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Investigations of flame front propagation between interconnected process vessels: Development of a new flame front propagation time prediction model.
journal contributionposted on 23.11.2009 by Markus Roser, Albrecht Vogl, Siegfried Radandt, W. Malalasekera, Robert M. Parkin
Any type of content formally published in an academic journal, usually following a peer-review process.
For the case where a dust or gas explosion can occur in a connected process vessel, it would be useful, for the purpose of designing protection measures and also for assessing the existing protection measures such as the correct placement, to have a tool to estimate the time for flame front propagation along the connecting pipe. Measurements of data from large-scale explosion tests in industrially relevant process vessels are reported. To determine the flame front propagation time, either a 1 m3 or a 4.25 m3 primary process vessel was connected via a pipe to a mechanically or pneumatically fed 9.4 m3 secondary silo. The explosion propagation started after ignition of a maize starch/air mixture in the primary vessel. No additional dust was present along the connecting pipe. Systematic investigations of the explosion data have shown a relationship between the flame front propagating time and the reduced explosion over-pressure of the primary explosion vessel for both vessel volumes. Furthermore, it was possible to validate this theory by using explosion data from previous investigations. Using the data, a flame front propagation time prediction model was developed which is applicable for: —gas and dust explosions up to a K value of 100 and 200 bar m s-1, respectively, and a maximum reduced explosion over-pressure of up to 7 bar; —explosion vessel volumes of 0.5, 1, 4.25 and 9.4 m3, independent of whether they are closed or vented; —connecting pipes of pneumatic systems with diameters of 100–200 mm and an air velocity up to 30 m s-1; —open ended pipes and pipes of interconnected vessels with a diameter equal to or greater than 100 mm; —lengths of connecting pipe of at least 2.5–7 m.
- Mechanical, Electrical and Manufacturing Engineering