Post on 29-Jun-2020
Contemporary Engineering Sciences, Vol. 11, 2018, no. 70, 3445 - 3462
HIKARI Ltd, www.m-hikari.com
https://doi.org/10.12988/ces.2018.87321
Heat Exchangers with Double Passive
Enhancement
Miyer Valdes
Materiales Avanzados y Energía Research Group (MATyER), Instituto
Tecnológico Metropolitano, Calle 73 No. 76A – 354, Medellín, Colombia
Juan Gonzalo Ardila Marín
Department of Mechatronics, Materiales Avanzados y Energía Research Group
(MATyER), Instituto Tecnológico Metropolitano, Calle 73 No. 76A – 354,
Medellín Colombia
Copyright © 2018 Miyer Valdes and Juan Gonzalo Ardila Marín. This article is distributed under
the Creative Commons Attribution License, which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Abstract
The use of passive enhancement for heat exchangers, as well as the interest of the
academic community in its study, has increased. It has been found that the
improvement of the transfer rate is the result of the formation of secondary flows,
the increase in turbulence or, simply, the increase in transfer area. In general terms,
when the contact between more particles and the transfer surface is enabled during
the passage through the tubes, heat transfer increases. As a result, a great deal of
studies is available, and a series of heat transfer correlations has been proposed.
Such correlations have been numerically or experimentally developed, and enable
to predict the convection and estimate the size of the exchangers, which makes them
a fundamental design tool. This article is a review of the most important studies
recently published in this field. It presents the geometries that provide single and
double passive enhancements and some of the correlations that are applied to heat
exchangers with double passive enhancement. In brief, this work constitutes a
thorough review of the results of numerical and/or experimental research—as well
as other reviews—in the field of heat exchangers in which the transfer phenomenon
has been improved by means of passive techniques.
Keywords: Heat transfer, Nusselt number, Dean number, Curved tube, Insert
3446 Miyer Valdes and Juan Gonzalo Ardila Marín
1 Introduction
Heat exchangers are devices used to transfer heat from one fluid to another
without mixing them. They are fundamental in many industrial applications such as
refrigeration, heating, air conditioning, agricultural production and vapor
generation systems, as well as cogeneration and chemical plants, among others [1].
The simplest type of exchanger is composed of two tube-in-tubes of different
diameters; this is called a double pipe exchanger. Probably, the most common type
in industrial applications is the shell and tube heat exchanger. These exchangers
contain a great number of tubes parallelly bundled inside a shell [2]. Enhancing the
performance of the exchangers is very important because it is related to energy
saving [1]. For this purpose, two main types of technique have been developed:
active and passive. The first requires external power, such as vibration or magnetic
fields; the second uses inserts or deformations in the surface of the tubing and no
external energy [3]. The passive technique with tube curving has been the most
widely used due to its compact size and high heat transfer coefficient produced by
the pattern of secondary flows studied by Dean since 1927 [4]. In turn, the single
enhancement techniques involve inserting springs, twisted and staggered tapes in
straight tubes, as well as corrugating or curving the latter [1], [5], [6]. Another
technique is the double improvement, i.e. a combination of two simple
enhancements [7] such as a curved tube with spring inserts, corrugation or baffles,
or a straight corrugated tube with tape inserts [8]–[11]. Passive enhancement is the
preferred technique and different geometries have been developed to increase heat
transfer. The following is a general overview of heat exchangers with passive
enhancement reported in the literature. The first section is a description of the
geometries of tubes with simple and double enhancements. Afterwards, the authors
that have conducted CFD studies of double enhancement exchangers are
mentioned. Subsequently, a table lists the heat transfer correlations of double
enhancements found by different authors. Finally, the heat transfer performance of
tubes with double enhancement is described.
2 Geometries of exchangers with simple passive enhancement
The use of an enhancement technique can be restricted to a specific application.
