The transport and diffusion characteristics of superheated fire extinguish agent released via different nozzles in a confined space. (September 2020)

• Record Type: Journal Article
• Authors: Jiang, Yiming; Hua, Min; Yan, Peng; Zhang, Han; Li, Quanwei; Pan, Xuhai
• Is Part Of: Safety science. Volume 129(2020)
• Publication Date: 2020-09
• Subjects: Multiphase flow -- Fire extinguishing agent -- Nozzles -- Simulation; Industrial accidents -- Periodicals; Accident Prevention -- Periodicals; Safety -- Periodicals; Travail -- Accidents -- Périodiques; 363.11
• DOI: 10.1016/j.ssci.2020.104787
• Languages: English
• ISSNs: 0925-7535

Abstract

Highlights: The release of multiphase fire extinguishing agent undergoes three typical stages. The gas concentration changes at different positions of the jet are studied. The convergent nozzle has a significant impact on flow and diffusion characteristics. A simulation method for the complete release process is established. Abstract: The transport and diffusion characteristics of multiphase fire extinguishing agent released through tubes with different nozzles were studied in a confined space. In this work, the release process was characterized using pressure sensors, a gas concentration measurement system and a high speed camera. Results show that the release of fire extinguishing agent underwent three typical stages: rapid release stage, relative equilibrium stage and gas release stage. Comparisons of different nozzles showed that the convergent nozzle can slow down the pressure decay and change the discharge process in the system. Moreover, the gas concentration at different locations are related to the injector geometry of nozzle. The concentration of gas phase extinguishing agent at different sections of jets and different positions of the same section are compared. Besides, the phenomenon of atomization and dispersion became more obvious when the divergent nozzle was used, but the visibility in the confined space was low. To sum up, the convergent nozzle is suitable for fire extinguishing in a confined space. In addition, a simulation method for the complete release process is established and the results are in good correlation with the experimental data.