Gas explosion characteristics in confined straight and 90 degree bend pipes

Gas explosion inside a pipe is a complex phenomenon. Extensive studies have been carried out to investigate factors governing to the explosion development i.e. the flame speed and the maximum pressure. However, most of the works are limited to open straight pipes. Worst, the effect of the obstructio...

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Main Author:	Sulaiman, Siti Zubaidah
Format:	Thesis
Language:	English
Published:	2015
Subjects:	T Technology (General)
Online Access:	http://eprints.utm.my/id/eprint/54804/1/SitiZubaidahSulaimanPFPREE2015.pdf
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spelling	my-utm-ep.548042020-11-08T06:08:43Z Gas explosion characteristics in confined straight and 90 degree bend pipes 2015-07 Sulaiman, Siti Zubaidah T Technology (General) Gas explosion inside a pipe is a complex phenomenon. Extensive studies have been carried out to investigate factors governing to the explosion development i.e. the flame speed and the maximum pressure. However, most of the works are limited to open straight pipes. Worst, the effect of the obstructions on the explosion severity is still unclear. Most of the gases used in the industrial piping are highly combustible and has a potential to initiate detonation hazard. In this work, gas explosions inside closed pipes are considered. Experimental and Computational Fluid Dynamic (CFD) analyses using FLACs are adopted to investigate the physical and dynamic behaviour on gas explosion development in pipes. Hydrogen, acetylene, ethylene, propane and methane were used as fuels. The effect of pipe configuration (straight and 90 bend pipe) with different length to diameter ratio (L/D) was investigated. From the results, it was observed that the presence of 90 degree bend enhances the explosion severity by a factor of 1.03-3.58 as compared to that of the straight pipe. Based on the simulation analysis, the compression effect at the bending region and at the end of the pipe plays an important role to attenuate the burning rate, which resulting to a higher flame speeds and hence, increases the overpressure. Interestingly, a maximum overpressure of 14 barg with flame speed of 700 m/s was observed in the smaller pipe of L/D=40 with acetylene fuel which indicated that the detonation-like event take place. The ability of the flame to quench becomes insignificant in a smaller pipe, promoting a strong interaction of the fast flame and turbulence, particularly at the bending. This phenomenon amplifies the mass burning rate, increases the flame speeds and leading to a higher pressure rise. From the results, it shows that fuel reactivity and pipe size and configuration gives a significant effect to the overall overpressure and flame acceleration development which can lead to a catastrophic explosion. 2015-07 Thesis http://eprints.utm.my/id/eprint/54804/ http://eprints.utm.my/id/eprint/54804/1/SitiZubaidahSulaimanPFPREE2015.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:96090 phd doctoral Universiti Teknologi Malaysia, Faculty of Petroleum and Renewable Energy Engineering Faculty of Petroleum and Renewable Energy Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	T Technology (General)
spellingShingle	T Technology (General) Sulaiman, Siti Zubaidah Gas explosion characteristics in confined straight and 90 degree bend pipes
description	Gas explosion inside a pipe is a complex phenomenon. Extensive studies have been carried out to investigate factors governing to the explosion development i.e. the flame speed and the maximum pressure. However, most of the works are limited to open straight pipes. Worst, the effect of the obstructions on the explosion severity is still unclear. Most of the gases used in the industrial piping are highly combustible and has a potential to initiate detonation hazard. In this work, gas explosions inside closed pipes are considered. Experimental and Computational Fluid Dynamic (CFD) analyses using FLACs are adopted to investigate the physical and dynamic behaviour on gas explosion development in pipes. Hydrogen, acetylene, ethylene, propane and methane were used as fuels. The effect of pipe configuration (straight and 90 bend pipe) with different length to diameter ratio (L/D) was investigated. From the results, it was observed that the presence of 90 degree bend enhances the explosion severity by a factor of 1.03-3.58 as compared to that of the straight pipe. Based on the simulation analysis, the compression effect at the bending region and at the end of the pipe plays an important role to attenuate the burning rate, which resulting to a higher flame speeds and hence, increases the overpressure. Interestingly, a maximum overpressure of 14 barg with flame speed of 700 m/s was observed in the smaller pipe of L/D=40 with acetylene fuel which indicated that the detonation-like event take place. The ability of the flame to quench becomes insignificant in a smaller pipe, promoting a strong interaction of the fast flame and turbulence, particularly at the bending. This phenomenon amplifies the mass burning rate, increases the flame speeds and leading to a higher pressure rise. From the results, it shows that fuel reactivity and pipe size and configuration gives a significant effect to the overall overpressure and flame acceleration development which can lead to a catastrophic explosion.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Sulaiman, Siti Zubaidah
author_facet	Sulaiman, Siti Zubaidah
author_sort	Sulaiman, Siti Zubaidah
title	Gas explosion characteristics in confined straight and 90 degree bend pipes
title_short	Gas explosion characteristics in confined straight and 90 degree bend pipes
title_full	Gas explosion characteristics in confined straight and 90 degree bend pipes
title_fullStr	Gas explosion characteristics in confined straight and 90 degree bend pipes
title_full_unstemmed	Gas explosion characteristics in confined straight and 90 degree bend pipes
title_sort	gas explosion characteristics in confined straight and 90 degree bend pipes
granting_institution	Universiti Teknologi Malaysia, Faculty of Petroleum and Renewable Energy Engineering
granting_department	Faculty of Petroleum and Renewable Energy Engineering
publishDate	2015
url	http://eprints.utm.my/id/eprint/54804/1/SitiZubaidahSulaimanPFPREE2015.pdf
_version_	1747817730897084416

Gas explosion characteristics in confined straight and 90 degree bend pipes

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