二氧化碳灭火系统管道压降计算模型研究

Study on calculation model of pipeline pressure drop for carbon dioxide fire extinguishing system

针对目前GB 50193-93《二氧化碳灭火系统设计规范》仅能计算高压(5.17 MPa)和低压(2.07 MPa)两种系统管路压降,且并不考虑管壁传热的影响,构建了二氧化碳灭火系统管道压降的一维稳态均相流动计算模型,建立不同系统压力条件下Y、Z系数计算公式,并采用VBA代码实现了不同系统压力条件下管道压降的快速计算。通过与国标计算结果和试验测量结果比较,验证了该模型的准确性。还通过模型定量分析了摩擦阻力系数、质量流量、高程差、环境温度对管道压降的影响,发现系统初始压力越低,受摩擦阻力系数、质量流量、高程差变化的影响越大,环境温度的变化对压降影响较小,基本可以忽略。

Against the problem of current GB 50193-93,Code for Design of Carbon Dioxide Fire Extinguishing System only calculate the pressure drop of high pressure(5.17 MPa)and low pressure(2.07 MPa)system pipelines,and the influence of heat transfer on the pipe wall is not considered,this paper builds a one-dimensional homogeneous flow calculation model for the pipeline pressure drop of carbon dioxide fire extinguishing system,establishes the calculation formula of Y and Z coefficients under different system pressure conditions,and VBA code was use to realize the rapid calculation of pipeline pressure drop under different system pressure conditions.The accuracy of the model was verified by comparing with the national standard calculation results and experimental measurement results.The new model was used to quantitatively analyze the effects of frictional resistance coefficient,mass flow rate,elevation difference,and ambient temperature on the pressure drop.It was found that the lower the system initial pressure,the bigger the influence of the frictional resistance coefficient,mass flow rate and elevation difference,and the change of temperature has little effect on the pressure drop and can be basically ignored.