The use of optic fiber probes for the measurement of dilute particle concentrations: calibration and application to gas-fluidized bed carryover

Matsuno, Yasunari; Yamaguchi, Hisamori; Oka, Toshiomi; Kage, Hiroyuki; Higashitani, Ko

doi:10.1016/0032-5910(83)85005-0

Cited by 45 publications

(22 citation statements)

References 16 publications

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“…Our own calibration experiments with suspensions of FCC particles in water suggest, in addition, that the reflectivity of wet particles may differ from that of dry powder, introducing further complications to liquidbed calibrations. Matsuno et al (1983) calibrated their fiber probe in air by dropping particles from a vibrating-sieve apparatus past a probe positioned far enough below the particles' release point that the particles would be at a terminal velocity. Knowing the mass of particles dropped in a given time and the particle density, the time-mean concentration of particles passing the probe could be estimated, and a calibration curve constructed.…”

Section: Fiber-optic Voidage Probementioning

confidence: 99%

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

Oelfke¹,

Torczynski²,

O’Hern³

et al. 2006

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An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow™.

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Section: Fiber-optic Voidage Probementioning

confidence: 99%

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

Oelfke¹,

Torczynski²,

O’Hern³

et al. 2006

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“…Although numerous investigations have utilized fiber optic probes for obtaining direct measurements of solid concentration (Louge 1997;van Ommen and Mudde 2008), several works have noted the inefficacy of the fiber optic probe to give absolute concentration values due to the problematic calibration procedures involved (Matsuno, Yamaguchi et al 1983;Herbert, Gauthier et al 1994;. Accordingly, in this work, instead of attempting to FINAL TECHNICAL REPORT 166 calibrate the fiber optic probe signals to obtain absolute solid concentration values (since, for example, continual bombardment of the probe tip by glass particles may alter the baseline signal with time), a wavelet decomposition (Mallat 1998) of the raw signal is instead used as an indicator of relative solid concentration (i.e., dense phase versus dilute phase), as detailed below.…”

Section: Pitot Tube and Extraction Probementioning

confidence: 99%

“…Figure 140 contains the fiber optic traces collected at riser wall (subplots on left: r/R = 0.96) and riser center (subplots on right: r/R = 0.0) for the three materials for the upper region of the riser where the reverse core-annulus behavior was observed for two of the three materials (i.e., large glass beads and HDPE). For the large glass material, comparison of Figure 140a Keeping in mind the potential challenges involved with calibration of fiber optic voltage for absolute concentration values (Matsuno, Yamaguchi et al 1983;Herbert, Gauthier et al 1994;, further analysis of the fiber optic data using wavelet decomposition was carried out since it gives information on relative concentration rather than absolute values. The wavelet decomposition results again confirm the presence of the reverse core-annulus phenomenon observed with the Pitot tube/extraction probe.…”

Section: Dense Versus Dilute Flow Conditions Via Fiber Optic Probementioning

confidence: 99%

“…The underlying principle of the fiber optic probe is such that a higher voltage signal is obtained from the receiving fiber when light emitted from the light-source fiber is blocked, as occurs when the probe is surrounded by a denser (particle-rich) phase. On the other hand, a lower voltage signal is obtained when light from the emitter is relatively unobstructed, which occurs when the probe tip is in a more dilute (gas-rich) phase.Although numerous investigations have utilized fiber optic probes for obtaining direct measurements of solid concentration (Louge 1997; van Ommen and Mudde 2008), several works have noted the inefficacy of the fiber optic probe to give absolute concentration values due to the problematic calibration procedures involved (Matsuno, Yamaguchi et al 1983;Herbert, Gauthier et al 1994;. Accordingly, in this work, instead of attempting to 166 calibrate the fiber optic probe signals to obtain absolute solid concentration values (since, for example, continual bombardment of the probe tip by glass particles may alter the baseline signal with time), a wavelet decomposition(Mallat 1998) of the raw signal is instead used as an indicator of relative solid concentration (i.e., dense phase versus dilute phase), as detailed below.…”

mentioning

confidence: 99%

“…Before discussing which wavelet decomposition scale is appropriate to use as the threshold for cluster detection, it is worth noting that efforts have been made by previous researchers towards calibrating the voltage signals obtained from fiber optic probes to obtain solids concentration traces (Louge 1997; van Ommen and Mudde 2008). Nonetheless, several works have noted the inefficacy of the fiber optic probe to give absolute concentration values due to the associated problematic calibration (Matsuno, Yamaguchi et al 1983;Herbert, Gauthier et al 1994;. Consequently, in this work, instead of calibrating the fiber optic probe signals to obtain quantitative values (magnitudes) for solids concentration, the raw voltage traces were instead analyzed for relative changes in concentration (via wavelet analysis) in order to obtain information on clustering.…”

mentioning

confidence: 99%

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Development, Verification, and Validation of Multiphase Models for Polydisperse Flows

