Experimental measurements of the void fraction in two-phase single component upward flow of both helium and nitrogen were carried out using the capacitance probe technique. An electronic circuit was designed and constructed to accurately detect small changes in the dielectric constant resulting from
How to measure void fraction of two-phase cryogenic flows
โ Scribed by Yu.P. Filippov
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 404 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0011-2275
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โฆ Synopsis
The report presents the experience in the ยฎeld of designing, manufacturing and testing the void fraction sensors of round and annular cross-sections for research purposes and practical applications. These sensors are of radio frequency type with a uniform electric ยฎeld within the measuring volume, and their readings depend on the dielectric permittivity of the media ยฎlling the sensitive part. The measuring system and method to calibrate these sensors are described. The temperature sensors used to measure the temperatures of the void fraction sensor body and the cryogenic ยฏows are also presented. The operational characteristics of the radio frequency (RF)-systems for TESLA Test Facility cooled with two-phase superยฏuid helium at 1.8 K, Nuclotron and UNK cooled with two-phase helium at 4.5 K, the installation to separate isotopes of hydrogen at 22 K, etc. are reported.
๐ SIMILAR VOLUMES
A model has been developed to predict average void-fractions in horizontal and vertical two-phase flow based on a single flow parameter K and the slip velocity. The model is based on the assumptions that the radial distributions of liquid velocity and void-fraction can be represented by parabolic-ty
published the paper "A model to predict void-fraction in two-phase flow"[ I]. This model is based on a rather sophisticated assumption of parabolic void-fraction and liquid velocity profiles. Although it was shown121, 131 that the liauid velocitv orofde is less flat in