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An elementary model for autoignition of laminar jets.

Published on Jul 8, 2015
路 DOI :10.1098/rspa.2015.0059
Peter V. Gordon8
Estimated H-index: 8
(University of Akron),
Daniel J. Gotti1
Estimated H-index: 1
(USRA: Universities Space Research Association)
+ 3 AuthorsGregory I. Sivashinsky29
Estimated H-index: 29
(TAU: Tel Aviv University)
Abstract
In this paper, we formulate and analyse an elementary model for autoignition of cylindrical laminar jets of fuel injected into an oxidizing ambient at rest. This study is motivated by renewed interest in analysis of hydrothermal flames for which such configuration is common. As a result of our analysis, we obtain a sharp characterization of the autoignition position in terms of the principal physical and geometrical parameters of the problem.
  • References (26)
  • Citations (4)
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References26
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Last. Angel S谩nchez (Complutense University of Madrid)H-Index: 35
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#1Uday G. HegdeH-Index: 5
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Last. Michael C. Hicks (Glenn Research Center)H-Index: 8
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Abstract Observations of near-critical water jets are reported in the injection Reynolds number range of approximately 300鈥3000 to characterize their transition to turbulence. Three types of cases are described: (i) subcritical jet injected into subcritical water, (ii) supercritical jet injected into supercritical water, and (iii) supercritical jet injected into subcritical water. In each case, the working pressure was kept above the critical value to eliminate two-phase effects. For cases (i) a...
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#1Peter V. Gordon (University of Akron)H-Index: 8
#2Vitaly Moroz (Swansea University)H-Index: 15
We consider a generalization of the Gelfand problem arising in Frank-Kamenetskii theory of thermal explosion. This generalization is a natural extension of the Gelfand problem to two-phase materials, where, in contrast to the classical Gelfand problem which uses a single temperature approach, the state of the system is described by two different temperatures. We show that similar to the classical Gelfand problem the thermal explosion occurs exclusively owing to the absence of stationary temperat...
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#1D. FongH-Index: 1
#2J. K. BechtoldH-Index: 1
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#1Chad Augustine (MIT: Massachusetts Institute of Technology)H-Index: 2
#2Jefferson W. Tester (MIT: Massachusetts Institute of Technology)H-Index: 46
Abstract Investigations of hydrothermal flames were reviewed with three primary objectives: (1) to classify and describe experiments performed to date, (2) to assess the state of the art of experimental instruments and measurement techniques, and (3) to characterize current understanding and outline future research needs of hydrothermal flame processes. For this review, hydrothermal flames are defined as rapid oxidation reactions occurring in a supercritical aqueous environment at sufficient tem...
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#1Patrizia PucciH-Index: 36
#2James SerrinH-Index: 53
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ABSTRACT Tests designed to quantify the gravitational effects on thermal mixing and reactant injection in a Supercritical Water Oxidation (SCWO) reactor have recently been performed in the Zero Gravity Facility (ZGF) at NASA鈥檚 Glenn Research Center. An artificial waste stream, comprising aqueous mixtures of methanol, was pressurized to approximately 250 atm and then heated to 450掳C. After uniform temperatures in the reactor were verified, a controlled injection of air was initiated through a spe...
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#2Takashi UsuiH-Index: 2
Last. Hideo Sekino (Ebara Corporation)H-Index: 2
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Hydrothermal flames at 25 MPa supercritical water environment were investigated using a 4800 ml reaction tower, in which the sapphire windows were fitted for optical access. Down flowing hydrothermal flames were observed for oxidation of 2-propanol when the reactor was fed with inlet organic concentration higher than 2 vol% and air ratio higher than 1.8. Flame temperature, as high as 1100 掳C, was measured by means of a thermocouple and the temperature was found to be strongly influenced by air r...
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Supercritical hydrothermal combustion, a new and promising homogeneous combustion technology with a wide range of application scenarios and broad development prospects, provides creative ideas and means for the enhanced degradation of organic wastes, hydrothermal spallation drilling, thermal recovery of heavy oil, etc. This technology is elaborated upon in five parts: (1) introducing the main devices including semi-batch reactor and continuous reactor to study the hydrothermal flame in accordanc...
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#1Michael C. Hicks (Glenn Research Center)H-Index: 8
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Abstract Results on the autoignition and stabilization of ethanol hydrothermal flames in a Supercritical Water Oxidation (SCWO) reactor operating at constant pressure are reported. The flames are observed as luminous reaction zones occurring in supercritical water; i.e., water at conditions above its critical point (approximately 22鈥塎Pa and 374鈥壜癈). A co-flow injector is used to inject fuel (inner flow), comprising an aqueous solution ranging from 20%-v to 50%-v ethanol, and air (annular flow) i...
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#1Sivamohan N. Reddy (IITR: Indian Institute of Technology Roorkee)H-Index: 12
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