Hrenya¹,

Cocco²,

Fox³

et al. 2011

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This report describes in detail the technical findings of the DOE Award entitled "Development, Verification, and Validation of Multiphase Models for Polydisperse Flows." The focus was on high-velocity, gas-solid flows with a range of particle sizes. A complete mathematical model was developed based on first principles and incorporated into MFIX. The solid-phase description took two forms: the Kinetic Theory of Granular Flows (KTGF) and Discrete Quadrature Method of Moments (DQMOM). The gas-solid drag law for polydisperse flows was developed over a range of flow conditions using Discrete Numerical Simulations (DNS). These models were verified via examination of a range of limiting cases and comparison with Discrete Element Method (DEM) data. Validation took the form of comparison with both DEM and experimental data. Experiments were conducted in three separate circulating fluidized beds (CFB's), with emphasis on the riser section. Measurements included bulk quantities like pressure drop and elutriation, as well as axial and radial measurements of bubble characteristics, cluster characteristics, solids flux, and differential pressure drops (axial only). Monodisperse systems were compared to their binary and continuous particle size distribution (PSD) counterparts. The continuous distributions examined included Gaussian, lognormal, and NETLprovided data for a coal gasifier.FINAL TECHNICAL 4 DE-FC26-07NT43098 5 EXECUTIVE SUMMARYThis report is the final technical report for the award DE-FC26-07NT43098 entitled "Development, Verification, and Validation of Multiphase Models for Polydisperse Flows." Below is a summary of work completed under the grant for each of the major goals. Goal I: Continuum Theory for Solid PhaseTwo separate and complementary continuum theories were derived to model polydisperse solids: the kinetic theory of granular flow (KTGF) and the discrete quadrature method of moments (DQMOM). Both theories are based on first principles with no adjustable parameters. The polydisperse KTGF and DQMOM were then encoded in MFIX, and underwent a wide range of verification testing to ensure, to the best possible extent, that no coding errors were present. These verification tests included both granular and gas-solid flows, including cases where an analytical solution and/or DEM (discrete element method) data and/or simple test cases. For the case of KTGF, another set of constitutive equations were derived which rigorously incorporated the gas phase for a simplified case of monodisperse systems at low Reynolds numbers. This derivation used the acceleration model developed in Task 2 from direct numerical simulations (DNS) in the starting kinetic equation, and indicated the effect of the fluid phase on the resulting constitutive relations. Goal II: Improved Gas-Particle Drag Laws -effect of particle size distributionIn this portion of the effort, two types of direct numerical simulations (DNS) were used to extract the drag force experienced by particles in a polydisperse suspension. These two methods, na...

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Calibration of solids concentration optical fibre probes with solids‐polymer blocks

2021

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Owing to the determinant effects of the local distribution of solids concentration on transport phenomena, particularly in gas‐solids flows in such processing units as gas‐solid fluidized beds and pneumatic conveying lines, its accurate measurement has received considerable attention. Despite the widespread applications of optical fibre probes for the measurement of local solids concentration, these instruments may create measurement uncertainties due to their structural designs and challenges in their accurate calibrations. Several calibration methods have been proposed in the literature, while they need to be further improved. In the present study, we calibrated in‐house, fabricated, solids concentration mixed parallel optical fibre probes by two sets of solids‐polymer blocks covering solids volume fractions in the range of 0‐0.30. The uniform blocks were produced by a twin‐screw extruder and an injection moulding machine. FCC particles, 86 μm in diameter, formed the dispersed solids in the blocks, while poly styrene and poly methyl methacrylate were separately acting as the transparent medium. They helped us investigate the effects of the refractive index of the medium and the probe tip design on the calibration curve. The blind distance (zone) in front of the adopted probes was determined, at about 0.70 mm, upon measuring their reflective curves. Two glass windows with 1.00 and 1.60 mm thicknesses were separately installed at the tip of a probe to study their effects on the calibration curve. Experimental results indicated that in the absence of a glass window, the probes' voltage readings varied nonlinearly with solids concentration, the voltage readings were higher for blocks with a higher refractive index of the transparent medium, while the normalized calibration curves were similar for both sets of solids‐polymer blocks. In addition, the extent of the uniform distribution of illuminating and reflecting fibre strands at the tip of a mixed parallel optical fibre probe can change the degree of nonlinearity of its calibration curve. The application of glass windows thicker than the blind distance decreased the degree of nonlinearity of the calibration curve, yet did not completely eliminate it.

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The use of optic fiber probes for the measurement of dilute particle concentrations: calibration and application to gas-fluidized bed carryover

Cited by 45 publications

References 16 publications

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

Development, Verification, and Validation of Multiphase Models for Polydisperse Flows

Calibration of solids concentration optical fibre probes with solids‐polymer blocks

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