Abstract

We describe a simple technique for measuring high (up to 0.16) time-averaged solids volumetric concentration in a two-phase flow. The technique is based on a properly modified version of the forward scattering of laser light. It is useful in a variety of practical configurations, and, in particular, it is instrumental in the diagnostics of particle flow in the free board of bubbling fluidized beds and in the circulating fluidized beds. A fallout of this work is the measurement of the extinction coefficient of the solid material tested.

© 1990 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. U. Arena, A. Cammarota, L. Massimilla, D. Pirozzi, “The Hydrodynamics Behaviour of Two Circulating Fluidized Bed Units of Different Sizes,” in Circulating Fluidized Bed Technology II, P. Basu, J. F. Large, Eds. (Pergamon, London, 1988), pp. 223–230.
  2. L. Massimilla, “Behaviour of Catalytic Beds of Fine Particles at High Gas Velocities,” AIChE Symp. Ser. 69, 11–13 (1973).
  3. D. J. Holve, “In Situ Optical Particle Sizing Technique,” J. Energy 4 (4), 176–183 (1980).
    [CrossRef]
  4. E.-U. Hartge, D. Rensner, J. Werther, “Solids Concentration and Velocity Patterns in Circulating Fluidized Beds,” in Circulating Fluidized Bed Technology II, P. Basu, A. J. F. Large, Eds. (Pergamon, London, 1988), pp. 165–180.
  5. F. Beretta, A. Cavaliere, A. D’Alessio, “Drop Size and Concentration in a Spray by Sideward Laser Light Scattering Measurements,” Combust. Sci. Technol. 36, 19–37 (1984).
    [CrossRef]
  6. K. L. Cashdollar, C. K. Lee, J. M. Singer, “Three-Wavelength Light Transmission Technique to Measure Smoke Particle Size and Concentration,” Appl. Opt. 18, 1763–1769 (1979).
    [CrossRef] [PubMed]
  7. P. C. Ariessohn, S. A. Self, R. H. Eustis, “Two-Wavelength Laser Transmissometer for Measurements of the Mean Size and Concentration of Coal Ash Droplets in Combustion Flows,” Appl. Opt. 19, 3775–3781 (1980).
    [CrossRef] [PubMed]
  8. F. Beretta, A. Cavaliere, A. D’Alessio, “Ensemble Laser Light Scattering Diagnostics for the Study of Fuel Sprays in Isothermal and Burning Conditions,” in Twentieth Symposium on Combustion (The Combustion Institute, Pittsburgh, 1984, pp. 1249–1258.
  9. R. A. Dobbins, G. S. Jizmagian, “Optical Scattering Cross Sections for Polydispersions of Dielectric Particles,” J. Opt. Soc. Am. 56, 1345–1350 (1966).
    [CrossRef]
  10. J. R. Hodkinson, Aerosol Science, C. N. Davies, Ed. (Academic, New York, 1966), Chap. 10, pp. 290–297.
  11. J. F. Richardson, W. N. Zaki, “Sedimentation and Fluidization: Part I,” Trans. Inst. Chem. Eng. 32, 35–53 (1954).
  12. J. Van de Hulst, Light Scattering by Small Particles (Dover, New York, 1957).
  13. M. Born, E. Wolf, Principles of Optics (Pergamon, London, 1964).
  14. S. Solimeno, B. Crosignani, P. Di Porto, Guiding, Diffraction and Confinement of Optical Radiation (Pergamon, Orlando, 1986).
  15. J. R. Hodkinson, I. Greenleaves, “Computation of Light-Scattering and Extinction by Spheres According to Diffraction and Geometrical Optics, and Some Comparisons with the Mie Theory,” J. Opt. Soc. Am. 53, 577–588 (1963).
    [CrossRef]

1984

F. Beretta, A. Cavaliere, A. D’Alessio, “Drop Size and Concentration in a Spray by Sideward Laser Light Scattering Measurements,” Combust. Sci. Technol. 36, 19–37 (1984).
[CrossRef]

1980

1979

1973

L. Massimilla, “Behaviour of Catalytic Beds of Fine Particles at High Gas Velocities,” AIChE Symp. Ser. 69, 11–13 (1973).

