Effects of nozzle geometry on the reignition by hot gas jets
- 13 April 2018
- journal article
- research article
- Published by Taylor & Francis Ltd in Combustion Science and Technology
- Vol. 191 (2), 296-310
- https://doi.org/10.1080/00102202.2018.1459586
Abstract
In this paper, the ignition of a hydrogen–air mixture by a jet of burned hot gas (often termed reignition in the field of explosion protection) is studied in a two-chamber experimental configuration. This experiment allows systematic creation of hot gas jets emerging from a thin, long nozzle and them to impinge into an unburned, cold hydrogen–air mixture, possibly causing (re)ignition. In an extensive parametric study, hot exhaust gas jets originating from different nozzle diameters (0.6 mm–1.2 mm) and lengths (25 mm and 70 mm), as well as different pressure ratios along the nozzle (up to 5.5) were tested for their ability to reignite the hydrogen–air mixture. It was investigated how often reignition occurred within 10 tests under each condition. Dependencies between the occurrence of reignition and the mentioned nozzle and jet parameters were determined. It was found that the outcome (reignition or no reignition) can differ for nominally identical experimental paramete rs, which demonstrates the parametric sensitivity of the process. The statistical frequency of reignition occurrence depends on the nozzle diameter as well as on its length. For pressure ratios above the critical value, reignition occurred more often for the longer nozzle (l = 70 mm) at a given diameter. Some of these findings, notably the dependence on the nozzle length, pose a challenge to conventional models.Keywords
Funding Information
- Deutsche Forschungsgemeinschaft (TRR 150)
This publication has 17 references indexed in Scilit:
- Numerical investigation of the ignition of diethyl ether/air and propane/air mixtures by hot jetsJournal of Loss Prevention in the Process Industries, 2017
- Modelling and simulation of high-pressure hydrogen jets using notional nozzle theory and open source code OpenFOAMInternational Journal of Hydrogen Energy, 2017
- Prechamber Initiation of Gaseous Detonation in a ChannelCombustion Science and Technology, 2016
- A numerical approach to investigate the maximum permissible nozzle diameter in explosion by hot turbulent jetsJournal of Loss Prevention in the Process Industries, 2015
- Handbook of Explosion Prevention and ProtectionPublished by Wiley ,2004
- Critical dimensions of holes and slots for transmission of gas explosions: Some preliminary results for propane/air and cylindrical holesJournal of Loss Prevention in the Process Industries, 2000
- Ignition processes in hydrogenoxygen mixturesCombustion and Flame, 1988
- Structure and Velocity Measurements in Underexpanded JetsCombustion Science and Technology, 1986
- Premixed flame propagating into a narrow channel at a high speed, part 1: Flame behaviors in the channelCombustion and Flame, 1985
- Report of an Ordinary MeetingProceedings of the Institution of Mechanical Engineers, 1969