Determination of global parameters of gas-phase oxidation reactions from heat-evolution rates in a plug flow reactor

Lisochkin, Ya. A.; Poznyak, V. I.

doi:10.1007/bf02672812

Cited by 2 publications

(1 citation statement)

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“…The preexponential factor A = 10 14 s −1 (m 3 /kg) a+b −1 (3.27 × 10 15 s −1 (m 3 /Kmol) a+b −1 ), the activation energy E a = 241.5 kJ/mole, and the fuel and oxygen concentration exponents a = 0.92 and b = 0.89 are for a one-step overall reaction of n-butanol that was obtained experimentally by Lisochkin and Pnznyak [23]. These parameters; however, led to a very large reaction rate and respectively a large heat release rate compared with that for other hydrocarbons (i.e, for n-heptane A = 3.35 × 10 11 s −1 (m 3 /kmol.s) a+b −1 , E a = 153 kJ/mole and a = b = 1 [24].…”

Section: Mathematical Modelmentioning

confidence: 96%

Thermal-drag and Transition from Quasi-steady to Highly-unsteady Combustion of a Fuel Droplet in the Presence of Upstream Velocity Oscillations

Jangi

Shaw

Kobayashi

2009

Flow Turbulence Combust

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Numerical studies on the behaviors of combustion of 1-butanol fuel droplet at presence of upstream velocity oscillation are performed. Fuel droplet has an initial diameter of 1.25 mm and ambiance pressure and temperature are 0.4 MPa and 300 K, respectively. These conditions are those in which the microgravity experiments in literature conducted. In the excellent agreement with the experimental data, numerical results show a significant enhancement of the burning rate of droplet compared to what is predicted by quasi-steady film theory models. The mechanism of the enhancement of burning rate is clarified then by observation of a new mechanism that is named thermal-drag, TD. It is shown, depending on the amplitude and frequency of the upstream velocity oscillation, the flame in wake region of droplet can move toward the droplet surface by the force of vortex flow motions produced by the TD mechanism. It is verified that such movement of the flame is responsible for the enhancement of the burning rate and deviation of the response of the evaporation process form the predictions of the quasi-steady model. Frequency analysis of the burning rate reveals that at low frequency and amplitude the FFT diagram of the burning rate contains of only one main peak synchronies with the frequency of upstream velocity oscillation, which implies a quasi-steady response. However; at high frequency and amplitude the diagram includes of wide range of 98 Flow Turbulence Combust (2010) 84:97-123 frequencies beside of the main peak that readily shows deviation from the quasisteady conditions. In the latter, the study on the response of the combustion to the upstream velocity fluctuations in which the fluctuations contains of three wave numbers shows the amplification of the effects of low frequency fluctuations rather than that of damping of the effects of high frequency fluctuations on the evaporation processes.

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Section: Mathematical Modelmentioning

confidence: 96%