Effects of release pressure on the transportation characteristics in pipeline and the diffusion behaviors in enclosure space of typical gas extinguishing agent. (May 2021)

• Record Type: Journal Article
• Authors: Jin, Jiaming; Pan, Renming; Li, Quanwei; Chen, Ruiyu
• Is Part Of: Journal of loss prevention in the process industries. Volume 70(2021)
• Publication Date: 2021-05
• Subjects: Safety hazards -- Gas extinguishing agent -- Release pressure -- Transportation -- Diffusion -- Holding time of concentration; Chemical industries -- Safety measures -- Periodicals; 660.2804
• DOI: 10.1016/j.jlp.2021.104441
• Languages: English
• ISSNs: 0950-4230

Abstract

Abstract: Reducing the release pressure of fire extinguishing systems can decrease potential safety hazards in large transport airplanes. To explore whether reducing the release pressure can achieve the release effect required by the airworthiness standards or not, the transportation characteristics in the pipeline and diffusion behaviors in the enclosure space of a typical fire extinguishing agent (Halon 1301) were investigated under five release pressures in the present study. The effects of the release pressure on the degree of superheat, injection duration, jet structure, and concentration distribution of Halon 1301 were analyzed. The results show that both of the degree of superheat and the injection duration decrease with an increase in the release pressure. The supplement of bubble expansion in the fire extinguishing agent can slow down the pressure decrease in the vessel. Both of the maximum and mean values of the pipeline differential pressure increase with an increase in release pressure. The maximum value of the jet angle decreases linearly with the increase in release pressure, and the jet deflects upward owing to the effects of buoyancy. The maximum concentration value decreases with an increase in the distance from the nozzle. The maximum concentration values in the near field from the nozzle increase with an increase in the release pressure. Under five release pressures, the concentration and holding time (duration above 6% volume concentration) of Halon 1301 on the centerline of the jet meet the requirements of airworthiness provisions. Highlights: Degree of superheat and injection duration both decrease with release pressure. Pressure supplement by bubble expansion in vessel and pipeline is illustrated. Maximum value of differential pressure in pipe increases with release pressure. The maximum value of jet angle decreases linearly with release pressure. The maximum concentration value near the nozzle increases with release pressure.