Author: Elizabeth Katherine Flatbush
Publisher:
ISBN:
Category :
Languages : en
Pages : 118

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Book Description

Author: Karola Sommer
Publisher:
ISBN:
Category :
Languages : en
Pages : 40

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Book Description

Author: Narugopal Ghata
Publisher:
ISBN: 9781321608601
Category :
Languages : en
Pages :

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Book Description
A detailed computational study of evaporation and combustion phenomena of unsupported and fiber-supported single and multi-component droplets is presented. The current study consists of a total of five parts: (a) study the effects of support fibers on the vaporization of single component n-heptane droplets, (b) study the effects of the Marangoni stress in single component n-heptane droplet combustion, (c) study the effects of support fibers in single component n-heptane droplet combustion, (d) study soot shell formation for single component n-heptane droplet, and (e) study multi-component n-heptane/n-hexadecane droplet evaporation and combustion. The volume-of-fluid (VOF) method is employed in the studies to capture the liquid-gas interface for transient two-phase multidimensional flows. The calculations also include variable thermo-physical properties of the liquid and gas phases as well as Marangoni stresses. In the first part of the study, a detailed numerical investigation of the effects of support fibers on the vaporization of a fiber-supported n-heptane droplet in reduced gravity is presented. This part of the study also investigated the effects of the thickness of fiber, ambient pressure, and ambient temperature on droplet evaporation. The computational results were validated with experimental results. In the second part of the droplet combustion study, a detailed numerical investigation of the Marangoni effects for fiber supported n-heptane droplet combustion in reduced gravity is presented. A 21-step n-heptane reaction mechanism proposed by Machrafi et al. (2009) is incorporated to model the combustion with both low and high temperature chemistry. Predicted burning rates and flame diameters have been validated with data from drop tower experiments. The present computational results agree well with the experimental results. The primary focus in the third part of the study is on the effects of support fibers on the droplet burning rates and flame structure. A 21-step n-heptane reaction mechanism consisting of 20 species proposed by Zhang et al. (2013) is employed to model the combustion chemistry. Computed burning rates and flame stand-off ratios are compared with the experimental results of Jackson and Avedisian (1993). Predicted flame structures are also validated with the experimental results of Mikami et al. (1994). The present computational results agree well with the experimental results. The results indicate that the support fibers can have significant impact on droplet burning rates and flame structures. In the fourth part of the study, a detailed numerical investigation of unsupported and fiber supported n-heptane droplet combustion in reduced gravity is done to explore some important information i.e., the location of pyrolysis and soot shell using a complex multidimensional computational fluid dynamic (CFD) analysis with a detailed reaction mechanism. A 25-step n-heptane mechanism consisting of 21 species is incorporated to model the combustion. The reaction mechanism is validated for the ignition delay time. Computed burning rates and flame stand-off ratios for both unsupported and fiber-supported droplets have been validated with prior computational and experimental studies. The computed soot shell stand-off ratios are validated by comparisons with experimental and computational results. The present computational results agree well with the experimental results.In the fifth and final part, a numerical study of vaporization and combustion of unsupported and fiber-supported multi-component n-heptane/n-hexadecane droplet is presented.

Author: Anthony John Marchese
Publisher:
ISBN:
Category :
Languages : en
Pages : 626

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Book Description

Author: Israel Aharon
Publisher:
ISBN:
Category :
Languages : en
Pages : 1186

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Book Description

Author: Kishore K. Varanasi
Publisher:
ISBN:
Category :
Languages : en
Pages : 134

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Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 848

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Book Description

Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 840

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Book Description

Author: Albert Lee
Publisher:
ISBN:
Category :
Languages : en
Pages : 576

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Book Description

Author: Sergei S. Sazhin
Publisher: Springer Nature
ISBN: 3030997464
Category : Technology & Engineering
Languages : en
Pages : 603

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Book Description
This book acts as a guide to simple models that describe some of the complex fluid dynamics, heat/mass transfer and combustion processes in droplets and sprays. Attention is focused mainly on the use of classical hydrodynamics, and a combination of kinetic and hydrodynamic models, to analyse the heating and evaporation of mono- and multi-component droplets. The models were developed for cases when small and large numbers of components are present in droplets. Some of these models are used for the prediction of time to puffing/micro-explosion of composite water/fuel droplets — processes that are widely used in combustion devices to stimulate disintegration of relatively large droplets into smaller ones. The predictions of numerical codes based on these models are validated against experimental results where possible. In most of the models, droplets are assumed to be spherical; some preliminary results of the generalisation of these models to the case of non-spherical droplets, approximating them as spheroids, are presented.