For example, corrugated and dimpled tubes are applicable in the food industry, but
inserts are not due to hygiene issues. In the petrochemical industry, the use of
mechanically bent tubes is not allowed for safety reasons. However, the use of
inserts does not pose any problem. In boilers and heat recovery systems, inserts are
often used because they are easily extracted for cleaning operations [6]. The
performance of many conventional heat exchange systems is generally poor due to
the development of the thermal boundary layer, which results in a low coefficient
of heat transfer by convection between the fluid and the hot surface. A thinner
boundary layer is needed on the heated surface to enhance heat transfer by
convection and reduce overall thermal resistance [12]. The heat transfer coefficient
in a turbulent flow is increased by mixing the flow at the boundary layer and by
Heat exchangers with double passive enhancement 3447
raising the level of turbulence of the flow [13]. In order to obtain such increases,
the surface of the tube is deformed or inserts are added. Skullong et al. studied
several inserts of staggered-winglet perforated tape and compared them to inserts
of non-perforated tape. Both types of tape maintained the same ratios of staggering
height and pitch to tube diameter, and the ratio of perforation area to total area was
equivalent to the porosity ratio of the insert [12] (Figure 1a). Li et al. studied three
combinations of twisted tape inserts: a tape the width of the tube; an internal tube
along with an insert; and an internal tube and four inserts. All these tapes had the
same tape pitch to width ratio [1] (Figure 1b).
Figure 1. Tape inserts. a) Staggered-winglet tape insert, adapted from [12]. b)
Twisted tape insert, adapted from [1].
Liu et al. compared smooth straight tubes and straight tubes with wire coil inserts
in a shell heat exchanger; the tube diameters were the same in both cases [14]
(Figure 2a). García et al. compared three tubes: smooth with wire coil insert,
corrugated and dimpled [6] (Figure 2b). Vicente et al. studied corrugated tubes with
different geometrical parameters by varying the corrugation depth and pitch and
maintaining the same tube diameter [13] (Figure 2c). Vulchanov and Zimparov
studied straight tubes with sand-type roughness with different ratios of roughness
depth to tube diameter and roughness depth to tube length [15].
3448 Miyer Valdes and Juan Gonzalo Ardila Marín
Figure 2. Straight tubes with helical modifications. a) Wire coil insert, adapted
from [14]. b) Wire coil insert and dimpled tube, adapted from [6]. c) Corrugated
tube, adapted from [13].
Besides the enhancements presented above, the helically coiled exchanger has been
widely reported in the literature due to its high rate of heat transfer compared to
straight tubes—which is the result of its compact structure—and high heat transfer
coefficient [16], [17]. The most outstanding feature of the flow in helically coiled
exchangers is the secondary flow induced by centrifugal force—caused by the
curvature of the tubing—that pushes the particles of fluid towards the central region
and produces a secondary flow field that improves heat transfer [5], [18], [19]. As
a consequence, the heat transfer and friction factor of this type of exchangers are
significantly higher than straight tubing [20]–[22]. Based on the assumption of
smooth curves and low velocities, Dean raised the Navier-Stokes equations in
cylindrical coordinates and proposed a series of solutions for the secondary flow
function and for the axial velocity, from which arose the parameter known by its
name: Dean's number (De), which relates the centrifugal and inertial effects [23].
The following authors have studied helically coiled heat exchangers. Di Piazza and
Ciofalo compared a helically coiled tube with a straight tube, both of the same
length [24]. Kurnia et al. studied three configurations of tubes with square cross-
sections [5] (Figure 3) and compared them with a straight tube with identical cross-
section and length. Conté and Peng studied an internally and externally coiled tube
with a rectangular and curved pattern [25], as shown in Figure 4.
Heat exchangers with double passive enhancement 3449
Figure 3. Configurations of tubes with square cross-section. a) Straight b) Conical
c) Helical d) In-plane, adapted from [5].
Figure 4. Coiled tube with rectangular pattern, adapted from [25].
The most exhaustively studied geometry is helically coiled tubes. There are many
types of configurations for this geometry, such as the one proposed by Zhao et al.,
who investigated a coiled tube with membrane [26] (Figure 5a). Different experts
have studied helically coiled tubes placed inside a storage tank [27]–[36] (Figure
5b). Rennie and Raghavan, as well as Zachár, studied a tube-in-tube helical heat
exchanger [18], [22] (Figure 5c).
3450 Miyer Valdes and Juan Gonzalo Ardila Marín
Figure 5. Helically coiled tube. a) Tube with membrane, adapted from [26]. b)
Tube in storage tank, adapted from [19]. c) Tube-in-tube, adapted from [22].
3 Geometries of exchangers with double passive enhancement
Besides simple passive enhancement, there is double enhancement, i.e. the
combination of two simple improvements. The simultaneous use of two
enhancements has been researched by several authors. Bhattacharyya and Saha
studied a tube with integral helical rib roughness and a center-cleared twisted-tape
insert [37] (Figure 6a). Promvonge experimented with wire coil and twisted tape
placed inside it [10] (Figure 6b). Zimparov studied a helically corrugated tube with
twisted inserts [38]–[41] (Figure 6c). Wongcharee and S. Eiamsa-ard compared two
twisted insert arrangements, parallel and counter arrangements, relative to the
direction of the helical corrugation of the tube [42] (Figure 6d).
