Heat Transfer,
Год журнала:
2023,
Номер
53(2), С. 755 - 785
Опубликована: Ноя. 22, 2023
Abstract
Heat
exchangers
have
a
wider
scope
in
numerous
applications,
such
as
space
heating,
chemical
industries,
power
stations,
and
so
on.
Due
to
heat
loss
the
thermal
properties
of
materials
involved,
overall
performance
exchanger
is
questionable.
Therefore,
studies
related
transfer
techniques
are
appreciated
research
community.
Thus,
present
study
numerically
investigates
horizontal
pipe
equipped
with
hexagonal
perforated
twisted
tape
inserts.
Further,
numerical
solutions
Nusselt
number
(
Nu
),
friction
factor
f
(TPF)
optimized
help
response
surface
methodology
(RSM).
The
parameters
investigated
this
Reynolds
Re
which
varies
between
500
1500,
input
supply
Q
)
100
1000
W,
pitch
ratio
(3.2,
4,
5.2).
ANSYS
fluid
flow
fluent
was
used
perform
simulations
for
three
different
inserts:
horizontal,
vertical,
alternate
hexagon
perforations.
Optimum
obtained
at
W
supply,
1500
,
p
/
d
i
=
4
from
alternatively
optimum
TPF
achieved
119.545,
0.437,
1.82,
respectively.
Also,
proposed
RSM
optimization
method
evidenced
maximum
2.673%
error
during
confirmatory
test.
International Journal of Thermofluids,
Год журнала:
2024,
Номер
22, С. 100689 - 100689
Опубликована: Май 1, 2024
Various
engineering
applications,
such
as
heat
exchangers,
air
conditioning
systems,
chemical
reactors,
and
refrigeration
make
use
of
enhanced
transfer
surfaces.
Numerous
methods
have
been
explored
to
improve
rates
reduce
the
size
cost
equipment
involved,
particularly
in
exchangers.
This
review
comprehensively
assesses
multiple
continuous
discrete
swirl-inducing
techniques
for
enhancing
transfer,
achieved
through
geometry
alterations
or
flow
deflectors.
The
study
showed
that
all
angles
device
effectively
promoted
fluid
mixing,
reduced
thermal
boundary
layers,
created
turbulent
eddies
due
swirl
flows
vortices.
While
solid
may
impede
local
performance
by
trapping
low-velocity
heated
fluids
within
these
move
downstream,
they
lead
improved
transport
over
large
areas.
paper
explores
application
other
specific
work
environments.
Results in Engineering,
Год журнала:
2024,
Номер
22, С. 102098 - 102098
Опубликована: Апрель 4, 2024
This
study
investigates
the
utilization
of
twisted
tapes
within
spiral
tubes,
aiming
to
fill
a
significant
research
gap.
Through
validated
numerical
simulations
using
SST
k-w
turbulence
model,
intricate
aspects
heat
transfer
and
exergy
destruction
in
spirally
coiled
tubes
with
are
explored.
Six
distinct
conditions
analyzed,
including
plain
(PST)
equipped
varying
configurations
(TTM2,
TTM3,
TTM4,
TTM5,
TTM6),
focusing
on
key
geometric
parameters
such
as
number
channels,
tape
diameter,
thickness,
pitch.
The
impact
these
critical
factors
friction
factor,
Nusselt
number,
efficiency,
thermal
performance
coefficient
is
comprehensively
evaluated.
Results
indicate
that
diameter
initially
affects
negatively
before
surpassing
tube
beyond
specific
threshold.
Optimal
thickness
pitch
improve
performance,
particularly
noticeable
at
22
mm
diameter.
Increasing
reduces
transfer,
decline
observed,
yet
all
pitched
outperform
tubes.
factor
increases
due
disproportionate
decrease
pressure
drop
versus
reduction.
Additionally,
increasing
enhances
albeit
sharper
increase
heightened
influence.
Throughout,
mathematical
model
utilized
rigorously
validated,
providing
insights
into
complex
interplay
their
effects
efficiency
tapes.
Case Studies in Thermal Engineering,
Год журнала:
2023,
Номер
53, С. 103922 - 103922
Опубликована: Дек. 17, 2023
In
this
work,
multi-criteria
decision-making
(MCDM)
techniques
namely
the
weighted
aggregated
sum
product
assessment
(WASPAS)
method
and
measuring
attractiveness
by
a
categorical
based
evaluation
technique
(MACBETH)
are
applied
for
predicting
optimum
performance
of
solar
water
heating
system
(SWHS)
equipped
with
perforated
delta-shaped
obstacles.
total
fifteen
SWHS
design
alternatives
on
variation
pitch
ratio
(0.5,
1,
1.5,
2.0),
angle
attack
(15°,
30°,
45°),
Reynolds
number
(400,
800,
1200)
were
selected.
