析,推导出非对称布置时其他支管喷头流量计算公式并采用逐步逼近法精准求解。同时设其他支管的出流为一假想喷头,引入参数k、n,推导出支管出流量与末端水压的关系,并以此为基础提出简化算法。将两种方法计算结果进行对比分析,验证了简化算法的可行性。

Code for Design of Sprinkler Systems(GB 50084-2017)stipulates that the design flow of the system should be determined by the total flow of the sprinkler within the working area at the most unfavorable point when they are spraying simultaneously.The hydraulic calculation of pipe network can be carried out by the characteristic coefficient method when the system is symmetrically arranged.Most automatic sprinkler systems in practical projects are asymmetrically arranged,which makes the characteristic coefficient method only applicable for the most unfavorable branch pipe.For solving this problem,the hydraulic characteristics of the sprinkler system was analyzed,and formula named precise calculation method,which can be used to calculate flow of the sprinkler in the other branch pipe when system is arranged asymmetrically was deduced.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 derive the relationship between outflow and water pressure at the end of the branch pipe,based on which a simplified calculation method was proposed.Through comparing and analyzing the results of the two methods,the feasibility of simplified calculation method can be verified.