Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

PIV Measurement of Heat Transfer Deterioration Phenomena

Get access (open in a dialog) DOI: 10.1615/IHTC15.ees.009058
pages 2255-2262

Abstrakt

Accurate understanding of supercritical pressure heat transfer characteristics is important for reliable design of supercritical pressure boiler. Over the past years, several studies have been made to investigate forced convection heat transfer coefficient of supercritical pressure water and it has been recognized that heat transfer coefficient decreased drastically near the pseud-critical temperature where coolant properties changed drastically. This phenomenon is called Heat Transfer Deterioration (HTD). Recently some numerical simulation results of HTD are reported, and shows that the velocity distribution of upward flow water in a tube becomes flat at HTD, because of water properties changes near the wall and buoyancy lifting force increases. In order to confirm this phenomenon experimentally, we have applied PIV(Particle Image Velocimetry) to measure velocity distribution change of upward flow air in a tube. The air flow test equipment was designed that, Grashof Number (Gr) and Reynolds Number (Re) are modified to HTD phenomenon. This experiment showed several unique data of velocity distribution change. We expect these experimental data will help us to understand HTD in more detail and lead to more reliable design of boilers.