The Research Of Trifluoromethane Extinguishing Agent Pipe Flow Phase Based On CFD

Trifluoromethane(HFC-23) fire-extinguishing agent is one of the typical clean gas fireextinguishing agent which does not pollute the protected objects, does not destroy the ozonelayer, small greenhouse effect, harmless and low toxicity. So HFC-23fire-extinguishingsystem is a good substitute of halon fire-extinguishing agent. Currently, study on operatingrules of Heptafluoropropane and IG541mixture gas fire-extinguishing system is so thoroughthat national design specifications have been promulgated. However, pipe flow phase ofHFC-23cannot be fully obtained by experiment due to the special nature of HFC-23fire-extinguishing system itself and the complexity of its behavior in the pipe network. Thepipe flow phase is controversial, and then the choice of pressure loss calculation formula ofHFC-23fire-extinguishing system is affected. So the application of HFC-23extinguishingsystem was limited.In this paper, by using the advantage of CFD which able to accurately describe physicalphenomena of the fluid, and intuitively simulate the flow of fluid in the pipeline, confirm theflow phase of HFC-23fire-extinguishing agent and further confirm the pressure loss formula.A new method is provided for the study of pipe flow phase of HFC-23fire-extinguishingagent.Firstly, the HFC-23fire-extinguishing agent storage and discharge process were analyzedin thermodynamics，and initially identified storage state, pipe flow state and change rule ofHFC-23fire-extinguishing agent in theory. Secondly, data based on actual discharge andfire-extinguishing experiment was analyzed in detail, and the thought and model of sectionalstudy for pipe flow phase are proposed, and further identified different flow patterns ofHFC-23at different discharge stages. Finally, using the Fluent pre-processing software, athree-dimensional geometric model was established based on CFD and experimental pipelinesystem. After verifying the applicability of the model, a segmented simulation was made andsimulation results were summarized and analyzed in detail. Simulation results ultimatelyshow the pipe flow phase of HFC-23fire-extinguishing agent and the pressure losscalculation formula of HFC-23fire-extinguishing system. With experimental verification, thecauses of errors of formula calculation results were summarized.In this paper, the CFD simulation was used to study pipe flow phase of HFC-23extinguishing agent, and pipeline section simulation model was established. The method ishigh feasible, and simulation results are good visual, and has a strong practicability as well asmake up for the deficiency of huge actual experiment cost. So this method can provide theoretical reference and decision support for the further application of HFC-23fire-extinguishing system.