Numerical investigation of kerosene single droplet ignition at high-altitude relight conditions

Giusti, Andrea; Sitte, Michael Philip; Borghesi, Giulio; Mastorakos, Epaminondas

doi:10.1016/j.fuel.2018.02.102

Cited by 23 publications

(5 citation statements)

References 23 publications

(39 reference statements)

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“…Large droplet sizes and low temperatures make the evaporation process very slow, limiting the availability of fuel vapor. 3 Therefore, much more energy is expected from the spark to ensure sufficient evaporation to have locally an ignitable fuel-air mixture, as well as to produce a flame kernel of relatively large size and increase the local temperature of the flow, leading to the kernel's successful establishment and subsequent propagation. 4 Thermal runaway is an additional peculiarity of the high-altitude ignition scenario.…”

Section: Introductionmentioning

confidence: 99%

Low-order modeling of high-altitude relight of jet engine combustors

Oliveira

Sitte

Zedda

et al. 2021

International Journal of Spray and Combustion Dynamics

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A physics-based, low-order ignition model is used to assess the ignition performance of a kerosene-fueled gas-turbine combustor under high-altitude relight conditions. The ignition model used in this study is based on the motion of virtual flame particles and their extinction according to a Karlovitz number criterion, and a stochastic procedure is used to account for the effects of spray polydispersity on the flame’s extinction behavior. The effects of large droplets arising from poor fuel atomization at sub-idle conditions are then investigated in the context of the model parameters and the combustor’s ignition behavior. For that, a Reynolds-averaged Navier-Stokes simulation of the cold flow in the combustor was performed and used as an input for the ignition model. Ignition was possible with a Sauter mean diameter (SMD) of 50 μm, and was enhanced by increasing the spark volume. Although doubling the spark volume at larger SMDs (75 and 100 μm) resulted in the suppression of short-mode failure events, ignition was not achieved due to a reduction of the effective flammable volume in the combustor. Overall, a lower ignition probability is obtained when using the stochastic procedure for the spray, which is to be expected due to the additional detrimental effects associated with poor spray atomisation and high polydispersity.

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Section: Introductionmentioning

confidence: 99%

Low-order modeling of high-altitude relight of jet engine combustors

Oliveira

Sitte

Zedda

et al. 2021

International Journal of Spray and Combustion Dynamics

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“…The results indicate that the droplets with lower evaporation mix with air and burn with a type of blue visible flame characteristics in lower pressures. Giusti et al 13 studied the ignition of a kerosene single droplet in high-altitude relight conditions using numerical simulations. The results indicate that the ignition occurs when the scalar dissipation rate decreases enough to allow the initiation of a flame kernel.…”

Section: Introductionmentioning

confidence: 99%

“…Giusti et al. 13 studied the ignition of a kerosene single droplet in high-altitude relight conditions using numerical simulations. The results indicate that the ignition occurs when the scalar dissipation rate decreases enough to allow the initiation of a flame kernel.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on spark ignition of linear combustor at low pressure conditions

Wang

Liu

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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In order to explore the influence of low pressure on ignition process, the ignition performance of a linear combustor with five burners was experimentally investigated at ambient temperature and low pressure. At air pressure drops of 1%, 2% and 3%, the influence of low pressure on the lower boundary of the ignition equivalence ratio and ignition delay have been carried, and the high-speed camera was used to record the flame propagation at various time. The results indicate that the minimum ignition equivalence ratio increases with the decrease of pressure. And, the lower the pressure, the more obvious the influence of pressure on the ignition boundary. At the same air pressure, the minimum ignition equivalent ratio decreases with the increase of the air pressure drop. For the process of ignition delay, the air pressure mainly affects the evaporation of droplets and the chemical delay process, and the air pressure drop mainly affects the physical delay stage. For the process of flame propagation, the flame moves between adjacent burners in a symmetrical pattern under various pressures. The air pressure mainly affects the ignition delay process, and the air pressure drop influences the ignition delay and the flame propagation in the early stage (the light-around from single burner to three-burners). The time needed to achieve stable combustion is the shortest at the air pressure drop of 2%.

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“…The interest in the problem of heating and evaporation of these droplets and sprays has been mainly stimulated by the importance of these processes in kerosene combustion in propulsion systems [18]. Amongst the most recent studies of these processes we mention: those presented in [19,20,21], focused on experimental studies of the evaporation characteristics of kerosene gel droplets and optimisation of kerosene ignition and combustion characteristics via addition of solid nano-particles; those presented in [22], focused on numerical studies of kerosene sprays with bio-oil additives; those in [23], focused on the numerical study of an oblique detonation wave in a two-phase kerosene-air mixture; and in [24], focused on numerical studies of the ignition of a single kerosene droplet. Although all these and similar studies have made important contributions to our understanding of the processes, most of their attention has been on the gas phase while rather simplistic models have been used for the analysis of the liquid phase.…”

Section: Introductionmentioning

confidence: 99%