Dipak Sen and Rajdeep Ghosh
A Computational Study of Very High Turbulent Flow and Heat Transfer Characteristics in Circular Duct with Hemispherical Inline Baffles
1046 - 1051
2015
9
6
International Journal of Mechanical and Mechatronics Engineering
https://publications.waset.org/pdf/10001772
https://publications.waset.org/vol/102
World Academy of Science, Engineering and Technology
This paper presents a computational study of steady
state three dimensional very high turbulent flow and heat transfer
characteristics in a constant temperaturesurfaced circular duct fitted
with 900 hemispherical inline baffles. The computations are based on
realizable k model with standard wall function considering the
finite volume method, and the SIMPLE algorithm has been
implemented. Computational Study are carried out for Reynolds
number, Re ranging from 80000 to 120000, Prandtl Number, Pr of
0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of
the channel, hydrodynamic entry length, thermal entry length and the
test section. Ansys Fluent 15.0 software has been used to solve the
flow field. Study reveals that circular pipe having baffles has a higher
Nusselt number and friction factor compared to the smooth circular
pipe without baffles. Maximum Nusselt number and friction factor
are obtained for the PR5 and PR1 respectively. Nusselt number
increases while pitch ratio increases in the range of study; however,
friction factor also decreases up to PR 3 and after which it becomes
almost constant up to PR 5. Thermal enhancement factor increases
with increasing pitch ratio but with slightly decreasing Reynolds
number in the range of study and becomes almost constant at higher
Reynolds number. The computational results reveal that optimum
thermal enhancement factor of 900 inline hemispherical baffle is
about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows
that the optimum pitch ratio for which the baffles can be installed in
such very high turbulent flows should be 5. Results show that pitch
ratio and Reynolds number play an important role on both fluid flow
and heat transfer characteristics.
Open Science Index 102, 2015