Advanced tomographic flow diagnostics for opaque multiphase fluids

Torczynski, J. R.; O’Hern, Timothy J.; Adkins, Douglas R.; Jackson, Nancy B.; Shollenberger, K. A.

doi:10.2172/481578

Cited by 12 publications

(25 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For these reasons, a number of gammadensitometry tomography systems have been assembled and applied for multiphase flow measurement worldwide (e.g., Petrick and Swanson, 1958;van Santen et al, 1997;Mudde et al, 1999). Sandia National Laboratories has experience with multiphase GDT in two-and threephase flows in bubble columns Torczynski et al, 1997;George et al, 2000ab, 2001). The GDT system designed and assembled for this project was based on this experience.…”

Section: Gamma-densitometry Tomographymentioning

confidence: 99%

See 1 more Smart Citation

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

Oelfke¹,

Torczynski²,

O’Hern³

et al. 2006

View full text Add to dashboard Cite

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™.

show abstract

Section: Gamma-densitometry Tomographymentioning

confidence: 99%

“…The generalized equations for relating the coefficients of an even polynomial function and its Abel transform are given by Torczynski et al (1997), and here they are related by: .10 includes a representative radial profile of solids fraction measured using GDT when an asymmetric fit was used.…”

Section: Gdt Reconstructionmentioning

confidence: 99%

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

Oelfke¹,

Torczynski²,

O’Hern³

et al. 2006

View full text Add to dashboard Cite

show abstract

“…There is a need for direct knowledge of the internal flow characteristics in these types of multiphase flows to enable improved design and increased operational efficiency of existing and new processing equipment. Flow characteristics required to predict performance of multiphase processes include spatial distribution of the phases (spatial volumetric phase fractions), flow regime, interfacial area, and relative velocities between the phases, among others (George et al 1999;Torczynski et al 1997). Knowing the spatial distribution of the phases is particularly important since nonuniform distributions of the gas phase would reduce the interfacial area between phases available for chemical reaction or conversion and may result in recirculating flows creating spatially nonuniform reaction zones or concentrations (Jackson et al 1996).…”

Section: Contentsmentioning

confidence: 99%

“…Brief reviews of the hydrodynamics and modeling of multiphase flows in vertical bubble columns can be found in the literature (George et al 2000c;Shah and Deckwer 1983;Torczynski et al 1997). Here, a brief review of the theories behind EIT and GDT measurements is presented.…”

Section: Theorymentioning

confidence: 99%

“…(5)], an axisymmetric parabolic profile was assumed in this study for the GDT reconstructions. The assumption of an axisymmetric parabolic profile is valid for many vertical multiphase flows when averaged over long time scales (Torczynski et al 1997). Thus, this is an appropriate assumption for use with GDT since it is an inherently time-averaged measurement.…”

Section: Gamma-densitometry Tomography (Gdt)mentioning

confidence: 99%

See 1 more Smart Citation

Electrical-Impedance Tomography for Opaque Multiphase Flows in Metallic (Electrically-Conducting) Vessels

Liter¹,

Torczynski²,

Shollenberger³

et al. 2002

View full text Add to dashboard Cite

A novel electrical-impedance tomography (EIT) diagnostic system, including hardware and software, has been developed and used to quantitatively measure material distributions in multiphase flows within electrically-conducting (i.e., industrially relevant or metal) vessels. The EIT system consists of energizing and measuring electronics and seven ring electrodes, which are equally spaced on a thin nonconducting rod that is inserted into the vessel. The vessel wall is grounded and serves as the ground electrode. Voltage-distribution measurements are used to numerically reconstruct the time-averaged impedance distribution within the vessel, from which the material distributions are inferred. Initial proof-of-concept and calibration was completed using a stationary solid-liquid mixture in a steel bench-top standpipe. The EIT system was then deployed in Sandia's pilot-scale slurry bubble-column reactor (SBCR) to measure material distributions of gas-liquid two-phase flows over a range of column pressures and superficial gas flow rates. These two-phase quantitative measurements were validated against an established 3 gamma-densitometry tomography (GDT) diagnostic system, demonstrating agreement to within 0.05 volume fraction for most cases, with a maximum difference of 0.15 volume fraction. Next, the EIT system was combined with the GDT system to measure material distributions of gasliquid-solid three-phase flows in Sandia's SBCR for two different solids loadings. Accuracy for the three-phase flow measurements is estimated to be within 0.15 volume fraction. The stability of the energizing electronics, the effect of the rod on the surrounding flow field, and the unsteadiness of the liquid temperature all degrade measurement accuracy and need to be explored further. This work demonstrates that EIT may be used to perform quantitative measurements of material distributions in multiphase flows in metal vessels.

show abstract

Quantitative measurement of solids distribution in gas–solid riser flows using electrical impedance tomography and gamma densitometry tomography

Tortora

Ceccio

O’Hern

et al. 2006

International Journal of Multiphase Flow

View full text Add to dashboard Cite

Advanced tomographic flow diagnostics for opaque multiphase fluids

Cited by 12 publications

References 40 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).

Electrical-Impedance Tomography for Opaque Multiphase Flows in Metallic (Electrically-Conducting) Vessels

Quantitative measurement of solids distribution in gas–solid riser flows using electrical impedance tomography and gamma densitometry tomography

Contact Info

Product

Resources

About