Improved void fraction determination by means of multibeam gamma-ray attenuation measurements
Autor: | Geir Anton Johansen, E Åbro |
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Rok vydání: | 1999 |
Předmět: |
Physics
Void (astronomy) Scintillation business.industry Astrophysics::High Energy Astrophysical Phenomena Detector Computer Science Applications Optics Modeling and Simulation Measuring principle Electromagnetic shielding Fluid dynamics Densitometer Electrical and Electronic Engineering Porosity business Instrumentation |
Zdroj: | Flow Measurement and Instrumentation. 10:99-108 |
ISSN: | 0955-5986 |
Popis: | Gamma-ray densitometry is a frequently used non-intrusive method for determining void fraction in two- and multi-phase gas liquid pipe flows. The traditional gamma-ray densitometer using a 137 Cs source and a scintillation PMT detector has proved itself reliable and robust. This paper presents a method using a low energy source ( 241 Am), which offers the advantages of reduced size due to reduced shielding requirements, compact detectors, and lesser dependence on flow regime, due to its multibeam measurement configuration. These are important aspects with regard to future subsea and down-hole fluid flow measurement applications. The performance of single-beam and the compact multi-beam low-energy gamma-ray measurement principles was compared. Consideration of the measurement volume, defined by the detector area and the radiation beam, demonstrated the flow regime dependency of single-beam gamma-ray measurement principles. With the multi-beam low-energy gamma-ray measurement principle, the dependence on flow regime is negligible when several detector responses are combined. Use of phantoms and one movable detector verified the multi-beam gamma-ray measurement principle. The detector responses at several positions around the pipe were obtained for different flow regimes and void fractions. |
Databáze: | OpenAIRE |
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