Ardila and Hincapié studied heat exchangers with double enhancement: curved and
twisted tubes [43], [44]. Khairul et al. experimented with a helically coiled heat
exchanger with helical corrugation as well [45]. Kumar et al. studied a tube-in-tube
helical exchanger with semi-circular baffles to provide turbulence and maintain the
curvature of the tubes [46] (Figure 7a). Mozafari et al., as well as Wongwises and
Polsongkram, experimented with tube-in-tube configurations and triangular
supports between the tubes, which induced a second passive enhancement [9], [47],
[48] (Figure 7b). Yildiz et al. studied a helically coiled tube with a wire coil insert
Heat exchangers with double passive enhancement 3451
[49]. Rainieri et al. compared a straight helically corrugated tube to a helical
corrugated tube with the same type of corrugation [3], [7] (Figure 8a). Li et al. and
Zachár analyzed a helically coiled tube with two-turn helical corrugation [8], [11]
(Figure 8b). Ardila et al. made a comparison between helical smooth tube-in-tubes
and helical corrugated tubes of one and four inlets [50] (Figure 8c).
Figure 6. Double enhancement in straight tubes. a) Tube with integral helical rib
roughness and center-cleared twisted tape insert, adapted from [37]. b) Tube with
wire coil and tape, adapted from [10]. c) Helically corrugated tube with twisted
inserts, adapted from [40]. d) Twisted inserts in parallel and counter arrangement
relative to the direction of the helical corrugation, adapted from [42].
3452 Miyer Valdes and Juan Gonzalo Ardila Marín
Figure 7. Helically coiled tubes. a) Tube-in-tube with semi-circular baffles,
adapted from [46]. b) Helical tube-in-tube with triangular supports, adapted from
[47].
Heat exchangers with double passive enhancement 3453
Figure 8. Helically coiled tubes. a) Helically corrugated helical tube, adapted from
[7]. b) Two-turn helical corrugation, adapted from [8]. c) One- and four-inlet
helical tubes, adapted from [51].
4 CFD studies
Computational Fluid Dynamics (CFD) is a branch of fluid mechanics that uses
numerical methods, such as finite volume, to analyze phenomena of the fluids [50].
CFD programs enable to predict numerical results approximated to experimental
results. This validation has been widely reported in the literature [46]. The accuracy
of the results depends on the configuration of the simulation that adopts turbulence
models such as k-ε, k-ω, DNS, RSM, SST and algorithms like IMPLE, SIMPLEC,
PISO, etc. Some Italian researchers studied the incidence of turbulence models in
the results of simulations and reported that the RSM-ω model—for turbulent flows
greater than 14,000 Reynolds—yields excellent results compared to the
experiments [23]. Wang et al. concluded that the SST model provides the best
prediction of the experimental heat transfer coefficient, and the maximum error
between experimental data and the predictions of such model are in the 10% range
[36]. Besides, Jayakumar et al., as well as Rennie and Raghavan, numerically
studied the effects of the thermo-dependent properties of the fluid in heat
exchangers [17], [18]. Other authors found that the predictions of the CFD
reasonably match the experimental results [17], [20], [31], [35]. Additionally,
Jayakumar et al. confirmed that the CFD predictions matched the experimental
results within experimental error limits of 5% [17]. Kumar et al. concluded that the
numerical predictions for hydrodynamics and fully developed heat transfer were in
good agreement with the experimental results, with an error between 4% and 10%
[46].
3454 Miyer Valdes and Juan Gonzalo Ardila Marín
5 Heat transfer correlations
Several authors have reported heat transfer correlations resulting from their
experimental and numerical studies. The nature of the correlations available in the
literature (Table 1) suggests that they are defined in terms of the Nusselt number
(Nu), as shown in Equation (1). This number provides a measurement of heat
transfer by convection. It is defined as a function of the Reynolds number,
represented by Equation (2), that establishes the relationship between inertial and
viscous forces in the flow and determines if the flow is turbulent or laminar based
on certain critical values. Sometimes, Re is replaced by the Dean number (De)
defined in Equation (3), which results from the product of Re and the square root
of the quotient of characteristic radii of a curved exchanger. The other typical
parameter, as a function of which Nu is correlated, is the Prandtl number in
Equation (4). Such number is the ratio of momentum diffusivity to thermal
diffusivity, a characteristic of the fluid that provides a measurement of the relative
effectivity of momentum and energy transfer by diffusion at thermal and
hydrodynamic boundary layers [44].
