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Thermal radiation heat transfer and biomass combustion in a large-scale fixed bed boiler

Nilsson, Thomas LU ; Klason, Torbern LU ; Bai, Xue-Song LU and Sundén, Bengt LU (2003) 2003 ASME International Mechanical Engineering Congress In American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD 374(2). p.405-413
Abstract
The main focus of this work is to investigate the performance of some simple radiation models used in the thermal radiative heat transfer calculations in a 55 MWe fixed bed boiler with wet wood-chips as the fuel. An optically thin approach, Rosseland approximation, and the P<sub>1</sub>-approximation were utilised in the investigation. A new optimised version, as it comes to computational speed, of the exponential wide band model (EWBM) is used. The initial calculations showed that the optically thick approach failed, The optically thin approach actually gave the best prediction of the temperature, if the mean beam length (L<sub>m</sub>) was chosen carefully. The P <sub>1</sub>-approximation gave less... (More)
The main focus of this work is to investigate the performance of some simple radiation models used in the thermal radiative heat transfer calculations in a 55 MWe fixed bed boiler with wet wood-chips as the fuel. An optically thin approach, Rosseland approximation, and the P<sub>1</sub>-approximation were utilised in the investigation. A new optimised version, as it comes to computational speed, of the exponential wide band model (EWBM) is used. The initial calculations showed that the optically thick approach failed, The optically thin approach actually gave the best prediction of the temperature, if the mean beam length (L<sub>m</sub>) was chosen carefully. The P <sub>1</sub>-approximation gave less good predictions than the best optical thin case, but it could be the best engineering model to use if little was known about the mean beam length. The conclusion is that the optically thin model is sensitive to the chosen mean beam length (L<sub>m</sub>) used in the EWBM. The P<sub>1</sub>-approximation is almost insensitive to the choice of L <sub>m</sub>, due to the consideration of radiation self-absorption, where the different predicted values of the incident radiation compensate for different values of L<sub>m</sub>. For the same reason, the use of other solution techniques, such as DOM or DTM, may lead to the same conclusion, i.e., the insensitivity of the choice of L<sub>m</sub>. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Fixed bed boilers, Global warming potential (GWP)
in
American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD
volume
374
issue
2
pages
405 - 413
publisher
American Society Of Mechanical Engineers (ASME)
conference name
2003 ASME International Mechanical Engineering Congress
external identifiers
  • other:CODEN: ASMHD8
  • scopus:1842429944
ISSN
0272-5673
language
English
LU publication?
yes
id
ae8efc27-0a9d-43de-97d0-ff68378e47f2 (old id 611926)
date added to LUP
2007-11-30 15:30:23
date last changed
2018-01-07 09:37:18
@inproceedings{ae8efc27-0a9d-43de-97d0-ff68378e47f2,
  abstract     = {The main focus of this work is to investigate the performance of some simple radiation models used in the thermal radiative heat transfer calculations in a 55 MWe fixed bed boiler with wet wood-chips as the fuel. An optically thin approach, Rosseland approximation, and the P&lt;sub&gt;1&lt;/sub&gt;-approximation were utilised in the investigation. A new optimised version, as it comes to computational speed, of the exponential wide band model (EWBM) is used. The initial calculations showed that the optically thick approach failed, The optically thin approach actually gave the best prediction of the temperature, if the mean beam length (L&lt;sub&gt;m&lt;/sub&gt;) was chosen carefully. The P &lt;sub&gt;1&lt;/sub&gt;-approximation gave less good predictions than the best optical thin case, but it could be the best engineering model to use if little was known about the mean beam length. The conclusion is that the optically thin model is sensitive to the chosen mean beam length (L&lt;sub&gt;m&lt;/sub&gt;) used in the EWBM. The P&lt;sub&gt;1&lt;/sub&gt;-approximation is almost insensitive to the choice of L &lt;sub&gt;m&lt;/sub&gt;, due to the consideration of radiation self-absorption, where the different predicted values of the incident radiation compensate for different values of L&lt;sub&gt;m&lt;/sub&gt;. For the same reason, the use of other solution techniques, such as DOM or DTM, may lead to the same conclusion, i.e., the insensitivity of the choice of L&lt;sub&gt;m&lt;/sub&gt;.},
  author       = {Nilsson, Thomas and Klason, Torbern and Bai, Xue-Song and Sundén, Bengt},
  booktitle    = {American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD},
  issn         = {0272-5673},
  keyword      = {Fixed bed boilers,Global warming potential (GWP)},
  language     = {eng},
  number       = {2},
  pages        = {405--413},
  publisher    = {American Society Of Mechanical Engineers (ASME)},
  title        = {Thermal radiation heat transfer and biomass combustion in a large-scale fixed bed boiler},
  volume       = {374},
  year         = {2003},
}