Cu-water nanofluid flow and heat transfer in a heat exchanger tube equipped with cross-cut twisted tape

Nakhchi, M.E.; Esfahani, Javad Abolfazli

doi:10.1016/j.powtec.2018.08.087

Cited by 90 publications

(29 citation statements)

References 31 publications

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“…Sayed et al 3 studied the influence of thermal transportation and alternative current on the peristaltic flow of a viscous dielectric fluid. Nakhchi and Esfahani 4 examined a mathematical investigation for Cu–water nanoliquid flow through a spherical cylinder implanted with cross-cut warped tape with an alternative axis (CCTA). Furthermore, the reader can study about nanofluid in Refs.…”

Section: Introductionmentioning

confidence: 99%

Insight into the dynamics of second grade hybrid radiative nanofluid flow within the boundary layer subject to Lorentz force

Jawad

Saeed

Tassaddiq

et al. 2021

Sci Rep

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The magnetohydrodynamic hybrid second-grade nanofluid flow towards a stretching/shrinking sheet with thermal radiation is inspected in current work. Main concern of current investigation is to consider hybrid $$Al_{2} O_{3} - Cu$$ A l 2 O 3 - C u nanofluid which is perceived by hanging two dissimilar kinds of nanoparticles known as alumina and copper within the base fluid. The fluid motion is produced by non-linear stretching/shrinking sheet. The modeled equations which comprise of energy, motion and continuity equations are changed into dimensionless form using group of similar variables. To determine the solution of transformed problem, the Homotopy Analysis technique is used. The findings of this work revealed that the magnetic parameter improves the heat transfer rate. This work also ensures that there are non-unique solutions of modeled problem for shrinking case and a unique solution for stretching case. Higher values of $${\text{Re}}_{x}$$ Re x results in declining of flow field. Rise in $$M$$ M agrees to a decline in velocity distributions. Higher values of second order fluid parameter reduces the viscosity of fluid and accordingly velocity increases. Velocity profile is also a decreasing function of volume friction.

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Section: Introductionmentioning

confidence: 99%

Insight into the dynamics of second grade hybrid radiative nanofluid flow within the boundary layer subject to Lorentz force

Jawad

Saeed

Tassaddiq

et al. 2021

Sci Rep

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show abstract

“…These modified approaches include a cross-cut twisted tape with an alternate axis (CCTA) with a Cu/Water nanofluid as the working fluid [8,9], twin co-twisted tapes and twin counter-twisted tapes (CoTs and CTs) with a graphene-platinum nanofluid as the working fluid [10], overlapped dual twisted tapes (O-Dts) with a TiO2/Water nanofluid as the working fluid [11], helical twisted tape with an Al 2 O 3 / water nanofluid as the working fluid [12], twisted tape with dimples and protrusions with an Al 2 O 3 /Water nanofluid as the working fluid [13], dual co-twisted tapes and dual counter-twisted tapes (D-Co-TTs and D-C-TTs) with an Al 2 O 3 /Water nanofluid as the working fluid [14], rectangular-cut-on-its-rib twisted tape with four types of nanofluids as working fluids (TiO 2 /Water, BeO/Water, ZnO/Water, and CuO/Water) [15], twisted tapes with various progression ratios (RGPR and IGPR) with an Al 2 O 3 /Water nanofluid as the working fluid [16], spiky twisted tape with three types of nanofluids as the working fluid (Cu/Water, Fe/Water, and Ag/Water) [17], and trapezoidally cut twisted tape with an Fe 3 O 4 /Water nanofluid as the working fluid [18]. The simultaneous use of these two passive methods increased η by a factor 1.2-1.5 for Re between 4000-10,000 compared to classic twisted tape with water as the working fluid.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Analysis of the Thermal Performances of SiC/Water and Al2O3/Water Nanofluid Inside a Circular Tube with Constant-Increased-PR Twisted Tape