Pr,Defk
hDNu
f
(1)
Where h is the heat transfer coefficient; D , the hydraulic diameter of the
exchanger; and fk , the thermal conductivity of the fluid.
VDRe
(2)
Where is the fluid density; V the mean fluid velocity; and , the dynamic
viscosity of the fluid.
R
rDe Re
(3)
Where r is the hydraulic radius of the tube and R is the radius of the helix
curvature.
f
p
k
c Pr
(4)
Where pc is heat capacity.
Heat exchangers with double passive enhancement 3455
Table 1. Correlations by different authors
Correlation Author 4.09112.0 Pr025.0 DeNu (5) [17]
For a straight tube with wire coil inserts 281.0Re012.0Nu (6)
[14] For a straight smooth tube
634.0Re0003.0Nu (7)
R
rNu 455.31PrRe00619.0 4.092.0
(8) [23]
22.04.077.0 1PrRe0061.0 Nu (9)
Where is nanofluid concentration.
[32]
192.0166.0
408.06688.0 Pr5855.0
D
p
D
hDeNu (10)
Where h is corrugation depth and p
is the helical pitch of the corrugation
[11]
Factorial design 3.050096.001646.0 Pr
1083514.2 s
DeVaNuosc
(11)
Where oscNu is the average oscillatory Nusselt and Va is the Valensi number.
2
2*2 rf
Where is the kinematic viscosity and f is the frequency
[4]
Uniform design 3.0
56388.0
01441.0 Pr10
03593.2
DeVaNuosc (12)
4.087.0 Pr280Re012.0 Nu (13) [41]
0238.0132.04055.5432.0 10*Pr98.6895 ttEqtp BoDeNu (14)
Where tpNu
is the two-phase Nusselt; eqDe
, the equivalent Dean; Bo , the
boiling number; and tt, the Martinelli parameter
[48]
44.074.025.0
2
Pr1500Re*
374.0
DphNu (15) [13]
Smooth tube 16.047.0 Pr1168.0 DeNu (16)
Corrugated tube 2.036.1 Pr0919.0 DeNu (17)
[3]
28.02.0 Pr08.2 DeNu for 100Pr18212 De (18)
[18]
46.058.0 Pr39.0 DeNu for 500Pr100212 De (19)
29.03.0 Pr7.2 DeNu for 4.0,2315Pr500212 DDe (20)
19.02.0 Pr27.5 DeNu for 6.0,1610Pr500212 DDe (21)
3456 Miyer Valdes and Juan Gonzalo Ardila Marín
Table 1. (Continued): Correlations by different authors
38.0382.04.05.0 PrRe47.4 YCRNu (22)
Where CR is the ratio of the wire coil pitch dN and Y is the torsion ratio
wH
Where N is the wire coil pitch; d , the thickness of the wire coil; and w , the
thickness of the twisted tape.
[10]
Perforated tape 2536.03097.04.07682.0 PrPrRe1844.0 BrNu (23)
Where Br is the winglet blockage ratio Db
Where b is the thickness of the winglet.
Non-perforated tape 1714.04.07689.0 PrRe1949.0 BrNu (24)
[12]
4.08291.0Pr0506.0 DeNu (25) [31]
096856199.03.0834694285.0 PrRe02652604.0
MNu (26)
Where M is the gap ratio Dpp ie
Where ep is the pitch of the external helical diameter and ip is the pitch of the
internal helical diameter.
[27]
112.043356.00432.08144.07654.0 10*PrPr1352.0 BoDeNu ttlEqtp
(27)
Where lPr is the Prandtl number of the liquid.
[47]
6 Heat transfer
The following heat transfer results have been published regarding heat exchangers
with double passive enhancement: Mozafari et al. indicated that the average heat
transfer coefficient of a helical tube-in-tube is between 24% and 165%, greater than
that of a straight tube [9]. Rainieri et al. reported that a helical tube with corrugation
increases heat transfer up to 25 times, in contrast with a friction factor increase of
2.5 [3]. Rainieri et al. found that—for Re=1,000—helical corrugated tubes present
a Nusselt number 7 times higher than smooth straight tubes [7]. Wongwises and
Polsongkram found heat transfer with evaporation in a helical tube-in-tube presents
30 to 37% better performance than in a straight tube-in-tube [48]. They also found
that the coefficient of heat transfer with condensation in a helical tube-in-tube is
higher—33 to 53%—than in a straight tube [47]. Finally, Zachár concluded that the
heat transfer rate increases 100% more in a helical tube with helical corrugation
than in a smooth helical tube, both in a De number range from 30 to 1,400 [11].
