Abstract
The ignition mechanism was studied for a group of gel fuel compositions in a high-temperature oxidizer medium. It was determined how the initial temperature of the fuel influences the ignition characteristics. The gel fuel (oil-filled cryogel) was prepared from an oil emulsion based on the mixture of a combustible liquid and polyvinyl alcohol. The composition of primary oil emulsions was as follows: the aqueous solution of polyvinyl alcohol (5, 10 wt %) + 40-60 vol % of oil + 2 vol % of emulsifier. The initial temperature of gel fuels ranged from 188 to 293 K. Combustion was initiated in high-temperature motionless air at 873-1273 K. Using a high-speed video recording system, we established that at different initial temperatures of the gel fuel, a set of identical processes occurs during the induction period; these are different from the same physical and chemical processes during the ignition of a combustible liquid. After reaching threshold conditions, the flame spreads in the droplet's vicinity from a hot spot through the gas mixture. Hot spot is an ignited and a small-sized fragment separating and moving away from the molten fuel droplet as a result of a microexplosion. The values of the main process characteristic - ignition delay times - differ 25-95% for fuel samples with the initial temperature of 293 K and temperatures of 188-233 K because of a long heating and melting stage of the latter. This is explained by a 2.5-3.6-fold difference in the amount of energy, which is necessary to supply to a colder fuel sample for this phase transformation to occur, other things being equal.
| Original language | English |
|---|---|
| Pages (from-to) | 11812-11820 |
| Number of pages | 9 |
| Journal | Energy and Fuels |
| Volume | 33 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 21 Nov 2019 |
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ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology
Cite this
Effects of the Initial Gel Fuel Temperature on the Ignition Mechanism and Characteristics of Oil-Filled Cryogel Droplets in the High-Temperature Oxidizer Medium. / Glushkov, Dmitrii O.; Nigay, Alexander G.; Yanovsky, Vyacheslav A.; Yashutina, Olga S.
In: Energy and Fuels, Vol. 33, No. 11, 21.11.2019, p. 11812-11820.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of the Initial Gel Fuel Temperature on the Ignition Mechanism and Characteristics of Oil-Filled Cryogel Droplets in the High-Temperature Oxidizer Medium
AU - Glushkov, Dmitrii O.
AU - Nigay, Alexander G.
AU - Yanovsky, Vyacheslav A.
AU - Yashutina, Olga S.
PY - 2019/11/21
Y1 - 2019/11/21
N2 - The ignition mechanism was studied for a group of gel fuel compositions in a high-temperature oxidizer medium. It was determined how the initial temperature of the fuel influences the ignition characteristics. The gel fuel (oil-filled cryogel) was prepared from an oil emulsion based on the mixture of a combustible liquid and polyvinyl alcohol. The composition of primary oil emulsions was as follows: the aqueous solution of polyvinyl alcohol (5, 10 wt %) + 40-60 vol % of oil + 2 vol % of emulsifier. The initial temperature of gel fuels ranged from 188 to 293 K. Combustion was initiated in high-temperature motionless air at 873-1273 K. Using a high-speed video recording system, we established that at different initial temperatures of the gel fuel, a set of identical processes occurs during the induction period; these are different from the same physical and chemical processes during the ignition of a combustible liquid. After reaching threshold conditions, the flame spreads in the droplet's vicinity from a hot spot through the gas mixture. Hot spot is an ignited and a small-sized fragment separating and moving away from the molten fuel droplet as a result of a microexplosion. The values of the main process characteristic - ignition delay times - differ 25-95% for fuel samples with the initial temperature of 293 K and temperatures of 188-233 K because of a long heating and melting stage of the latter. This is explained by a 2.5-3.6-fold difference in the amount of energy, which is necessary to supply to a colder fuel sample for this phase transformation to occur, other things being equal.
AB - The ignition mechanism was studied for a group of gel fuel compositions in a high-temperature oxidizer medium. It was determined how the initial temperature of the fuel influences the ignition characteristics. The gel fuel (oil-filled cryogel) was prepared from an oil emulsion based on the mixture of a combustible liquid and polyvinyl alcohol. The composition of primary oil emulsions was as follows: the aqueous solution of polyvinyl alcohol (5, 10 wt %) + 40-60 vol % of oil + 2 vol % of emulsifier. The initial temperature of gel fuels ranged from 188 to 293 K. Combustion was initiated in high-temperature motionless air at 873-1273 K. Using a high-speed video recording system, we established that at different initial temperatures of the gel fuel, a set of identical processes occurs during the induction period; these are different from the same physical and chemical processes during the ignition of a combustible liquid. After reaching threshold conditions, the flame spreads in the droplet's vicinity from a hot spot through the gas mixture. Hot spot is an ignited and a small-sized fragment separating and moving away from the molten fuel droplet as a result of a microexplosion. The values of the main process characteristic - ignition delay times - differ 25-95% for fuel samples with the initial temperature of 293 K and temperatures of 188-233 K because of a long heating and melting stage of the latter. This is explained by a 2.5-3.6-fold difference in the amount of energy, which is necessary to supply to a colder fuel sample for this phase transformation to occur, other things being equal.
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U2 - 10.1021/acs.energyfuels.9b02300
DO - 10.1021/acs.energyfuels.9b02300
M3 - Article
AN - SCOPUS:85074479903
VL - 33
SP - 11812
EP - 11820
JO - Energy & Fuels
JF - Energy & Fuels
SN - 0887-0624
IS - 11
ER -