Study of Hydrodynamic Parameters in Sprinkler Fire Extinguishing Systems

Abstract

The actuality of constructing a mathematical model describing the change in the hydrodynamic parameters of the liquid flow in the pipeline system of a sprinkler automatic fire extinguishing installation is substantiated. In the mathematical description of fluid motion in the section of the pipeline system of an automatic fire extinguishing system, a motion equation is written in the form of an ordinary differential equation describing the change in the fluid velocity with respect to time. In the test example, the adequacy of the calculated values of the fluid velocity obtained by the proposed model with the results of the analytical solution was estimated, the most optimal integration step was chosen. The developed mathematical model is approved by an example of an axonometric scheme of a sprinkler automatic fire extinguishing installation. The results of numerical calculations of the time variation of the velocity and mass flow rate of the liquid are presented, depending on the conditions for opening the sprinkler thermal lock, taking into account the pressure change in the gyro-pneumatic tank, depending on the length of the distribution pipe sections. A numerical study is made for the effect of the change in the area of the cross-sectional area of the sprinkler irrigation system and the pressure in the hydropneumatic tank in time on the speed and mass flow of the liquid. Conclusions are given for cases where the sprinkler has a time delay before reaching the full flow cross-section, and if there is a non-constant pressure in the system.