Intensification of performance of pipe with nanoparticle flow along turbulator with obstacles
Graphical abstract
Introduction
Passive methods are employed to increase heat transfer rate so that the new designed system obtains the minimum size considering the limitation of pressure fall. To obtain any of the mentioned targets, numerous heat transfer increment methods showing various benefits in views of friction and heat transfer efficiency [1]. The growth of convective rate can be obtained in many paths such as using nanomaterial as a testing fluid, turbulator to grow the local turbulence, extended surface installed to the internal side of the pipe to raise the area. The most favorable property of a turbulence promoter is known by its maximum Nu and the its lowest growth of pressure fall. Many kinds of nano-powders such as nanotubes, ceramics and metals have been analyzed to increase the heat conductivity of testing fluid [2]. Some techniques to increase heat transfer performance such as suspending nano-powders into typical fluid and employing instruments in the pipe were presented by Ahmad et al. [3]. An alternative method for choosing the highest appropriate turbulence promoter for increasing the heat transfer rate in tubular system was proposed by Picón-Núñez and Melo-González [4]. Their outcomes showed that the greatest thermal performance belong the V-cut TT, the straight tape including center wings and the square-cut twisted tape. The heat transfer efficiency of TiO2 nanomaterial in a pipe was scrutinized by Bhanvase et al. [5]. The researchers observed 105 percent increment in heat transfer rate at the Re=1500 for 0.5 vol% nanomaterial. Effect of TT on heat transfer rate of nanomaterial inside a circular channel has been scrutinized by Sundar and Sharma [6]. The authors observed that the Nu increase up to 33.5 percent by applying alumina oxide/H2O nanomaterial as the operant liquid in their analysis.
Eiamsa-ard and Kiatkittipong [7] analyzed the efficiency of multiple TT, titanium oxide/H2O within a tube and observed that the maximum thermal efficiency was 1.59 where Darcy factor and Nu grew to 11.7 times and 3.52 times of those in the smooth instance with the basis fluid. The use of nanomaterial inside heat exchangers was summarized by Olabi et al. [8]. The researchers stated that the existence of the nanomaterial increases the heat transfer rate. CNT nanomaterial applying double distilled water and combined surfactant with the ratio of 1 was provided by Singh et al. [9]. The authors observed that the friction coefficient was grown with the growth in Re. Nu was 62 percent greater for CNT nanomaterial at Re=5000 in comparison to H2O. Gkountas et al. [10] analyzed PCHE applied as pre-cooler for Brayton cycle and using alumina oxide/H2O nanomaterial is presented. Based on their results, the maximum utilized nano-powder concentration of 5 percent leads to an increase of 75 percent for Nu and a decrease 8 percent in pressure fall. Liu et al. [11] defined a principle for convective flow and introduced factor for accessible work, and an equation of local exergy destruction has been defined. Empirically, Singh and Sarkar [12] analyzed the effect of applying V-cuts TT insert and PCM suspended hybrid or mono nanomaterial on the hydrothermal features of the double pipe. Results demonstrated that the Δp and the heat transfer rate grow with the growth in powder fraction. Murthy and Hegde [13] analyzed the impact of the mixed passive methods on heat transfer increment, heat efficiency and Darcy factor of a double-tube which was fitted with various turbulators and applying alumina nanomaterial. Their outcomes demonstrated that grown Nu by 29 percent and 22 percent, grown heat efficiency by 1.33 and 1.25. Numerically and empirically, Plant and Saghir [14] analyzed the effect of an Al2O3 nanomaterial on the fluid stream-based mechanism included of permeable foam to test their effect on the heat efficiency of the mechanism. Based on their achievements, the utilization of great fraction (1 percent vol) nanomaterial paired with the utilization of 2 disparate channel designs, both including permeable media led to a mean heat increment 15 percent and a highest increment of 24.5 percent in comparison to that of 2 percent fraction of alumina. Suresh et al. [15] scrutinized the thermal efficiency of helical tape in laminar stream of alumina oxide/H2O and copper oxide/H2O nanomaterials within a circular duct with fixed thermal flux boundary conditions. The authors observed that the heat efficiency of helical screw tape inserts applying copper oxide/H2O nanomaterial is greater than applying alumina oxide/H2O. Eiamsa-ard et al. [16] analyzed the convective flow within dimpled tubes mounted with TT applying titanium oxide/H2O nanomaterial as the test liquids. Their outcomes proved that the dimpled tube including TT obtained greater Nu compared to sole dimpled tube. Empirically, Hekmatipour and Jalali [17] analyzed the impact of applying CO2/thermal oil on pressure fall and convective heat transfer in an upward stream inside a tilted micro fin tube. Their findings showed that the fluid resistance grows with the increase of Re, tilted angle and nano-powder concentration.
According to aforementioned literature review, few papers have been published about combinations of twisted tape and barrier in existence of hybrid nanofluid. To reduce the exergy loss and augmentation of performance, turbulator can be utilized and changing carrier fluid to hybrid nanofluid has promising output. In current article, FVM has been applied for modeling the hybrid nanofluid exergy loss and convective heat transfer with turbulent regime. Homogeneous model for concerning the effect of hybrid nanofluid was used because of its low concentration. In next step, the geometry has been introduced and governing equations were mentioned. Forced convection in absence of buoyancy has been considered. In validation step, the best turbulent model has been introduced and then grid independency analysis has been presented. Two shapes of turbulators were utilized: sole twisted tape (TT) and TT with barrier. Friction factor, exergy loss, performance and Nusselt number have been calculated. Also, the variations of contours for isotherms, pressure and velocity have been presented.