The
Nusselt
number,
friction
factor,
thermohydraulic
efficiency
fixed
as
selection
criteria
in
evaluating
alternatives.
By
entropy
method,
importance
identified
is
quantified
weight,
whereas
ranking
determined
WASPAS
MACBETH
methods.
results
show
that
alternative
1200,
45°
exhibits
optimal
selected
criteria.
Sensitivity
analysis
was
used
to
demonstrate
robustness
acquired
findings,
which
further,
validated
using
ten
popular
models.
Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering,
Год журнала:
2024,
Номер
unknown
Опубликована: Янв. 2, 2024
A
solar
parabolic
trough
is
one
of
the
types
thermal
collector
used
to
harness
sunlight
and
convert
it
into
usable
heat
energy.
Solar
demonstrates
reduced
efficiency
compared
point-focusing
concentrating
collectors
when
comes
converting
energy
This
disparity
arises
due
its
operation
within
medium
temperature
range
100–400
°C.
The
enhancement
achievable
through
utilization
several
passive
transfer
augmentation
methods
receiver
tube.
Among
these
approaches,
implementation
conical
strip
inserts
stands
out
as
a
particularly
promising
method
in
receiver's
design
because
their
straight-forward
construction,
simple
wide
geometric
customization
options.
present
study
examines
how
performs
approaches
are
receiver.
evaluation
involved
testing
using
perforated
strips
with
pitch
ratios
(
P*)
0.5,
1.0,
1.5,
2.0,
twist
angle
φ)
6°,
8°,
10°,
12°,
geometry
θ)
60°,
70°,
80°,
90°
for
Reynolds
number
Re)
3000–21,000.
Air
working
fluid
inside
results
demonstrate
that
modified
tube
significantly
enhances
Nusselt
Nu)
friction
factor
ff)
by
4.26
7.29
times
plain
respectively.
indicates
an
improvement
characteristics
term
thermo-hydraulic
performance
([Formula:
see
text]).
maximum
text])
2.94
received
twisted
at
ratio
=
1,
6°
60°
Re
21,000.
Correlations
Nu
ff
have
also
been
established,
demonstrating
accuracy
±5.0%
±4.5%
ff.
Frontiers in Mechanical Engineering,
Год журнала:
2024,
Номер
10
Опубликована: Апрель 29, 2024
The
purpose
of
this
study
is
to
experimentally
enhance
the
heat
exchange
rate
shell
and
helical
coil
tube
exchanger
by
mixing
water
with
aluminum
oxide
(Al
2
O
3
)
nanoparticles,
as
well
explore
effect
inlet
thermal
parameters
on
performance
exchanger.
A
test
rig
was
constructed
investigate
influence
particle
concentration,
temperatures
nano-fluid.
Parameters
such
Nusselt
number,
pressure
drop,
evaluation
criteria
(PEC)
are
considered
nano-particle
In
a
wider
range
concentration
considered,
which
varies
from
0.0%–0.75%.
Experiments
without
nanoparticles
carried
out
under
identical
working
conditions.
By
analyzing
experimental
data,
it
found
that
significantly
improve
coefficient
transfer
inside
helically
coiled
tube.
From
sensitivity
analysis,
obseerved
there
slight
decrease
in
number
nano-fluid
increase
cooling
water.
Furthermore,
concluded
an
8.5%
PEC
value
observed
0.15%
0.75%.
International Journal of Heat and Technology,
Год журнала:
2024,
Номер
42(3), С. 1003 - 1010
Опубликована: Июнь 27, 2024
In
this
current
work,
heat
transfer
and
pressure
loss
are
predicted
using
a
fluid
simulation
with
incompressible
flow
inside
tube
that
has
been
equipped
twisted
tape
for
several
tested
cases.2-types
of
cutting
tests
included
in
the
set:
single
-cut
double
-cut,
different
cut
ratios
(a/b)=0.3,0.5,
0.7,
0.9.Supplied
(k-ε
model)
Ansys
Fluent,
was
run
analytically.The
were
conducted
to
test
influence
twisted-tape
on
behaivior
performance
enhancing
by
employing
water
flows
turbulent
applying
Reynold
number
measure
fluid's
velocity,
which
ranges
from
5000
25000.According
results
testing,
double-cut
case
expresses
drop
transfers
more
effectively
than
single-cut
case;
also
higher
friction
factor
values.Regarding
testing
ratio's
effect,
findings
indicate
thermalperformance
is
rising
relation
rise.There
good
agreements
found
study's
comparison
analysis
earlier
studies
same
field.