1966

1963

1954

J. F. Richardson, W. N. Zaki, “Sedimentation and Fluidization: Part I,” Trans. Inst. Chem. Eng. 32, 35–53 (1954).

Arena, U.

U. Arena, A. Cammarota, L. Massimilla, D. Pirozzi, “The Hydrodynamics Behaviour of Two Circulating Fluidized Bed Units of Different Sizes,” in Circulating Fluidized Bed Technology II, P. Basu, J. F. Large, Eds. (Pergamon, London, 1988), pp. 223–230.

Ariessohn, P. C.

Beretta, F.

F. Beretta, A. Cavaliere, A. D’Alessio, “Drop Size and Concentration in a Spray by Sideward Laser Light Scattering Measurements,” Combust. Sci. Technol. 36, 19–37 (1984).
[CrossRef]

F. Beretta, A. Cavaliere, A. D’Alessio, “Ensemble Laser Light Scattering Diagnostics for the Study of Fuel Sprays in Isothermal and Burning Conditions,” in Twentieth Symposium on Combustion (The Combustion Institute, Pittsburgh, 1984, pp. 1249–1258.

Born, M.

M. Born, E. Wolf, Principles of Optics (Pergamon, London, 1964).

Cammarota, A.

U. Arena, A. Cammarota, L. Massimilla, D. Pirozzi, “The Hydrodynamics Behaviour of Two Circulating Fluidized Bed Units of Different Sizes,” in Circulating Fluidized Bed Technology II, P. Basu, J. F. Large, Eds. (Pergamon, London, 1988), pp. 223–230.

Cashdollar, K. L.

Cavaliere, A.

F. Beretta, A. Cavaliere, A. D’Alessio, “Drop Size and Concentration in a Spray by Sideward Laser Light Scattering Measurements,” Combust. Sci. Technol. 36, 19–37 (1984).
[CrossRef]

F. Beretta, A. Cavaliere, A. D’Alessio, “Ensemble Laser Light Scattering Diagnostics for the Study of Fuel Sprays in Isothermal and Burning Conditions,” in Twentieth Symposium on Combustion (The Combustion Institute, Pittsburgh, 1984, pp. 1249–1258.

Crosignani, B.

S. Solimeno, B. Crosignani, P. Di Porto, Guiding, Diffraction and Confinement of Optical Radiation (Pergamon, Orlando, 1986).

D’Alessio, A.

F. Beretta, A. Cavaliere, A. D’Alessio, “Drop Size and Concentration in a Spray by Sideward Laser Light Scattering Measurements,” Combust. Sci. Technol. 36, 19–37 (1984).
[CrossRef]

F. Beretta, A. Cavaliere, A. D’Alessio, “Ensemble Laser Light Scattering Diagnostics for the Study of Fuel Sprays in Isothermal and Burning Conditions,” in Twentieth Symposium on Combustion (The Combustion Institute, Pittsburgh, 1984, pp. 1249–1258.

Di Porto, P.

S. Solimeno, B. Crosignani, P. Di Porto, Guiding, Diffraction and Confinement of Optical Radiation (Pergamon, Orlando, 1986).

Dobbins, R. A.

Eustis, R. H.

Greenleaves, I.

Hartge, E.-U.

E.-U. Hartge, D. Rensner, J. Werther, “Solids Concentration and Velocity Patterns in Circulating Fluidized Beds,” in Circulating Fluidized Bed Technology II, P. Basu, A. J. F. Large, Eds. (Pergamon, London, 1988), pp. 165–180.

Hodkinson, J. R.

Holve, D. J.

D. J. Holve, “In Situ Optical Particle Sizing Technique,” J. Energy 4 (4), 176–183 (1980).
[CrossRef]

Jizmagian, G. S.

Lee, C. K.

Massimilla, L.

L. Massimilla, “Behaviour of Catalytic Beds of Fine Particles at High Gas Velocities,” AIChE Symp. Ser. 69, 11–13 (1973).