7 Conclusions
This work reports a thorough review of the results of numerical and/or
experimental research—as well as other reviews—in the field of heat exchangers in which the transfer phenomenon has been improved by means of passive techniques.
Heat exchangers with double passive enhancement 3457
Two types of research are differentiated: (1) studies conducted with exchangers
with simple enhancement provided by inserts—generally wires or tapes, in which
helical deformation is common—as well as curving or deforming the tubes or their
surfaces with metalwork and (2) studies conducted on heat exchangers with a
combination of two previously mentioned enhancements—i.e. double inserts or an
insert in addition to tube deformation. All the studies show the expected
enhancement effect after applying the technique. Such improvements vary with the
degree of deformation of the tube or insert, due to the increase in turbulence of the
fluids that results in greater contact of the particles with the transfer surfaces.
Besides, the formation of secondary flows is evaluated. The latter has been studied
by Dean since 1930 and it is associated with centrifugal forces caused by the
curvature of the tubes in the exchangers. Furthermore, many studies confirm that
the combination of passive techniques increases the improvement effect compared
to simple enhancement and to the traditional arrangement of straight smooth tubes.
Additionally, a complete collection of heat transfer correlations was presented in
terms of the Nusselt number given as a function of other dimensionless parameters
that characterize the flow based on features such as velocity, geometry (diameters,
lengths and curvature radii) and the fluid properties (most of them thermo-
dependent, such as density, viscosity, thermal conductivity and specific heat).
These correlations enable project engineers to establish the size of devices for
industrial applications and are useful to promote of the use of this technology that
increases energy recovery and plant efficiency.
References
[1] P. Li, Z. Liu, W. Liu and G. Chen, Numerical study on heat transfer
enhancement characteristics of tube inserted with centrally hollow narrow
twisted tapes, Int. J. Heat Mass Transfer, 88 (2015), 481–491.
https://doi.org/10.1016/j.ijheatmasstransfer.2015.04.103
[2] Y. A. Cengel, Transferencia de Calor y Masa, Tercera Ed. México D.F.:
Mcgraw-Hill/Interamericana Editores, S.A. DE C.V, 2007.
[3] S. Rainieri, F. Bozzoli, L. Cattani and G. Pagliarini, Compound convective
heat transfer enhancement in helically coiled wall corrugated tubes, Int. J.
Heat Mass Transfer, 59 (2013), 353–362.
https://doi.org/10.1016/j.ijheatmasstransfer.2012.12.037
[4] C. Pan, Y. Zhou and J. Wang, CFD study of heat transfer for oscillating flow
in helically coiled tube heat-exchanger, Comput. Chem. Eng., 69 (2014), 59–
65. https://doi.org/10.1016/j.compchemeng.2014.07.001
[5] J. C. Kurnia, A. P. Sasmito, S. Akhtar, T. Shamim and A. S. Mujumdar,
Numerical Investigation of Heat Transfer Performance of Various Coiled
3458 Miyer Valdes and Juan Gonzalo Ardila Marín
Square Tubes for Heat Exchanger Application, Energy Procedia, 75 (2015),
3168–3173. https://doi.org/10.1016/j.egypro.2015.07.655
[6] A. García, J. P. Solano, P. G. Vicente and A. Viedma, The influence of
artificial roughness shape on heat transfer enhancement: Corrugated tubes,
dimpled tubes and wire coils, Appl. Therm. Eng., 35 (2012), 196–201.
https://doi.org/10.1016/j.applthermaleng.2011.10.030
[7] S. Rainieri, F. Bozzoli and G. Pagliarini, Experimental investigation on the
convective heat transfer in straight and coiled corrugated tubes for highly
viscous fluids: Preliminary results, Int. J. Heat Mass Transfer, 55 (2012), no.
1–3, 498–504. https://doi.org/10.1016/j.ijheatmasstransfer.2011.08.030
[8] Y. Li, J. Wu, H. Wang, L. Kou and X. Tian, Fluid Flow and Heat Transfer
Characteristics in Helical Tubes Cooperating with Spiral Corrugation, Energy
Procedia, 17 (2012), 791–800. https://doi.org/10.1016/j.egypro.2012.02.172
[9] M. Mozafari, M. A. Akhavan-Behabadi, H. Qobadi-Arfaee and M. Fakoor-
Pakdaman, Condensation and pressure drop characteristics of R600a in a
helical tube-in-tube heat exchanger at different inclination angles, Appl.
