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Laser diagnostics of pulverized coal combustion in O2/N2 and O2/CO2 conditions: velocity and scalar field measurements


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Authors

Balusamy, S 
Kamal, MM 
Lowe, SM 
Tian, B 
Gao, Y 

Abstract

Optical diagnostic techniques are applied to a 21 kW laboratory-scale pulverized coal–methane burner to map the reaction zone during combustion, in mixtures with varying fractions of O_2, N_2 and CO_2. Simultaneous Mie scatter and OH planar laser-induced fluorescence (PLIF) measurements have been carried out to study the effect of the oxidizer/diluent concentrations as well as the coal-loading rate. The spatial distribution of soot is captured using laser-induced incandescence (LII). Additionally, velocity profiles at selected axial locations are measured using the pairwise two-dimensional laser Doppler velocimetry technique. The OH PLIF images capture the reaction zones of pilot methane–air flames and the variation of the coal flame structure under various O_2/CO_2 compositions. Coal particles devolatilize immediately upon crossing the flame interface, so that the Mie scatter signal almost vanishes. Increasing coal-loading rates leads to higher reaction rates and shorter flames. LII measurements show that soot is formed primarily in the wake of remaining coal particles in the product regions. Finally, differences in the mean and RMS velocity field are explained by the combined action of thermal expansion and the changes in particle diameter between reacting and non-reacting flows.

Description

Keywords

40 Engineering, 4017 Mechanical Engineering, 4002 Automotive Engineering

Journal Title

Experiments in Fluids

Conference Name

Journal ISSN

0723-4864
1432-1114

Volume Title

56

Publisher

Springer Science and Business Media LLC
Sponsorship
Engineering and Physical Sciences Research Council (EP/K02924X/1)
This work is supported by EPSRC research Grant (#EP/G062153/1). Yi Gao is supported by EPSRC Grant (#EP/K02924X/1), S. Lowe acknowledges support through an EPSRC DTA grant, M. Kamal is supported by University of Engineering and Technology Peshawar (Pakistan), and Bo Tian acknowledges support from CSC.
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