Calculation method for pressure loss along pipeline of Heptafluoropropane gas fire extinguishing system
                                                            CHEN Jian, LI Xin, HU Jun kang, WANG Jian yong
（Key Lab of Special Purpose Equipment and Advanced Manufacturing Technology, Ministry of Education/Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, China）

Abstract: Aiming at calculating the pressure loss along pipeline during the process of pipe network design of Heptafluoropropane gas fire extinguishing system, a calculation method of pressure loss along pipeline of heptafluoropropane gas fire extinguishing system based on correction coefficient was proposed. The calculation formula for pressure loss along pipeline of fire extinguishing system was deduced by combining heat transfer with Bernoulli equation.According to the relationship between the pipe network parameters and its designing flow, the corresponding minimum Reynolds number was calculated, and the coefficient of pressure loss along pipeline was determined according to the value of Reynolds number. Further, the calculation formula of pressure loss along pipeline was modified, and the correction coefficient was solved by using CFD. Finally, the pressure loss calculation formula was tested through an experiment of heptafluoropropane gas fire extinguishing system. The results indicate that the calculation method for pipe network pressure loss of heptafluoropropane gas fire extinguishing system accurate and feasible.

Key words: Heptafluoropropane; pipe network design; pressure loss along pipeline; correction coefficient; CFD