Current Status of Droplet and Liquid Combustion

Faeth, G. M.

doi:10.1016/b978-0-08-024780-9.50013-7

Cited by 62 publications

(83 citation statements)

References 103 publications

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“…There are many excellent and authoritative reviews on the subject of drop combustion (Williams 1973;Faeth 1977;Law 1982;Buckmaster & Ludford 1982;Sirignano 1983;Williams 1985). Of particular relevance to this study is the theoretical work of Fendell, Sprankle & Dodson (1966), who considered drop combustion in the presence of a forced flow field that was entirely in the Stokes regime.…”

Section: Introductionmentioning

confidence: 99%

Thin-flame theory for the combustion of a moving liquid drop: effects due to variable density

et al. 1986

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Follow this and additional works at: http://repository.upenn.edu/meam_papers Part of the Mechanical Engineering CommonsSuggested Citation: Gogos, George S., et. al. (1986) The combustion of a moving liquid fuel drop has been investigated. The drop experiences a strong evaporation-induced radial velocity while undergoing slow translation. In view of the high evaporation velocity, the flow field is not in the Stokes regime. The combustion process is modelled by an indefinitely fast chemical reaction rate.While the flow and the transport in the continuous phase and the drop internal circulation are treated as quasisteady, the drop heat-up is regarded as a transient process. The transport equations of the continuous phase require analysis by a singular perturbation technique. The transient heat-up of the drop interior is solved by a series-truncation numerical method. The solution for the total problem is obtained by coupling the results for the continuous and dispersed phases.The enhancement in the mass burning rate and the deformation of the flame shape due to drop translation have been predicted. The initial temperature of the drop and the subsequent heating influence the temporal variations of the flamefront standoff ratio and the flame distance. The friction drag, the pressure drag and the drag due to interfacial momentum flux are individually predicted, and the total drag behaviour is discussed. The circulation inside the drop decreases with evaporation rate. A sufficiently large non-uniform evaporation velocity causes the circulation to reverse.

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Section: Introductionmentioning

confidence: 99%

Thin-flame theory for the combustion of a moving liquid drop: effects due to variable density

et al. 1986

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“…Spray combustion has been used very widely as engine energy [2]. Especially in the worldwide development of transportation, providing high performance of aircrafts and diesel engines [1]. Oil-fired furnaces also employ spray combustion [3].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, liquid spray offers a major contribution to meet the world's demand on the energy. The application of spray combustion in high energy density is prevaporizing systems like afterburner and ramjets, liquid rocket motor, gas turbine, industrial furnace and diesel engines [1]. Spray combustion has been used very widely as engine energy [2].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Droplet Formation Between Diesel Fuel, Emulsion and Pure Water

Sriwardani¹,

Basori²

2017

Proceedings of the International Conference on Technology and Vocational Teachers (ICTVT 2017)

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Abstract-Spray is widely used in the development of nanotechnology, both in the automotive and the industrial sector. The perfect mist is one of which is determined by droplet formation. Therefore, it is necessary to research the droplet formation characteristics of the fluid. Research begins by observing the trend of spray trajectories of diesel fuel with pressure variation. The effects of increased pressure produce a thick trajectory, filled with shadows. This shows that the liquid sprayed has largely been turned into a droplet. The next is observation of droplet formation characteristics. The study was conducted by observing the dripping process of a droplet from a disposable syringe with needle. Variety of fluids used diesel fuel, emulsion and pure water. Observation of the experiment The distance of the syringe, the diameter droplet that is formed and stretch from each droplet before dropping. The data analysis shows that diesel fuel has the greatest distance, the largest diameter and the longest stretch. While emulsion fuel has droplet formation with the smallest diameter droplet size and more solid so the stretch is the least, and the displacement is shorter than diesel fuel. While pure water has the shortest travel distance. This indicates that flocculation occurs due to the water phase being dispersed into the oil phase. Therefore, the composition should be considered to reduce the formation of inner phases that increase the viscosity of the emulsion.

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“…Faeth [49] states that previous studies have shown that radiation effects are relatively unimportant for droplet sizes representative for most fuel sprays. This conclusion is in accordance with the results of Tseng and Viskanta [141] and Godsave [61].…”

Section: Fuel Spraymentioning

confidence: 99%

“…This section gives a summary of the classical theory [49,87,128,136,149] that forms the basis of the evaporation models used in this work. The gas and liquid phase equations are briefly discussed here for single-component fuels.…”

Section: Droplet Evaporation Theorymentioning

confidence: 99%

On the atomization and combustion of liquid biofuels in gas turbines : towards the application of biomass-derived pyrolysis oil

Sallevelt¹

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This document was typeset using L A T E X.Cover image: Structure of a water spray produced by a pressure-swirl atomizer. SummaryThe combustion of liquid biofuels in gas turbines is an efficient way of generating heat and power from biomass. Gas turbines play a major role in the global energy supply and are suitable for a wide range of applications. However, biofuels generally have different properties compared to the conventional fossil fuels. This can lead to various problems when biofuels are directly used in existing installations.This thesis aims to provide better insights into the combustion of biomass-derived pyrolysis oil in gas turbines. Pyrolysis oil can be produced from non-edible biomass via the fast pyrolysis process. In this process, the organic matter is thermally decomposed under mild conditions (~500 • C, 1 atm) through rapid heating in an oxygenfree environment. The vapors formed in the reactor are subsequently condensed to obtain a combustible liquid as the main product. In comparison to the most common biofuels of the first generation, i.e. bioethanol and biodiesel, pyrolysis oil has advantages regarding cost and environmental benefits. From a technical point of view, however, it is a less favorable fuel due properties such as a low heating value, high water content, high acidity, high viscosity, increased surface tension and poor stability. Gas turbines therefore need to be modified before they can successfully operate on pyrolysis oil in pure form. One of the essential tasks is to develop a suitable burner for liquid fuels of such low quality. In this thesis, two research objectives have been formulated to support the development of pyrolysis oil combustion technology.The first objective is to describe the evaporation and flame characteristics of pyrolysis oil. This objective has been addressed by developing a CFD model based on the Euler-Lagrange method in ANSYS Fluent. The modeling approach was first applied to simulate the combustion of ethanol in a modified, downscaled diesel burner of the OPRA OP16 gas turbine rated at 1.9 MW e . This part of the numerical work can be regarded as a first step to validate the model against experiments and literature. Ethanol is a suitable replacement of pyrolysis oil for this purpose, since it is a singlecomponent, nonviscous, volatile and clean burning biofuel that has been studied more extensively in the past. In the next step, the model was further developed to simulate the full-scale combustion of pyrolysis oil in a burner that was recently designed by OPRA for biofuel applications. The complex composition of pyrolysis oil has been approximated by means of a surrogate fuel containing seven components: methanol, water, acetic acid, acetol, phenol, eugenol and levoglucosan. Each comv ponent is known to be present in pyrolysis oil and is used to represent a group of constituents with similar properties. The initial mass fractions of the seven components are chosen such that the surrogate fuel matches the volatility, water content, elemental composition...

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Current Status of Droplet and Liquid Combustion

Cited by 62 publications

References 103 publications

Thin-flame theory for the combustion of a moving liquid drop: effects due to variable density

Thin-flame theory for the combustion of a moving liquid drop: effects due to variable density

Characteristics of Droplet Formation Between Diesel Fuel, Emulsion and Pure Water

On the atomization and combustion of liquid biofuels in gas turbines : towards the application of biomass-derived pyrolysis oil

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