Flame range and energy output in two-phase propylene oxide/air mixtures beyond the original premixed zone

Fuel-air cloud explosions or detonations are often affected by initial ambient conditions. A two-dimensional (2D) semi-confined model was established to study the effects of the inflowing air temperature and initial temperature of the combustor on the explosion process of isopropyl nitrate (IPN)/air mixture. The results showed that at different initial temperatures (1000-3000 K), the first peak pressure (P 1 ) and second peak pressure (P 2 ) decreased with the increase in initial temperature; the maximum flame temperature (2338-3534 K) increased with the increasing initial temperature; the explosion pressure and temperature had the opposite trends with the initial temperature, indicating that the oxygen content in the combustor had a greater impact on the explosion pressure, while the initial temperature had a more significant effect on the flame temperature. Under different incoming air temperatures (1000-3000 K), the flame temperature (~2700 K) of the two-phase explosion had a small difference at the incoming temperature of � 2500 K, signifying that the airflow temperature (< 3000 K) and the oxygen content in air jointly dominated the flame temperature; the flame temperature was 3100 K at the incoming temperature of 3000 K, which was about 300 K higher than other incoming flow temperatures, indicating that the flame temperature was more sensitive to the incoming air temperature (� 3000 K). At 600 m/s airflow, the explosion parameter curves at the inflow temperatures of 300 K and 600 K were compared, and the critical inflow temperature of the explosion process was also investigated.

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“…formula [65], which is as follows:

\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {R}_{fu\bullet A}={Y}_{fu}{Y}_{{O}_{2}}{T}^{\beta }{A}_{fu}exp\left({{-E}\over{RT}}\right)\hfill\cr}}

…”

Section: Computational Model and Methodsmentioning

confidence: 99%

“…For a one-step irreversible reaction, the laminar reaction rate can be obtained using the Arrhenius formula [65], which is as follows:…”

Section: Reaction Kinetic Modelmentioning

confidence: 99%

Energy Output of High‐speed Flowing Two‐phase IPN/Air in the Combustion Chamber

Wan

Wen

Zhang

2022

Propellants Explo Pyrotec

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“…Although considerable efforts are being made to understand the kinetics of this conversion, the detailed mechanism of the epoxidation process is still unclear. , Large-scale production of PO is often considered dangerous due to a high volatility, high flammability, and wide explosion limits of PO . In this regard, it is also considered as a model and practical fuel-air explosive. − Thus, extensive experimental and numerical studies of PO/air explosion mechanisms have been carried out using simplified and detailed kinetic schemes.…”

Section: Introductionmentioning

confidence: 99%

“… 7 In this regard, it is also considered as a model and practical fuel-air explosive. 8 − 10 Thus, extensive experimental and numerical studies of PO/air explosion mechanisms have been carried out using simplified 11 and detailed 9 kinetic schemes.…”

Section: Introductionmentioning

confidence: 99%

Propylene Oxide Addition Effect on the Chemical Speciation of a Fuel-Rich Premixed n-Heptane/Toluene Flame

et al. 2022

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1,2-Propylene oxide (PO, C 3 H 6 O) is considered as a promising agent for improving fuel. In this work, the effect of PO additives on the species pool in a premixed burner-stabilized fuel-rich (ϕ = 1.6) flame fueled by n-heptane/ toluene mixture (7/3 by volume of liquids) at atmospheric pressure is studied by the flame-sampling molecular beam mass spectrometry and numerical modeling in order to get insight into the chemical aspects of the influence of oxygenates with an epoxy group on the formation of abundant intermediates (including PAH precursors) during combustion of fossil fuels. The flames with various loadings of PO in the fuel blend (from 0 to 16.3% in mole basis) are examined, and detailed kinetic mechanisms available in the literature are validated against the measurements of mole fraction profiles of reactants, major products, and many intermediate species. A higher reactivity of the fresh mixture and a reduction in the peak mole fractions of intermediates playing an important role in PAH formation (benzene, styrene, ethylbenzene, phenol, acetylene, diacetylene, etc.) are observed when PO is added. This was found to be due to simultaneously two factors: the partial replacement of "sooting" fuel (toluene, which is the main precursor of these species) with oxygenated additive, and the changes in the flame radical pool caused by PO addition. Propylene oxide additive was found to change the ratio between H, OH, O, and CH 3 toward an increase in the proportion of O and CH 3 . The detailed kinetic mechanisms considered in the work are found to overpredict the peak mole fraction of acetylene, a key species playing a crucial role in PAH growth. Its chemistry is revisited in order to provide a better prediction of C 2 H 2 and, as a result, PAHs.

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“…2.2.2 Droplet evaporation and breakup model. When the droplet temperature reached the evaporation temperature, the evaporation of the dispersed-phase droplets was initiated until the boiling temperature of the droplets was reached or the volatility of the droplet was completely consumed (Liu and Zhang, 2019).…”

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confidence: 99%

Explosion behaviors of IPN/air mixture at high temperature and high pressure

Wan

Wen²,

Zhang³

2022

HFF

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Purpose The reaction dynamics of combustible clouds at high temperatures and pressures are a common form of energy output in aerospace and explosion accidents. The cloud explosion process is often affected by the external initial conditions. This study aims to numerically study the effects of airflow velocity, initial temperature and fuel concentration on the explosion behavior of isopropyl nitrate/air mixture in a semiconstrained combustor. Design/methodology/approach The discrete-phase model was adopted to consider the interaction between the gas-phase and droplet particles. A wave model was applied to the droplet breakup. A finite rate/eddy dissipation model was used to simulate the explosion process of the fuel cloud. Findings The peak pressure and temperature growth rate both decrease with the increasing initial temperature (1,000–2,200 K) of the combustor at a lower airflow velocity. The peak pressure increases with the increase of airflow velocity (50–100 m/s), whereas the peak temperature is not sensitive to the initial high temperature. The peak pressure of the two-phase explosion decreases with concentration (200–1,500 g/m3), whereas the peak temperature first increases and then decreases as the concentration increases. Practical implications Chain explosion reactions often occur under high-temperature, high-pressure and turbulent conditions. This study aims to provide prevention and data support for a gas–liquid two-phase explosion. Originality/value Sustained turbulence is realized by continuously injecting air and liquid fuel into a semiconfined high-temperature and high-pressure combustor to obtain the reaction dynamic parameters of a two-phase explosion.

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Flame range and energy output in two-phase propylene oxide/air mixtures beyond the original premixed zone

Cited by 20 publications

References 28 publications

Energy Output of High‐speed Flowing Two‐phase IPN/Air in the Combustion Chamber

Energy Output of High‐speed Flowing Two‐phase IPN/Air in the Combustion Chamber

Propylene Oxide Addition Effect on the Chemical Speciation of a Fuel-Rich Premixed n-Heptane/Toluene Flame

Explosion behaviors of IPN/air mixture at high temperature and high pressure

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