A novel optical technique for accurate planar measurements of film-thickness and velocity in annular flows

dc.contributor.authorCharogiannis, A.en
dc.contributor.authorAn, J.S.en
dc.contributor.authorMarkides, C.N.en
dc.date.accessioned2017-09-19T12:48:30Z
dc.date.available2017-09-19T12:48:30Z
dc.date.issued2017en
dc.descriptionPapers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .en
dc.description.abstractGas-liquid annular flow is one of many possible two-phase flow regimes that are encountered in the (e.g., parabolic collector) solar fields of direct-evaporation concentrated solar-power (CSP) plants. Conventional planar laser-induced fluorescence (PLIF) has been used previously to investigate the liquid film topology (i.e. film thickness) in annular flows, however, limitations have been found regarding the accurate identification of the gas-liquid interface with this technique, especially when the interface is smooth. Therefore, a novel variation of PLIF, which we refer to as structured planar laser-induced fluorescence (S-PLIF), has been developed to overcome these limitations. In this study, S-PLIF is used to investigate the topology of falling films in a vertical pipe over the range ReL ≈ 150 – 1500. Comparison of S-PLIF at two different angles (70° and 90°) shows that the technique performs better with an observation angle of 70° as this minimizes the distortions caused by the radial liquid film structure. In addition, S-PLIF70 shows good agreement with data from other techniques that have shown reliability when studying smooth films over the same range of conditions.en
dc.description.sponsorshipInternational centre for heat and mass transfer.en
dc.description.sponsorshipAmerican society of thermal and fluids engineers.en
dc.format.extent5 pagesen
dc.format.mediumPDFen
dc.identifier.urihttp://hdl.handle.net/2263/62371
dc.language.isoenen
dc.publisherHEFATen
dc.rightsUniversity of Pretoriaen
dc.subjectNovel optical techniqueen
dc.subjectAccurate planar measurementsen
dc.subjectAnnular flowsen
dc.subjectVelocityen
dc.subjectFilm-thicknessen
dc.titleA novel optical technique for accurate planar measurements of film-thickness and velocity in annular flowsen
dc.typePresentationen

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
Charogiannis_Novel_2017.pdf
Size:
748.67 KB
Format:
Adobe Portable Document Format
Description:
Presentation