In the present study, a CFD analysis using
ANSYS-FLUENT 14.5 CFD package is used to investigate
the characteristics of heat transfer of laminar flow in annulus
formed by multi tubes in tube helically coiled heat exchanger.
The numerical results are validated by comparison with previous
experimental data and fair agreements were existed. The
influences of the design and operation parameters such as heat
flux, Reynolds numbers and annulus geometry on the heat
transfer characteristics are investigated. Different annulus of
different numbers of inner tubes, specifically 1, 2, 3, 4 and 5
tubes, are tested. The Results showed that for all the studied
annulus, the heat flux has no effect on the Nusselt number and
compactness parameter. The annulus formed by using five
inner tubes showed the best heat transfer performance and
compactness parameter. Correlation of predicting Nusselt
number in terms of Reynolds number and number of inner
tubes are presented.