Numerical investigation of turbulent Cu-water nanofluid in heat exchanger tube equipped with perforated conical rings

Nakhchi, M.E.; Esfahani, Javad Abolfazli

doi:10.1016/j.apt.2019.04.009

Cited by 72 publications

(23 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Different methods have been employed for thermal performance intensification of these systems by considering size and cost reductions. To this end, several passive methods are suggested by scientists to improve the thermal efficiency of mechanical structures in the past few years, like twisted tapes [1,2], perforated turbulators [3,4], hollow cylinders [5], conical rings [6,7] and employing nanofluids [8][9][10] as the operating cooling fluid.…”

Section: Introductionmentioning

confidence: 99%

CFD approach for two-phase CuO nanofluid flow through heat exchangers enhanced by double perforated louvered strip insert

Nakhchi

Esfahani

2020

Powder Technology

Self Cite

View full text Add to dashboard Cite

In this study, turbulent flow characteristics of CuO-water nanofluid through heat exchanger pipe enhanced with louvered strips are numerically investigated. Nanoparticles volume fraction    varied from 0 to 2% . The louvered strips are mounted in single and double geometries. The slant angle    and the Reynolds number (Re) are within 15 25    and between 5,000 and 14,000, respectively. (RNG) k   model is employed based on the finite volume technique. The results illustrated that strong flow disturbance between the wall and the louvered strip is the main reason for turbulent kinetic energy increment. Besides, the nanoparticles improve the thermophysical properties of the working fluid, which results in better heat transfer. The Nu number increases 15.6% by using nanofluid instead of water at Re 14000  . The highest thermal enhancement parameter of 1.99 is obtained at Re 14000  by using double perforated louvered strip with 25    . The recirculating flow inside the holes can significantly improve the thermal performance.

show abstract

Section: Introductionmentioning

confidence: 99%

CFD approach for two-phase CuO nanofluid flow through heat exchangers enhanced by double perforated louvered strip insert

Nakhchi

Esfahani

2020

Powder Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…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%

“…Nakhchi and Esfahani [12] used perforated conical rings through the heat exchangers with the turbulent flow regime. They employed Cu-water nanofluid as the working fluid.…”

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

View full text Add to dashboard Cite

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.

show abstract

“…As the literature reviews, the advantages of the conical ring (Nakhchi and Esfahani (2019a), Nakhchi and Esfahani (2019b), Ibrahim et al (2019), Mohammed (2019), Bahiraei et al (2020c, d)) and baffle , , Wang et al (2019), Liu et al (2019), , Li et al (2019), , Chai et al (2018), Chai et al (2019), Ahmed et al (2019), Boonloi and Jedsadaratanachai (2019c)) or rib (Ameur and Menni (2019), Karami et al (2019), Cao et al (2019), Chen et al (2019), Arani and Moradi (2019), Bahiraei et al (2020a)) are focused. The prominent point of the conical ring is the convenience for the installation and maintenance, while the rib and baffle give high heat transfer rate, especially, V-shape and wavy configuration.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigations on Flow Structure and Heat Transfer in a Square Duct Equipped With Double v-Orifice

Jedsadaratanachai¹,

Boonloi²

2020

Frontiers in Heat and Mass Transfer

View full text Add to dashboard Cite

Numerical predictions on heat transfer characteristic, flow topology and thermal performance assessment in a square duct are presented. The passive technique, insertion of the vortex generator, is opted to develop the heat transfer rate in the square duct heat exchanger. The vortex generator of the present research is Double V-Orifice (DVO). The square duct equipped with DVO is tested with various parameters. The influences of DVO height, b, to the duct height, H, or b/H, gap spacing between the outer edge of the orifice and the duct wall, s, to the duct height or s/H and flow directions (tip-pointing-Downstream and tip-pointing-Upstream) on flow pattern and heat transfer profile are considered for laminar flow regime with similar pitch, P, to duct height or P/H of 1. The Reynolds number, Re, based on the hydraulic diameter, Dh, of the square duct around 100-2000 is discussed. The numerical model is solved with the commercial software (finite volume method). As the numerical result, the square duct inserted with the DVO offers greater Nusselt number, Nu, than the plain duct around 1.00-14.80 times. The maximum thermal enhancement factor, TEF, for the square duct inserted with the DVO is found to be about 3.60 depended on s/H, b/H and flow direction. The flow and heat transfer profiles in the square duct inserted with the DVO are also illustrated.

show abstract

Numerical investigation of turbulent Cu-water nanofluid in heat exchanger tube equipped with perforated conical rings

Cited by 72 publications

References 30 publications

CFD approach for two-phase CuO nanofluid flow through heat exchangers enhanced by double perforated louvered strip insert

CFD approach for two-phase CuO nanofluid flow through heat exchangers enhanced by double perforated louvered strip insert

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

Numerical Investigations on Flow Structure and Heat Transfer in a Square Duct Equipped With Double v-Orifice

Contact Info

Product

Resources

About