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Title: A computational study of radiation and gravity effect on temperature and soot formation in a methane air co-flow diffusion flame

Abstract

An effort has been made for a quantitative assessment of the soot formed under steady state in a methane air co flow diffusion flame by a numerical simulation at normal gravity and at lower gravity levels of 0.5 G, 0.1 G and 0.0001 G (microgravity). The peak temperature at microgravity is reduced by about 50 K than that at normal gravity level. There is an augmentation of soot formation at lower gravity levels. Peak value at microgravity multiplies by a factor of ∼7 of that at normal gravity. However, if radiation is not considered, soot formation is found to be much more.

Authors:
 [1];  [2]
  1. Department of Mechanical Engineering, Heritage Institute of Technology, Chowbaga Road, Anandapur, Kolkata-700 107, West Bengal (India)
  2. Department of Mechanical Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah – 711103, West Bengal (India)
Publication Date:
OSTI Identifier:
22608552
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1754; Journal Issue: 1; Conference: ICME 2015: 11. international conference on mechanical engineering, Dhaka (Bangladesh), 18-20 Dec 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AIR; CHARGES; COMPUTERIZED SIMULATION; DIFFUSION; FLAMES; GRAVITATION; METHANE; SOOT; STEADY-STATE CONDITIONS

Citation Formats

Bhowal, Arup Jyoti, E-mail: arupjyoti.bhowal@heritageit.edu, and Mandal, Bijan Kumar, E-mail: bkm375@yahoo.co.in. A computational study of radiation and gravity effect on temperature and soot formation in a methane air co-flow diffusion flame. United States: N. p., 2016. Web. doi:10.1063/1.4958394.
Bhowal, Arup Jyoti, E-mail: arupjyoti.bhowal@heritageit.edu, & Mandal, Bijan Kumar, E-mail: bkm375@yahoo.co.in. A computational study of radiation and gravity effect on temperature and soot formation in a methane air co-flow diffusion flame. United States. doi:10.1063/1.4958394.
Bhowal, Arup Jyoti, E-mail: arupjyoti.bhowal@heritageit.edu, and Mandal, Bijan Kumar, E-mail: bkm375@yahoo.co.in. 2016. "A computational study of radiation and gravity effect on temperature and soot formation in a methane air co-flow diffusion flame". United States. doi:10.1063/1.4958394.
@article{osti_22608552,
title = {A computational study of radiation and gravity effect on temperature and soot formation in a methane air co-flow diffusion flame},
author = {Bhowal, Arup Jyoti, E-mail: arupjyoti.bhowal@heritageit.edu and Mandal, Bijan Kumar, E-mail: bkm375@yahoo.co.in},
abstractNote = {An effort has been made for a quantitative assessment of the soot formed under steady state in a methane air co flow diffusion flame by a numerical simulation at normal gravity and at lower gravity levels of 0.5 G, 0.1 G and 0.0001 G (microgravity). The peak temperature at microgravity is reduced by about 50 K than that at normal gravity level. There is an augmentation of soot formation at lower gravity levels. Peak value at microgravity multiplies by a factor of ∼7 of that at normal gravity. However, if radiation is not considered, soot formation is found to be much more.},
doi = {10.1063/1.4958394},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1754,
place = {United States},
year = 2016,
month = 7
}
  • A detailed soot growth model in which the equations for particle production have been coupled to the flow and gaseous species conservation equations has been developed for an axisymmetric, laminar, coflow diffusion flame. Results from the model have been compared to experimental data for a confined methane-air flame. The two-dimensional system couples detailed transport and finite rate chemistry in the gas phase with the aerosol equations in the sectional representation. The formulation includes detailed treatment of the transport, inception, surface growth, oxidation, and coalescence of soot particulates. Effects of thermal radiation and particle scrubbing of gas-phase growth and oxidation speciesmore » are also included, Predictions and measurements of temperature, soot volume fractions, and selected species are compared over a range of heights and as a function of radius. Flame heights are somewhat overpredicted and local temperatures and volume fractions are underpredicted. The authors believe the inability to reproduce accurately bulk flame parameters directly inhibits the ability to predict soot volume fractions and these differences are likely a result of uncertainties in the experimental inlet conditions. Predictions of the distributions of particle sizes indicate the existence of (relatively) low-molecular-weight species along the centerline of the burner and trace amounts of the particles that escape from the flame, unoxidized. Oxidation of particulates is dominated by reactions with hydroxyl radicals which attain levels approximately 10 times higher than calculated equilibrium levels. Gas cooling effects due to radiative low are shown to have a very significant effect on predicted soot concentrations.« less
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  • This paper reports the line-of-sight soot surface temperatures and soot volume fractions that were measured as a function of axial position in overventilated coflow laminar diffusion flames. A comparison of the influence of nitrogen dilution and the flame temperature on soot formation in diffusion flames of ethylene was made, and the relative importance of the two effects was quantified. To isolate the influence of the dilution and flame temperature, a reference condition was specified, such that the temperature of the reactants was 623 K without nitrogen dilution of the fuel gas. In dilution experiments, the temperature of reactants was atmore » the reference temperature and the nitrogen dilution of the ethylene was varied from 0 to 0.78 mole fraction. In a second set of experiments, where dilution was zero, the flame temperature was varied by reducing the temperature of the reactants from 623 to 298 K in six steps. The reduction in soot formation is due to both lowered temperature and fuel concentration in dilution experiments, and due to only lowered temperature in undiluted flames since the temperature was varied by controlling the temperature of the reactants. The difference between the two sets of results, for the same flame temperature, gives the influence of dilution on soot formation.« less
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