This work investigated experimentally the thermal
performance of shell and coil heat exchanger with different
coil torsions (λ) for γ-Al2O3/water nanofluid flow.
Five helically coiled tube (HCT) with 0.0442 ≤ λ ≤ 0.1348
were tested within turbulent flow regime. The average size
of γ-Al2O3 particles is 40 nm and volume concentration
(ϕ) is varied from 0 to 2%. Results showed that reducing
coil torsion enhances the heat transfer rate and increases
HCT-friction factor (fc). Also, it is noticed that HCT average
Nusselt number (Nut) and fc of nanofluids increase
with increasing γ-Al2O3 volume concentration. The thermal
performance index, TPI = (ht,nf/ht,bf)/(ΔPc,nf/ΔPc,bf).
increases with increasing nanoparticles concentration, coil
torsion, HCT-side inlet temperature and nanofluid flow
rate. Over the studied range of HCT-Reynolds number,
the average value of TPI is of 1.34 and 2.24 at ϕ = 0.5%
and ϕ = 2%, respectively. The average value of TPI is of
1.64 at λ = 0.0442 while its average value at λ = 0.1348
is of 2.01. One of the main contributions is to provide heat
equipments designers with Nut and fc correlations for practical
configurations shell and coil heat exchangers with a
wide range of nanofluid concentration. |
