Experimental study of inverted annular film boiling in a vertical tube cooled by R-134a

► Heat transfer coefficient vs. quality curve can be divided into four regions depending on the flow regime. ► Film boiling heat transfer coefficient increases with increasing pressure and mass flux. ► Heat flux has weak effect on film boiling heat transfer coefficient. ► Inlet subcooling affects he...

Full description

Saved in:
Bibliographic Details
Published in:International journal of multiphase flow 2011, Vol.37 (1), p.67-75
Main Authors: Nakla, Meamer El, Groeneveld, D.C., Cheng, S.C.
Format: Article
Language:English
Subjects:
Annular
Applied sciences
Energy
Energy. Thermal use of fuels
Equivalence
Exact sciences and technology
Film boiling
Flux
Heat transfer
Hot-patch techniques
Inlets
Inverted annular film boiling
Theoretical studies. Data and constants. Metering
Trends
Tubes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:► Heat transfer coefficient vs. quality curve can be divided into four regions depending on the flow regime. ► Film boiling heat transfer coefficient increases with increasing pressure and mass flux. ► Heat flux has weak effect on film boiling heat transfer coefficient. ► Inlet subcooling affects heat transfer coefficient just downstream of CHF location. An experimental investigation of inverted annular film boiling heat transfer has been performed for vertical up-flow in a round tube. The experiments used R-134a coolant and covered a pressure range of 640–2390 kPa (water equivalent range: 4000–14,000 kPa) and a mass flux range of 500–4000 kg m −2 s −1 (water equivalent range: 700–5700 kg m −2 s −1). The inlet qualities of the tests ranged from −0.75 to −0.03. The hot-patch technique was used to obtain the subcooled film boiling measurements. It was found that the heat transfer vs. quality curve can be divided into four different regions, each characterized by a different mechanisms and trends. These regions are dependent on pressure, mass flux and local quality. A detailed examination of the parametric trends of the heat transfer coefficient with respect to mass flux, inlet quality, heat flux and pressure was performed; reasonably good agreement between observed trends and those reported in the literature were noted.
ISSN:0301-9322
1879-3533
DOI:10.1016/j.ijmultiphaseflow.2010.08.006