2020

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The simultaneous use of two passive methods (twisted tape and a nanofluid) in a heat transfer system will increase the average Nusselt number (Nu) of the system. However, the presence of inserts and nanoparticles inside the tube will create higher pressure drop (ΔP) in the system, which can eventually affect the overall enhancement ratio (η), especially at higher Reynolds numbers (Re). Several modifications of twisted tapes have been made to reduce ΔP, but most showed a decreasing trend of η as Re increased. The objective of this study is to design a new geometry of twisted tape that yields a larger value of Nu and a smaller value of ΔP, which can result in a larger value of η especially at higher Re. A simulation and experimental analysis are conducted in which Re ranges from 4000–16,000 with two types of nanofluids (SiC/Water and Al2O3/Water) at various values of the volume fraction, (φ) (1–3%). ANSYS FLUENT software with the RNG k-ɛ turbulent model is adopted for the simulation analysis. Three types of twisted tape are used in the analysis: classic twisted tape with a pitch ratio of 2 (TT PR2), constant-increasing-pitch-ratio twisted tape (TT IPR) and constant-decreasing-pitch-ratio twisted tape (TT DPR). The use of TT IPR generates a stronger swirling flow at the inlet of the tube and smaller ∆P, especially near the outlet region. The highest value of η is obtained for 3% SiC/Water nanofluid that is flowing through a smooth circular tube with TT IPR inserts at Re of 10,000.

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“…Several researchers conducted experimental and numerical simulations in the field of energy performance augmentation of turbulent and laminar flows by utilizing various active and passive methods, Such as twisted tapes [4][5][6], ribbed and corrugated channels [7][8][9], wavy surfaces [10,11], conical rings [12], louvered strips [13], hollow cylinders [14], asymmetric sinusoidal channels [15,16], nanofluids [17][18][19][20][21], baffle turbulators [22][23][24], helical screw tapes [25,26], rotating two-pass channels [27] and triangular obstacles [28].…”

Section: Introductionmentioning

confidence: 99%

Turbulent Flows Inside Pipes Equipped With Novel Perforated V-Shaped Rectangular Winglet Turbulators: Numerical Simulations

Nakhchi

Rahmati

2020

Journal of Energy Resources Technology

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In this study, computational simulations have been performed to investigate the turbulent characteristics and energy consumption through heat exchanger tubes equipped by new perforated V-shaped rectangular winglet (PVRW) turbulators. The effects of the holes intensity on the velocity and temperature contours are additionally investigated. The Reynolds number, hole diameter ratio, and the number of holes selected are in the range of 5000 ≤ Re ≤ 18,000, 0 ≤ DR ≤ 0.40, and 0 ≤ N ≤ 14, respectively. Renormalization group (RNG) k–ε turbulent model which is a finite volume solver is utilized for the computational fluid dynamics (CFD) simulation. It was noticed that the proposed perforated turbulators could considerably intensify the thermal performance compared to typical VRW inserts. It is found that the recirculating flow generated by the PVRW augments the fluid mixing and transfers the heat from the pipe walls to the core of the tube. The simulations illustrate that the amount of heat transfer enhances 25.2% reducing the DR from 0.4 to 0.13 at Re = 18,000 and N = 14. Also, using PVRW turbulators with N = 7 and DR = 0.26 augments the average Nusselt number around 354.3% compared to the circular pipe without inserts. The highest thermal efficiency parameter of η = 2.25 could be obtained at Re = 5000 for the heat exchangers fitted by vortex generators with N = 14 and DR = 0.26.

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Cu-water nanofluid flow and heat transfer in a heat exchanger tube equipped with cross-cut twisted tape

Cited by 90 publications

References 31 publications

Insight into the dynamics of second grade hybrid radiative nanofluid flow within the boundary layer subject to Lorentz force

Insight into the dynamics of second grade hybrid radiative nanofluid flow within the boundary layer subject to Lorentz force

Numerical and Experimental Analysis of the Thermal Performances of SiC/Water and Al2O3/Water Nanofluid Inside a Circular Tube with Constant-Increased-PR Twisted Tape

Turbulent Flows Inside Pipes Equipped With Novel Perforated V-Shaped Rectangular Winglet Turbulators: Numerical Simulations

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