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Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column

Abstract

In this work the possibility of the use of gamma radiation in investigating bubbles in a large three dimensional gas-fluidised bed was examined. A measuring system was designed based upon the absorption of gamma radiation. As high energy (>100 keV) gamma radiation penetrates deeply into matter, it can be used to scan through a gas-solid fluidised bed. The attenuation of a beam of mono-energetic photons is related to the amount of solid particles in the path of the beam. With the gamma absorption technique two parameters can be determined: The void fraction and the bubble velocity. With one narrow beam of gamma radiation a chordal void fraction can be measured in the homogeneous part of the bed. An optimalisation procedure for the void fraction determination led to the choice of Cs-137 as radiation source. This optimalisation procedure concerned minimizing of the standard deviation in the determined chordal void fraction as a function of the energy of gamma radiation. With two narrow parallel beams placed at a distance of 12 cm above each other a bubble velocity can be obtained. A cross-correlation between the two detector responses gives the time shift between the two responses. The system was designed for velocity  More>>
Authors:
Hoogeveen, M O [1] 
  1. Technische Univ. Delft (Netherlands). Lab. voor Fysische Technologie
Publication Date:
Dec 01, 1993
Product Type:
Thesis/Dissertation
Report Number:
INIS-mf-15156
Reference Number:
SCA: 420400; PA: AIX-27:031601; EDB-96:073654; NTS-96:017801; SN: 96001578359
Resource Relation:
Other Information: DN: Appendices partially in Dutch.; TH: Graduation report.; PBD: Dec 1993
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; FLUIDIZED BEDS; VOID FRACTION; BUBBLES; CESIUM 137; FLUIDIZATION; GAMMA RADIATION; MEASURING METHODS; RADIATION SOURCES; THERMAL COLUMNS; VELOCITY; VOIDS
OSTI ID:
216905
Research Organizations:
Technische Univ. Delft (Netherlands). Faculty of Applied Physics
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Other: ON: DE96620745; TRN: NL96F4902031601
Availability:
INIS; OSTI as DE96620745
Submitting Site:
NLN
Size:
102 p.
Announcement Date:

Citation Formats

Hoogeveen, M O. Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column. Netherlands: N. p., 1993. Web.
Hoogeveen, M O. Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column. Netherlands.
Hoogeveen, M O. 1993. "Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column." Netherlands.
@misc{etde_216905,
title = {Design of gamma radiation equipment for studying a bubbling gas fluidized bed. Determination of a radial void fraction profile and bubble velocities in a 0.40 m column}
author = {Hoogeveen, M O}
abstractNote = {In this work the possibility of the use of gamma radiation in investigating bubbles in a large three dimensional gas-fluidised bed was examined. A measuring system was designed based upon the absorption of gamma radiation. As high energy (>100 keV) gamma radiation penetrates deeply into matter, it can be used to scan through a gas-solid fluidised bed. The attenuation of a beam of mono-energetic photons is related to the amount of solid particles in the path of the beam. With the gamma absorption technique two parameters can be determined: The void fraction and the bubble velocity. With one narrow beam of gamma radiation a chordal void fraction can be measured in the homogeneous part of the bed. An optimalisation procedure for the void fraction determination led to the choice of Cs-137 as radiation source. This optimalisation procedure concerned minimizing of the standard deviation in the determined chordal void fraction as a function of the energy of gamma radiation. With two narrow parallel beams placed at a distance of 12 cm above each other a bubble velocity can be obtained. A cross-correlation between the two detector responses gives the time shift between the two responses. The system was designed for velocity measurements in the non-homogeneous part of the column. A simulation of the two beam measurement method for an air fluidized bed, 0.40 m in diameter, of polystyrene particles led to the choice of 100 mCi for the source strength for each of the two Cs-137 sources. For a 100 mCi Cs-137 source a shielding of 8 cm of lead is necessary to comply with safety regulations, concerning the use of radioactive materials. A source holder was designed, containing two encapsulated 100 mCi Cs-137 sources, in accordance with the regulations in the licence of the Delft University of Technology for the use of encapsulated sources. (orig.).}
place = {Netherlands}
year = {1993}
month = {Dec}
}