U. Arena, A. Cammarota, L. Massimilla, D. Pirozzi, “The Hydrodynamics Behaviour of Two Circulating Fluidized Bed Units of Different Sizes,” in Circulating Fluidized Bed Technology II, P. Basu, J. F. Large, Eds. (Pergamon, London, 1988), pp. 223–230.

Pirozzi, D.

U. Arena, A. Cammarota, L. Massimilla, D. Pirozzi, “The Hydrodynamics Behaviour of Two Circulating Fluidized Bed Units of Different Sizes,” in Circulating Fluidized Bed Technology II, P. Basu, J. F. Large, Eds. (Pergamon, London, 1988), pp. 223–230.

Rensner, D.

E.-U. Hartge, D. Rensner, J. Werther, “Solids Concentration and Velocity Patterns in Circulating Fluidized Beds,” in Circulating Fluidized Bed Technology II, P. Basu, A. J. F. Large, Eds. (Pergamon, London, 1988), pp. 165–180.

Richardson, J. F.

J. F. Richardson, W. N. Zaki, “Sedimentation and Fluidization: Part I,” Trans. Inst. Chem. Eng. 32, 35–53 (1954).

Self, S. A.

Singer, J. M.

Solimeno, S.

S. Solimeno, B. Crosignani, P. Di Porto, Guiding, Diffraction and Confinement of Optical Radiation (Pergamon, Orlando, 1986).

Van de Hulst, J.

J. Van de Hulst, Light Scattering by Small Particles (Dover, New York, 1957).

Werther, J.

E.-U. Hartge, D. Rensner, J. Werther, “Solids Concentration and Velocity Patterns in Circulating Fluidized Beds,” in Circulating Fluidized Bed Technology II, P. Basu, A. J. F. Large, Eds. (Pergamon, London, 1988), pp. 165–180.

Wolf, E.

M. Born, E. Wolf, Principles of Optics (Pergamon, London, 1964).

Zaki, W. N.

J. F. Richardson, W. N. Zaki, “Sedimentation and Fluidization: Part I,” Trans. Inst. Chem. Eng. 32, 35–53 (1954).

AIChE Symp. Ser.

L. Massimilla, “Behaviour of Catalytic Beds of Fine Particles at High Gas Velocities,” AIChE Symp. Ser. 69, 11–13 (1973).

Appl. Opt.

Combust. Sci. Technol.

F. Beretta, A. Cavaliere, A. D’Alessio, “Drop Size and Concentration in a Spray by Sideward Laser Light Scattering Measurements,” Combust. Sci. Technol. 36, 19–37 (1984).
[CrossRef]

J. Energy

D. J. Holve, “In Situ Optical Particle Sizing Technique,” J. Energy 4 (4), 176–183 (1980).
[CrossRef]

J. Opt. Soc. Am.

Trans. Inst. Chem. Eng.

J. F. Richardson, W. N. Zaki, “Sedimentation and Fluidization: Part I,” Trans. Inst. Chem. Eng. 32, 35–53 (1954).

Other

J. Van de Hulst, Light Scattering by Small Particles (Dover, New York, 1957).

M. Born, E. Wolf, Principles of Optics (Pergamon, London, 1964).

S. Solimeno, B. Crosignani, P. Di Porto, Guiding, Diffraction and Confinement of Optical Radiation (Pergamon, Orlando, 1986).

J. R. Hodkinson, Aerosol Science, C. N. Davies, Ed. (Academic, New York, 1966), Chap. 10, pp. 290–297.

F. Beretta, A. Cavaliere, A. D’Alessio, “Ensemble Laser Light Scattering Diagnostics for the Study of Fuel Sprays in Isothermal and Burning Conditions,” in Twentieth Symposium on Combustion (The Combustion Institute, Pittsburgh, 1984, pp. 1249–1258.

E.-U. Hartge, D. Rensner, J. Werther, “Solids Concentration and Velocity Patterns in Circulating Fluidized Beds,” in Circulating Fluidized Bed Technology II, P. Basu, A. J. F. Large, Eds. (Pergamon, London, 1988), pp. 165–180.

