Laminar Friction Factors and Colburn Factors for Ducts with Advanced Boundary Conditions
Author
Editor
- G.P. Celata
Summary, in English
Ducts of various geometrical cross sections appear extensively in engineering applications like heat exchangers. In the
available literature analytical, numerical and experimental data are available for the friction factor and the Colburn factor for a
variety of thermal boundary conditions. Results for fully developed cases are commonly available, but also for the thermally
and hydrodynamically developing entrance regions. However, results are not available yet for the cases with advanced
boundary conditions, i.e., having a mixture of uniform heat flux, wall temperature conditions and thermal insulation on the
walls. To complicate the situation further, mass transfer may appear at one or more walls, and buoyancy effects can be
significant in some applications. Such effects are presented.
This paper presents recent numerical investigations and results from the authors. The origin of these advanced boundary
conditions is not in the pure heat exchanger area, but rather from recent developments in the heat and mass transfer analysis in
the emerging area of fuel cells. The comparison with conventional cases and the discussion of the significance of the advanced
boundary conditions are believed to be of key interest to the heat exchanger community as well. The correlations as function
of aspect ratio, base-angle and wall Reynolds number are included in the paper, and can be applied for design purposes.
available literature analytical, numerical and experimental data are available for the friction factor and the Colburn factor for a
variety of thermal boundary conditions. Results for fully developed cases are commonly available, but also for the thermally
and hydrodynamically developing entrance regions. However, results are not available yet for the cases with advanced
boundary conditions, i.e., having a mixture of uniform heat flux, wall temperature conditions and thermal insulation on the
walls. To complicate the situation further, mass transfer may appear at one or more walls, and buoyancy effects can be
significant in some applications. Such effects are presented.
This paper presents recent numerical investigations and results from the authors. The origin of these advanced boundary
conditions is not in the pure heat exchanger area, but rather from recent developments in the heat and mass transfer analysis in
the emerging area of fuel cells. The comparison with conventional cases and the discussion of the significance of the advanced
boundary conditions are believed to be of key interest to the heat exchanger community as well. The correlations as function
of aspect ratio, base-angle and wall Reynolds number are included in the paper, and can be applied for design purposes.
Department/s
Publishing year
2002
Language
English
Pages
113-118
Publication/Series
Compact Heat Exchanges
Document type
Conference paper
Topic
- Energy Engineering
Conference name
Internatioanl Conference on Compact Heat Exchangers
Conference date
0001-01-02
Conference place
Grenoble, France
Status
Published