Therm. Eng., 90 (2015), 571–578.
https://doi.org/10.1016/j.applthermaleng.2015.07.044
[10] P. Promvonge, Thermal augmentation in circular tube with twisted tape and
wire coil turbulators, Energy Convers. Manag., 49 (2008), no. 11, 2949–2955.
https://doi.org/10.1016/j.enconman.2008.06.022
[11] A. Zachár, Analysis of coiled-tube heat exchangers to improve heat transfer
rate with spirally corrugated wall, Int. J. Heat Mass Transfer, 53 (2010), no.
19–20, 3928–3939. https://doi.org/10.1016/j.ijheatmasstransfer.2010.05.011
[12] S. Skullong, P. Promvonge, C. Thianpong and M. Pimsarn, Heat transfer and
turbulent flow friction in a round tube with staggered-winglet perforated-tapes,
Int. J. Heat Mass Transfer, 95 (2016), 230–242.
https://doi.org/10.1016/j.ijheatmasstransfer.2015.12.007
[13] P. G. Vicente, A. Garcı́a, and A. Viedma, Experimental investigation on heat
transfer and frictional characteristics of spirally corrugated tubes in turbulent
flow at different Prandtl numbers, Int. J. Heat Mass Transfer, 47 (2004), no.
4, 671–681. https://doi.org/10.1016/j.ijheatmasstransfer.2003.08.005
[14] L. Liu, X. Ling and H. Peng, Analysis on flow and heat transfer characteristics
of EGR helical baffled cooler with spiral corrugated tubes, Exp. Therm. Fluid
Sci., 44 (2013), 275–284.
https://doi.org/10.1016/j.expthermflusci.2012.06.019
Heat exchangers with double passive enhancement 3459
[15] N. L. Vulchanov and V. D. Zimparov, Stabilized turbulent fluid friction and
heat transfer in circular tubes with internal sand type roughness at moderate
Prandtl numbers, Int. J. Heat Mass Transfer, 32 (1989), no. 1, 29–34.
https://doi.org/10.1016/0017-9310(89)90088-4
[16] J. S. Jayakumar, S. M. Mahajani, J. C. Mandal, K. N. Iyer and P. K. Vijayan,
Thermal hydraulic characteristics of air–water two-phase flows in helical
pipes, Chem. Eng. Res. Des., 88 (2010), no. 4, 501–512.
https://doi.org/10.1016/j.cherd.2009.09.007
[17] J. S. Jayakumar, S. M. Mahajani, J. C. Mandal, P. K. Vijayan and R. Bhoi,
Experimental and CFD estimation of heat transfer in helically coiled heat
exchangers, Chem. Eng. Res. Des., 86 (2008), no. 3, 221–232.
https://doi.org/10.1016/j.cherd.2007.10.021
[18] T. J. Rennie and V. G. S. Raghavan, Effect of fluid thermal properties on the
heat transfer characteristics in a double-pipe helical heat exchanger, Int. J.
Therm. Sci., 45 (2006), no. 12, 1158–1165.
https://doi.org/10.1016/j.ijthermalsci.2006.02.004
[19] A. Zachár, Investigation of natural convection induced outer side heat transfer
rate of coiled-tube heat exchangers, Int. J. Heat Mass Transfer, 55 (2012), no.
25–26, 7892–7901. https://doi.org/10.1016/j.ijheatmasstransfer.2012.08.014
[20] M. Colombo, A. Cammi, G. R. Guédon, F. Inzoli and M. E. Ricotti, CFD study
of an air–water flow inside helically coiled pipes, Prog. Nucl. Energy, 85
(2015), 462–472. https://doi.org/10.1016/j.pnucene.2015.07.006
[21] G. Huminic and A. Huminic, Heat transfer and entropy generation analyses of
nanofluids in helically coiled tube-in-tube heat exchangers, Int. Commun. Heat
Mass Transfer, 71 (2016), 118–125.
https://doi.org/10.1016/j.icheatmasstransfer.2015.12.031
[22] A. Zachár, Investigation of a new tube-in-tube helical flow distributor design
to improve temperature stratification inside hot water storage tanks operated
with coiled-tube heat exchangers, Int. J. Heat Mass Transfer, 63 (2013), 150–
161. https://doi.org/10.1016/j.ijheatmasstransfer.2013.03.055
[23] I. Di Piazza and M. Ciofalo, Numerical prediction of turbulent flow and heat
transfer in helically coiled pipes, Int. J. Therm. Sci., 49 (2010), no. 4, 653–663.
https://doi.org/10.1016/j.ijthermalsci.2009.10.001
[24] D. G. Prabhanjan, G. S. V. Raghavan and T. J. Rennie, Comparison of heat
transfer rates between a straight tube heat exchanger and a helically coiled heat
exchanger, Int. Commun. Heat Mass Transfer, 29 (2002), no. 2, 185–191.