U. Arena, A. Cammarota, L. Massimilla, D. Pirozzi, “The Hydrodynamics Behaviour of Two Circulating Fluidized Bed Units of Different Sizes,” in Circulating Fluidized Bed Technology II, P. Basu, J. F. Large, Eds. (Pergamon, London, 1988), pp. 223–230.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1

Schematic representation of the measurement volume VM in the light scattering experiment. DS is the diameter of the light beam at the output of the source, DD is the transverse section of the sensible area of the receiver, ϑs is the divergence half-angle of the incident beam, ϑD is the acceptance half-angle of the receiver, Φs is the scattering angle, ds, and dD are the optical path lengths of the incident and scattered beam, respectively.

Fig. 2
Fig. 2

Schematic of the optoelectronic setup: A, laser; B, optical fiber; C, metallic needle probe; D, 41-mm i.d. Plexiglass pipe; E, photodiode; F, scope. L = optical path length.

Fig. 3
Fig. 3

Experimental apparatus: A, laser power supply; B, laser driver; C, laser diode; D, optical fiber; E, metallic needle probe; F, photodiode; G, scope; H, solids feed hopper; L, nets series; M, 41-mm i.d. 1-m high Plexiglas pipe; N, device to carry solids falling along the pipe walls away from the weighing device: O, vessel; P, plate balance.

Fig. 4
Fig. 4

Relationship between the falling velocity U and the solids volumetric concentration Cv,. The relationship is based on the Richardson and Zaki correlation11 referred to as flow through the appartus tested of 90-μm glass bead particles in air.

Fig. 5
Fig. 5

Concentration profiles with no wall effects. Ordinates on the left Cv,0 evaluated by Ē = 1; ordinates on the right Cv,0 evaluated by E = 0.02.

Fig. 6
Fig. 6

Linearity test: the mean values of volumetric concentration C ¯ v , 0 ooptically measured (by our technique) vs the same values C ¯ v , W mechanically measured. These last values have been obtained through weight measurements.

Fig. 7
Fig. 7

Extinction coefficient Ē vs the volumetric concentration Cv,W for glass beads with an average diameter of ~90 μm.

Fig. 8
Fig. 8

Reduction in extinction coefficient (ΔE) due to the collection of scattered light as a function of the semiangle θ subtended at the particle by the receiver: ΔE0 is the contribution due to the collection of diffracted light. (ΔE0 also depends on the size parameter α = πdp/λ and the particles refraction index m; the plot reported is relative to the α ≃ 100 and m = 1.5 case. For α > 100, as in our case, we expect greater values of ΔE0.) ΔE1 is the contribution due to reflection, and ΔE2 is that relative to refraction.

Equations (13)

Equations on this page are rendered with MathJax. Learn more.

V M ~ π 4 ( D s + d s sin ϑ s ) 2 ( D D + d D sin ϑ D ) sin Φ s .
I D = [ S ( d s ) · S ( V M , ϕ ) · S ( d D ) ] · I s ,
T = exp [ - 3 E ( α , m ) C v L 2 d p ] ,
C v = π 6 ( d p a ) 3 ,
T = exp ( - 3 E ¯ C v L 2 d 32 ) ,
E ¯ = 0 E ( α , m ) d p 2 N ( d p ) d d p 0 d p 2 N ( d p ) d d p ,
d 32 = 0 d p 3 N ( d p ) d d p 0 d p 2 N ( d p ) d d p ,
T ( L ) = exp [ - 3 E ¯ 2 d 32 0 L C v ( l ) d l ]
C v ( L ) = 2 d 32 3 E ¯ Δ L ln T ( L ) T ( L + Δ L ) ,
C v ( L ) = 2 d 32 3 E ¯ Δ L ln [ T N ( L ) T N ( L + Δ L ) ] .
T N ( x ) = T ( x ) T ( x ) c v = 0
C v ( L ) = K ( C v ) ln [ T N ( L ) T N ( L + Δ L ) ] ,
C v , W = W ρ S U ( C v , W ) t m ,

Metrics