Molten salt dynamics in glass melts using millimeter-wave emissivity measurements

Woskov, P.; Sundaram, S. K.; Daniel, William E.; Miller, Donald H.

doi:10.1016/j.jnoncrysol.2004.05.009

Cited by 12 publications

(6 citation statements)

References 3 publications

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“…This puts the emissivity in the range of 0.66 ± 0.03, assuming that the reflected power into the waveguide could be up to 2 to 3 times higher than the measured TE 02 reflection shown in Figure 7. This emissivity is consistent with earlier measurements of 0.64 ± 0.05 at 137 GHz for black glass melt composed of metal oxides found in rocks [18].…”

Section: Power and Temperature Measurementssupporting

confidence: 93%

Millimeter-Wave Heating, Radiometry, and Calorimetry of Granite Rock to Vaporization

Woskov

Michael

2011

J Infrared Milli Terahz Waves

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Abstract:Millimeter-wave (MMW) technologies can provide unique heating and diagnostic capabilities to research the thermal dynamics of materials to extreme temperatures. The MMW properties of rocks in the molten state up to their vaporization temperatures are not well known. Using a 28 GHz gyrotron beam collinear with a 130 GHz radiometry view in a calorimetric chamber, the transitions of granite rock specimens through solid phases, melting, and vaporization were observed, including release of trapped trace gas (< 0.07%). The 28 GHz emissivity of molten granite was observed to be approximately constant at 0.66 ± 0.03 up to vaporization where it increased to 0.70 ± 0.03 at an equilibrated temperature of 2710 ± 120 °C. An analysis of the thermal power balance during a 76 s steady state vaporization time period indicates that the MMW emissivity of the molten granite is larger than in the infrared. The observations support the possibility that MMW thermal ablative penetration into hot crystalline rock formations could be a more practical approach than infrared laser drilling to access deep resources.

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Section: Power and Temperature Measurementssupporting

confidence: 93%

Millimeter-Wave Heating, Radiometry, and Calorimetry of Granite Rock to Vaporization

Woskov

Michael

2011

J Infrared Milli Terahz Waves

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“…11 It was later found that apparently violent changes in short-term emissivity were due to abrupt changes in the coupling factor due to melting and foaming rather than to real emissivity changes (see Results and Discussion).…”

Section: B Theoretical Basismentioning

confidence: 91%

“…Interferometric capabilities derive from a narrowband local oscillator (LO) probe at 137 GHz leaked from the heterodyne receiver, and the mixed probe/ return "video" channels allow measurement of volume expansion, level change, and viscosity. 11,12 The viscosity is determined by measuring the velocity of flow of the melt into a waveguide and knowing the density of the melt.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous measurement of temperature and emissivity of lunar regolith simulant using dual-channel millimeter-wave radiometry

McCloy

Sundaram

Matyáš

et al. 2011

Review of Scientific Instruments

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Millimeter wave (MMW) radiometry can be used for simultaneous measurement of emissivity and temperature of materials under extreme environments (high temperature, pressure, and corrosive environments). The state-of-the-art dual channel MMW passive radiometer with active interferometric capabilities at 137 GHz described here allows for radiometric measurements of sample temperature and emissivity up to at least 1600 °C with simultaneous measurement of sample surface dynamics. These capabilities have been used to demonstrate dynamic measurement of melting of powders of simulated lunar regolith and static measurement of emissivity of solid samples. The paper presents the theoretical background and basis for the dual-receiver system, describes the hardware in detail, and demonstrates the data analysis. Post-experiment analysis of emissivity versus temperature allows further extraction from the radiometric data of millimeter wave viewing beam coupling factors, which provide corroboratory evidence to the interferometric data of the process dynamics observed. These results show the promise of the MMW system for extracting quantitative and qualitative process parameters for industrial processes and access to real-time dynamics of materials behavior in extreme environments.

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“…The mixing of the reflected LO with the LO causes interference fringes in the "video" channels that make possible the measurement of volume expansion, level change, and viscosity [5,9]. At normal incidence, the signal reflects off the object of interest, returns via the same channel through the horn and into a mixer where it is converted to a direct current (DC) signal ("video"), is routed through a lock-in amplifier to detect the chopper-modulated part, then monitored by a computer through a general purpose interface bus (GPIB).…”

Section: Millimeter-wave Radiometrymentioning

confidence: 99%

“…One alternative for monitoring high temperature industrial processing such as nuclear waste vitrification [4,5] and coal gasification [6] is millimeter-wave (MMW) technology. The main advantage of millimeter-wave technology is that the wavelengths (10-0.3 mm, 30-1000 GHz) are long enough to penetrate paths obscured by dust, smoke, and debris in the visible and infrared yet short enough for spatially resolved measurements (<5 mm).…”

mentioning

confidence: 99%

High Temperature Millimeter Wave Radiometric and Interferometric Measurements of Slag-Refractory Interaction for Application to Coal Gasifiers

McCloy

Crum

Sundaram

et al. 2011

J Infrared Milli Terahz Waves

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Millimeter wave (MMW) radiometry can be used for simultaneous measurement of emissivity and temperature of materials under extreme environments such as in slagging coal gasifiers, where sensors have been identified as a key enabling technology need for process optimization. We present a dual-channel MMW heterodyne radiometer with active interferometric capability that allows simultaneous measurements of sample temperature, emissivity, and flow dynamics. Interferometric capability at 137 GHz is supplied via a probe signal originating from a local oscillator allowing monitoring of sample dynamics such as volume expansion and thickness change. This capability has been used to monitor characteristic behavior between refractories and slag such as slag infiltration, slag melting, viscous flow, foaming, and crucible corrosion by the molten slag. These results show the promise of the MMW system for extracting process parameters from operating slagging coal gasifiers, providing valuable information for process efficiency, control, and increased productivity.

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Molten salt dynamics in glass melts using millimeter-wave emissivity measurements

Abstract: A novel application of millimeter-wave radiometry has been made for the first time to non-contact detection and monitoring of molten salt layer formation on a nuclear waste glass melt (without the nuclear waste) in a joule-heated melter, which could eventually be

Cited by 12 publications

References 3 publications

Millimeter-Wave Heating, Radiometry, and Calorimetry of Granite Rock to Vaporization

Millimeter-Wave Heating, Radiometry, and Calorimetry of Granite Rock to Vaporization

Simultaneous measurement of temperature and emissivity of lunar regolith simulant using dual-channel millimeter-wave radiometry

High Temperature Millimeter Wave Radiometric and Interferometric Measurements of Slag-Refractory Interaction for Application to Coal Gasifiers

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