Section snippets
Geometry and formulation
Utilizing turbulators is promising way for intensification of mixing of fluid. Fig. 1 shows tube equipped with twisted tape (TT) and barrier. Length of tube is 1.5 m and the middle section is test section where turbulators install there. The diameter of pipe is 2 inch. Pitch ratio of TT is 0.125 m. Thickness and width of barrier are 1.5 mm and 9.25 mm. Carrier fluid is hybrid nanofluid (mixture of Fe3O4+CuO and water). The properties of nano-powder and base fluid and formulations for nanofluid
Results and discussion
In current modeling, combination of obstacle and twisted tape has been compared with sole twisted tape in view of thermal performance and exergy loss. This system can be utilized as an absorber of solar system. The range of Re (5000–20,000) indicates turbulent flow and for simulation of such flow, K-ɛ has been utilized. Hybrid nanofluid has been selected as working fluid and inlet temperature is 298.15 K. To involve the feature of hybrid nanoparticles, empirical formulas were utilized as single
Conclusion
In this article, efficiency of heat exchanger with insertion of twisted tape with obstacle has been presented. Two main factors were utilized to augment the thermal performance: dispersion of hybrid nanoparticles and insertion of swirl flow device. To apply the effect of nano-powders, homogeneous model was implemented. Two different shapes of turbulator have been employed and in second one, obstacle was combined with twisted tape. This change in shape of device has promising effect of Nu while
Declaration of Competing Interest
All authors declare that there is no conflict of interest in our paper.
References (24)
- et al.
A comprehensive review on passive heat transfer enhancements in pipe exchangers
Renew. Sustain. Energy Rev.
(2013) - et al.
A comprehensive review on synthesis, stability, thermophysical properties, and characterization of nanofluids
Powder Technol.
(2019) - et al.
Use of the thermal and hydraulic length for the screening selection of turbulence promoters in tubular heat exchangers
Chem. Eng. Process. - Process Intensification
(2020) - et al.
Intensification of convective heat transfer in water/ethylene glycol based nanofluids containing TiO2 nanoparticles
Chem. Eng. Process.: Process Intensification
(2014) - et al.
Turbulent heat transfer and friction factor of Al2O3 Nanofluid in circular tube with twisted tape inserts
Int. J. Heat Mass Transf.
(2010) - et al.
Heat transfer enhancement by multiple twisted tape inserts and TiO2/water nanofluid
Appl. Therm. Eng.
(2014) - et al.
Geometrical effect coupled with nanofluid on heat transfer enhancement in heat exchangers
Int. J. Thermofluids
(2021) - et al.
A printed-circuit heat exchanger consideration by exploiting an Al2O3-water nanofluid: effect of the nanoparticles interfacial layer on heat transfer
Therm. Sci. Eng. Progr.
(2021) - et al.
Exergy destruction minimization: a principle to convective heat transfer enhancement
Int. J. Heat Mass Transf.
(2018) - et al.
Numerical and experimental investigation of high concentration aqueous alumina nanofluids in a two and three channel heat exchanger
Int. J. Thermofluids
(2021)
Comparative study on thermal performance of helical screw tape inserts in laminar flow using Al2O3/water and CuO/water nanofluids
Superlattices Microstruct.
A new k-ε eddy viscosity model for high Reynolds number turbulent flows
Comput. Fluids
Cited by (15)
Numerical solution for optimization of curved turbulator geometry in a double-pipe heat exchanger containing two-phase Cu-GO/Therminol VP-1 hybrid nanofluid to achieve maximum exergy efficiency
2023, Engineering Analysis with Boundary ElementsThe first and second law analyses of thermodynamics for CoFe<inf>2</inf>O<inf>4</inf>/H<inf>2</inf>O flow in a sudden expansion tube inserted elliptical dimpled fins
2023, International Journal of Mechanical SciencesThe effect of pressure gradient on MHD flow of a tri-hybrid Newtonian nanofluid in a circular channel
2023, Journal of Magnetism and Magnetic MaterialsCitation Excerpt :Mohamed et al. [55] developed an analytic resolution for pulse flowing and heat transference in a pipe depending on the Bessel transforms. At various t values, Figure 2 displays the rapidity outlines of the existing study and Mohamed et al. [55]. According to Figure 2, the current investigation's velocity profile results are identical to those reported by Mohamed et al. [55].
Turbulent flow thermal characteristics in a pipe with ring insert: An experimental and numerical study
2022, Chemical Engineering and Processing - Process IntensificationNovel self-join winglet vortex generators for enhanced heat transfer of turbulent airflow in round tubes
2022, International Communications in Heat and Mass TransferSimulation of hybrid nanofluid flow within a microchannel heat sink considering porous media analyzing CPU stability
2022, Journal of Petroleum Science and EngineeringCitation Excerpt :Modern industries need powerful, fast electric devices with high-performance and small size (Sheikholeslami and Ali Farshad, 2021; Zhao et al., 2021a, 2021b; Guo et al., 2021a; Said et al., 2021). A device with these specifications often has high heat generation per unit of volume, which must be dissipated with the aid of colling technics to increase the lifetime and performance of electric components (Xiang et al., 2020; Jafaryar and Sheikholeslami, 2021; Zhao et al., 2021c; Yadav et al., 2021; Zhong et al., 2021). Traditional cooling methods through natural and forced convection, which are easy and inexpensive, but they are not able to remove dramatically increased heat flux produced in these electric devices (Chu et al., 2020a, 2020b; Sheikholeslami et al., 2021a, b; Qin, 2021a; Jiang et al., 2021).