Convective condensation inside horizontal smooth and microfin tubes
Författare
Summary, in English
An experimental investigation was performed for convective condensation of R410A
inside one smooth tube (3.78 mm, inner diameter) and six microfin tubes (4.54, 4.6 and
8.98 mm, fin root diameter) of different geometries for mass fluxes ranging from 99 to 603
kg m-2s-1. The experimental data were analyzed with updated flow pattern maps and
evaluated with existing correlations. The heat transfer coefficient in the microfin tubes
decreases at first and then increases or flattens out gradually as mass flux decreases.
This obvious non-monotonic heat transfer coefficient-mass flux relation may be explained
by the complex interactions between the microfins and the fluid, mainly by surface
tension effects. The heat transfer enhancement mechanism in microfin tubes is mainly
due to the surface area increase at large mass fluxes, while liquid drainage by surface
tension and interfacial turbulence enhance heat transfer greatly at low mass fluxes.
inside one smooth tube (3.78 mm, inner diameter) and six microfin tubes (4.54, 4.6 and
8.98 mm, fin root diameter) of different geometries for mass fluxes ranging from 99 to 603
kg m-2s-1. The experimental data were analyzed with updated flow pattern maps and
evaluated with existing correlations. The heat transfer coefficient in the microfin tubes
decreases at first and then increases or flattens out gradually as mass flux decreases.
This obvious non-monotonic heat transfer coefficient-mass flux relation may be explained
by the complex interactions between the microfins and the fluid, mainly by surface
tension effects. The heat transfer enhancement mechanism in microfin tubes is mainly
due to the surface area increase at large mass fluxes, while liquid drainage by surface
tension and interfacial turbulence enhance heat transfer greatly at low mass fluxes.
Avdelning/ar
Publiceringsår
2014
Språk
Engelska
Publikation/Tidskrift/Serie
Journal of Heat Transfer
Volym
136
Issue
5
Dokumenttyp
Artikel i tidskrift
Förlag
American Society Of Mechanical Engineers (ASME)
Ämne
- Energy Engineering
Status
Published
Forskningsgrupp
- heat transfer
ISBN/ISSN/Övrigt
- ISSN: 0022-1481