3460 Miyer Valdes and Juan Gonzalo Ardila Marín
https://doi.org/10.1016/s0735-1933(02)00309-3
[25] I. Conté and X. F. Peng, Numerical and experimental investigations of heat
transfer performance of rectangular coil heat exchangers, Appl. Therm. Eng.,
29 (2009), no. 8–9, 1799–1808.
https://doi.org/10.1016/j.applthermaleng.2008.08.013
[26] Z. Zhao, X. Wang, D. Che and Z. Cao, Numerical studies on flow and heat
transfer in membrane helical-coil heat exchanger and membrane serpentine-
tube heat exchanger, Int. Commun. Heat Mass Transfer, 38 (2011), no. 9,
1189–1194. https://doi.org/10.1016/j.icheatmasstransfer.2011.06.014
[27] R. Kharat, N. Bhardwaj and R. S. Jha, Development of heat transfer coefficient
correlation for concentric helical coil heat exchanger, Int. J. Therm. Sci., 48
(2009), no. 12, 2300–2308.
https://doi.org/10.1016/j.ijthermalsci.2009.04.008
[28] C. X. Lin and M. A. Ebadian, The effects of inlet turbulence on the
development of fluid flow and heat transfer in a helically coiled pipe, Int. J.
Heat Mass Transfer, 42 (1999), no. 4, 739–751.
https://doi.org/10.1016/s0017-9310(98)00193-8
[29] W. C. Lin, Y. M. Ferng and C. C. Chieng, Numerical computations on flow
and heat transfer characteristics of a helically coiled heat exchanger using
different turbulence models, Nucl. Eng. Des., 263 (2013), 77–86.
https://doi.org/10.1016/j.nucengdes.2013.03.051
[30] S. Mirfendereski, A. Abbassi and M. Saffar-Avval, Experimental and
numerical investigation of nanofluid heat transfer in helically coiled tubes at
constant wall heat flux, Adv. Powder Technology, 26 (2015), no. 5, 1483–
1494. https://doi.org/10.1016/j.apt.2015.08.006
[31] S. S. Pawar and V. K. Sunnapwar, Experimental and CFD investigation of
convective heat transfer in helically coiled tube heat exchanger, Chem. Eng.
Res. Des., 92 (2014), no. 11, 2294–2312.
https://doi.org/10.1016/j.cherd.2014.01.016
[32] M. Rakhsha, F. Akbaridoust, A. Abbassi and S.-A. Majid, Experimental and
numerical investigations of turbulent forced convection flow of nano-fluid in
helical coiled tubes at constant surface temperature, Powder Technol., 283
(2015), 178–189. https://doi.org/10.1016/j.powtec.2015.05.019
[33] S. Vashisth and K. D. P. Nigam, Prediction of flow profiles and interfacial
phenomena for two-phase flow in coiled tubes, Chem. Eng. Process. Process
Heat exchangers with double passive enhancement 3461
Intensif., 48 (2009), no. 1, 452–463.
https://doi.org/10.1016/j.cep.2008.06.006
[34] M. Visaria and I. Mudawar, Coiled-tube heat exchanger for High-Pressure
Metal Hydride hydrogen storage systems – Part 1. Experimental study, Int. J.
Heat Mass Transfer, 55 (2012), no. 5–6, 1782–1795.
https://doi.org/10.1016/j.ijheatmasstransfer.2011.11.035
[35] M. Visaria and I. Mudawar, Coiled-tube heat exchanger for high-pressure
metal hydride hydrogen storage systems – Part 2. Computational model, Int.
J. Heat Mass Transfer, 55 (2012), no. 5–6, 1796–1806.
https://doi.org/10.1016/j.ijheatmasstransfer.2011.11.036
[36] K. Wang, X. Xu, Y. Wu, C. Liu and C. Dang, Numerical investigation on heat
transfer of supercritical CO2 in heated helically coiled tubes, J. Supercrit.
