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Furnace endoscope—measuring fuel spray properties in hot and corrosive environments

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Abstract

A furnace endoscope was developed to carry out in-furnace measurements of black liquor sprays in order to discover the initial velocity, opening angle and trajectory of the spray, and compare spray disintegration mechanisms and spray appearance with the ones measured in a spray chamber. An error analysis of the velocity measurement method was carried out, and the meaning of the optimum measurement distance from the optics to the observed object is discussed. Some details of the development process of the probe are also presented, especially the definition of the scale of the image and the cooling system of the protection tubes. The furnace endoscope can be used in difficult conditions, such as those found inside a chemical recovery boiler (~1,200°C and corrosive chemicals) with promising and accurate measurement results. The equipment has been tested in several furnaces.

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Abbreviations

d :

Distance from endoscope lens to spray surface (m)

d px :

Measured distance in a frame (pixels)

d fr :

Vertical size of the frame (pixels)

s :

Distance that the spray has moved during t (m)

t :

Time (exposure time+delay) (s)

u :

Velocity of a spray (m/s)

α :

Angle of view (°)

Δd:

Error in measuring d (m)

Δdpx:

Error in measuring dpx (pixels)

Δt:

Error in time (s)

ΔTe:

Excess temperature (°C)

ε :

Absolute error (maximum) (m/s)

ε*:

Relative error (%)

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Acknowledgements

The development work and experiments reported in this work were carried out in the research projects funded by the National Technology Agency of Finland, the Academy of Finland (project number 53606), Aker Kvaerner and the Andritz Corporation. We also thank the mill personnel for their valuable help.

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Authors and Affiliations

  1. Laboratory of Energy Engineering and Environmental Protection, Helsinki University of Technology TKK, P.O. Box 4400, 02015, TKK, Finland

    P. Miikkulainen, A. Kankkunen & M. P. Järvinen

Authors
  1. P. Miikkulainen
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  2. A. Kankkunen
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  3. M. P. Järvinen
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Correspondence to P. Miikkulainen.

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Miikkulainen, P., Kankkunen, A. & Järvinen, M.P. Furnace endoscope—measuring fuel spray properties in hot and corrosive environments. Exp Fluids 37, 910–916 (2004). https://doi.org/10.1007/s00348-004-0884-1

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  • DOI: https://doi.org/10.1007/s00348-004-0884-1

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