A. James Clark School of Engineering

Permanent URI for this communityhttp://hdl.handle.net/1903/1654

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Browse

Filters

2007 - 200912010 - 20111

Settings

Subject: search.filters.subject.Spontaneous Ignition

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Spontaneous Ignition of Linseed Oil Soaked Cotton Using the Oven Basket and Crossing Point Methods
    (2011) Worden, Justin Thomas; Quintiere, James G; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The oven basket method coupled with the Jones version of the crossing point method was used to test the following basket sizes with their respectful concentrations of linseed oil soaked cotton, 5cm (33.3%), 5cm (50%), 5cm (75%), 7.5cm (77%), 10cm (80%) with concentrations measured by weight. Some of the samples reached three different stages; ignition, smoldering or constant smoldering and flaming. The activation energies were 42.37 kJ/mol, 27.40 kJ/mol, 16.97 kJ/mol, 15.76 kJ/mol and 11.73 kJ/mol for the 5cm (33.3%), 5cm (50%), 7.5% (77%) and 10cm (80%) basket sizes. It was concluded that as the concentration and the basket size increased the activation energy decreased. The P and M values along with the reaction rate per unit volume were also calculated. The time to ignition increased as the oven temperature that each sample was tested at decreased and as oven temperatures approached ambient the time to ignition significantly increased topping 5.5 hours for the 5cm (75%) basket size.
  • Thumbnail Image
    Item
    AN ASYMPTOTIC ANALYSIS OF SPONTANEOUS IGNITION OF HYDROGEN JETS
    (2007-04-26) lim, kianboon; Sunderland, Peter B; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Analytical work is presented for the spontaneous ignition of a hydrogen jet emanating from a slot into air. A similarity solution of the flowfield was obtained. This was combined with the species and energy conservation equations, which were solved using activation energy asymptotics. Limits of spontaneous ignition were identified as functions of slot width, flow rate, and temperatures of the hydrogen jet and ambient air. Two scenarios are examined: a cool jet flowing into a hot ambient and a hot jet flowing into a cool ambient. For both scenarios, ignition is favored with an increase of either the ambient temperature or the hydrogen supply temperature. Moreover, for the hot ambient scenario, a decrease in local fuel Lewis number also promotes ignition. The Lewis number of the oxidizer only has a weak effect on ignition. Because spontaneous ignition is very sensitive to temperature, ignition is predicted to occur near the edge of the jet if the hydrogen is cooler than the air and on the centerline if the hydrogen is hotter than the air.