Fluids, 99 (2015), 112–120. https://doi.org/10.1016/j.supflu.2015.02.001
[37] S. Bhattacharyya and S. K. Saha, Thermohydraulics of laminar flow through
a circular tube having integral helical rib roughness and fitted with centre-
cleared twisted-tape, Exp. Therm. Fluid Sci., 42 (2012), 154–162.
https://doi.org/10.1016/j.expthermflusci.2012.05.002
[38] V. Zimparov, Enhancement of heat transfer by a combination of a single-start
spirally corrugated tubes with a twisted tape, Exp. Therm. Fluid Sci., 25
(2002), no. 7, 535–546. https://doi.org/10.1016/s0894-1777(01)00112-1
[39] V. Zimparov, Prediction of friction factors and heat transfer coefficients for
turbulent flow in corrugated tubes combined with twisted tape inserts. Part 2:
heat transfer coefficients, Int. J. Heat Mass Transfer, 47 (2004), no. 2, 385–
393. https://doi.org/10.1016/j.ijheatmasstransfer.2003.08.004
[40] V. Zimparov, Prediction of friction factors and heat transfer coefficients for
turbulent flow in corrugated tubes combined with twisted tape inserts. Part 1:
friction factors, Int. J. Heat Mass Transfer, 47 (2004), no. 3, 589–599.
https://doi.org/10.1016/j.ijheatmasstransfer.2003.08.003
[41] V. Zimparov, Enhancement of heat transfer by a combination of three-start
spirally corrugated tubes with a twisted tape, Int. J. Heat Mass Transfer, 44
(2001), no. 3, 551–574. https://doi.org/10.1016/s0017-9310(00)00126-5
[42] K. Wongcharee and S. Eiamsa-ard, Heat transfer enhancement by using
CuO/water nanofluid in corrugated tube equipped with twisted tape, Int.
Commun. Heat Mass Transfer, 39 (2012), no. 2, 251–257.
https://doi.org/10.1016/j.icheatmasstransfer.2011.11.010
3462 Miyer Valdes and Juan Gonzalo Ardila Marín
[43] J. Ardila and D. Hincapié, Modelado Geométrico de Intercambiadores de
Calor de Tubo en Espiral Helicoidal Torsionado, Rev. Politécnica, 2351
(2014), 55–64.
[44] J. Ardila and D. Hincapie, Spiral Tube Heat Exchanger, UIS Ing., no. 2, 1–2,
2012.
[45] M. A. Khairul, A. Hossain, R. Saidur and M. A. Alim, Prediction of heat
transfer performance of CuO/water nanofluids flow in spirally corrugated
helically coiled heat exchanger using fuzzy logic technique, Comput. Fluids,
100 (2014), 123–129. https://doi.org/10.1016/j.compfluid.2014.05.007
[46] V. Kumar, S. Saini, M. Sharma and K. D. P. Nigam, Pressure drop and heat
transfer study in tube-in-tube helical heat exchanger, Chem. Eng. Sci., 61
(2006), no. 13, 4403–4416. https://doi.org/10.1016/j.ces.2006.01.039
[47] S. Wongwises and M. Polsongkram, Condensation heat transfer and pressure
drop of HFC-134a in a helically coiled concentric tube-in-tube heat exchanger,
Int. J. Heat Mass Transfer, 49 (2006), no. 23–24, 4386–4398.
https://doi.org/10.1016/j.ijheatmasstransfer.2006.05.010
[48] S. Wongwises and M. Polsongkram, Evaporation heat transfer and pressure
drop of HFC-134a in a helically coiled concentric tube-in-tube heat exchanger,
Int. J. Heat Mass Transfer, 49 (2006), no. 3–4, 658–670.
https://doi.org/10.1016/j.ijheatmasstransfer.2005.08.017
[49] C. Yildiz, Y. Biçer and D. Pehlivan, Heat transfer and pressure drop in a heat
exchanger with a helical pipe containing inside springs, Energy Convers.
Manag., 38 (1997), no. 6, 619–624.
https://doi.org/10.1016/s0196-8904(96)00040-4
[50] J. Ardila, D. Hincapié and J. Casas, Numerical models validation to
correlations development for heat exchangers, Actas Ing., 1 (2015), 164–168.
[51] J. Ardila, D. Hincapié and J. Casas, Comparison and validation of turbulence
models in the numerical study of heat exchangers,TECCIENCIA, 10 (2015),
no. 19, 49–60. https://doi.org/10.18180/tecciencia.2015.19.8
Received: July 30, 2018; Published: August 30, 2018