Benchmarking grey particle approximations against nongrey particle radiation in circulating fluidized bed combustors

Date

2017-01-01

Author

Ates, Cihan
Selçuk, Nevin
Ozen, Guzide
Külah, Görkem

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Investigation of the effect of grey/nongrey particle property models on radiative heat fluxes and source terms is performed in the dilute zone of the lignite-fired 150kW Middle East Technical University circulating fluidized bed combustor test rig. Predictive accuracy and computational economy of several grey particle models, geometric optics approximation (GOA) with average particle reflectivity (GOA2), GOA with Fresnel solution for particle reflectivity (GOA3), and Planck mean particle properties from spectral Mie solution are tested by benchmarking their predictions against spectrally banded solution of radiative transfer equation (RTE). Comparisons reveal that all grey models lead to accurate and CPU efficient radiative heat flux predictions. On the other hand, only GOA3 and Planck mean properties are in favorable agreement with the benchmark solution for both incident fluxes and source terms. These findings indicate that grey particle approximation with GOA3 is a more practical choice in solution of RTE as it eliminates the need for spectral calculations.

Subject Keywords

Discrete ordinates method, Pulverized fuel combustion, Fly-ash particles, Heat-transfer, Scattering media, Size distribution, Coal, Enclosures

URI

https://hdl.handle.net/11511/30128

Journal

NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS

DOI

https://doi.org/10.1080/10407790.2017.1309144

Collections

Graduate School of Natural and Applied Sciences, Article

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Citation Formats

C. Ates, N. Selçuk, G. Ozen, and G. Külah, “Benchmarking grey particle approximations against nongrey particle radiation in circulating fluidized bed combustors,” NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS, pp. 467–484, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/30128.