Thermal and geometrical features of jet fires

Article · January 2010with 55 Reads
Cite this publication
Abstract
Abstract: In many severe accidents involving explosions or large fires, jet fires have been the first step of a domino effect sequence: a recent historical analysis has shown that among the accidents registered in the data bases, in approximately 50% of the cases in which it was a jet fire it caused another event with severe effects. However, the knowledge of jet fires essential features –behaviour, effects– is still rather poor. In this communication, the results obtained with relatively large jet fires (with flame length up to 10 m) are discussed. The fuel was propane, and both sonic and subsonic jet exit velocities were obtained from different outlet diameters. The distribution of the temperatures of the flame main axis was measured with a set of thermocouples. The jet fires were filmed with a videocamera registering visible light (VHS) and a thermographic camera (IR). The main flame geometrical features were analyzed as a function of the jet main variables, as well as the thermal effects (thermal radiation intensity as a function of distance). Postprint (published version)

Do you want to read the rest of this article?

Request Full-text Paper PDF
This research hasn't been cited in any other publications.
  • Article
    The direct effects of a jet fire are among the least severe of the diverse fire accidents that can occur in industrial installations or in the transportation of hazardous materials. However, jet fires often affect equipment (e.g., a pipe or tank) that may subsequently fail and ultimately amplify the scale of the accident. This process, known as the domino effect, can have severe consequences in accidents that involve a jet fire. However, no studies have been carried out on its significance. A survey performed on data taken from several accidents databases has revealed the most frequent accident sequences. In 50% of the reported cases involving a jet fire, an additional event with severe effects also occurred.
  • Article
    Although jet fires are usually smaller than other fires, they may lead to a destructive chain of events that can increase the scale of an accident. Therefore, their size should be predicted for accurate risk assessment. In the literature, most of the proposals for estimating jet fire size concern small jet fires (up to 2.5 m in length) or subsonic flames. In this study, experiments on relatively large propane jet fires in still air were performed. Vertical turbulent diffusion flames up to 10 m in length, with sonic and subsonic mass flow rates, were obtained using six different orifice exit diameters. The experiments were filmed with video and thermographic cameras and the resulting visible and infrared images were used to determine flame length and lift-off distance. Expressions for estimating jet length as a function of several variables (mass flow rate, orifice exit diameter, Froude and Reynolds numbers) are also proposed. © 2008 American Institute of Chemical Engineers AIChE J, 2009