Forced convection enhancement in channels with transversal ribs and nanofluids

Andreozzi, Assunta; Manca, Oronzio; Nardini, Sergio; Ricci, Daniele

doi:10.1016/j.applthermaleng.2015.12.140

Cited by 71 publications

(19 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is express as

N_{S} = \frac{normalexergy destr .}{normalinput heat} = \frac{S_{gen} T_{in}}{\overset{m}{true} C_{p} normalΔ T} .

The thermodynamic second law efficiency η II of a thermal system is given as

η_{I I} = \frac{W_{\max}}{W_{act}} = ((), 1 - N_{s}) .

Optimum design of the thermal system from entropy generation minimization theory requires the entropy production to be minimized while convective heat transfer is maximized. To establish the best configuration of a thermal system, a dimensionless parameter (E P ) called thermal performance factor is defined as the ratio of average Nusselt number to entropy generation number given by Equation

E_{p} = \frac{Nu}{N_{s}} .

As stated above, there are two terms that contribute to entropy production in a thermal system: the entropy production due to thermal effect and fluid flow, but often these two vary inversely to each other.…”

Section: Problem Statementmentioning

confidence: 99%

Numerical investigation of thermal performance of single‐walled carbon nanotube nanofluid under turbulent flow conditions

Fadodun

Amosun

Salau

et al. 2019

Engineering Reports

View full text Add to dashboard Cite

In this paper, a numerical study is performed to investigate the effect of Reynolds number and nanoparticle concentration on the thermal performance of single‐walled carbon nanotubes (SWCNTs) nanofluids flowing through a straight pipe with constant heat flux in a turbulent flow regime. The governing equations (continuity, momentum, energy, rate of turbulent production, and rate of turbulent dissipation) are solved using a computational fluid dynamic approach (ie, finite volume method). In the sensitivity analysis, the Reynolds number is varied between (10 000‐200 000) and nanoparticle concentration between (0%‐0.25%). The simulation results show that convective heat transfer (average Nusselt number) increases by 7.48% while the pressure drop and pumping power increase by 119% and 199%, respectively. In addition, at low Reynolds number (104), increase in nanoparticle concentration (0%‐0.25%) decreases entropy production rate by 16.95%. However, at higher Reynolds number (2*105), the entropy production rate increases by 149.77%. Furthermore, other results such as entropy generation number, Bejan number, second thermodynamic law efficiency, and thermal performance factor, which combine the first and second law of thermodynamics, are presented as functions of Reynolds number and nanoparticle's concentration. The overall result shows that SWCNT nanofluid will only be beneficial at low Reynolds number of (10 000‐50 000).

show abstract

“…This is express as

N_{S} = \frac{normalexergy destr .}{normalinput heat} = \frac{S_{gen} T_{in}}{\overset{m}{true} C_{p} normalΔ T} .

The thermodynamic second law efficiency η II of a thermal system is given as

η_{I I} = \frac{W_{\max}}{W_{act}} = ((), 1 - N_{s}) .

E_{p} = \frac{Nu}{N_{s}} .

Section: Problem Statementmentioning

confidence: 99%

Numerical investigation of thermal performance of single‐walled carbon nanotube nanofluid under turbulent flow conditions

Fadodun

Amosun

Salau

et al. 2019

Engineering Reports

View full text Add to dashboard Cite

show abstract

“…The Nu ୟ୴ୣ through the ribbed channels was enhanced with the increase of φ and Re ୬ and with the decrease of݀ . Andreozzi et al (2016) examined the effect of different rib shapes on heat transfer and ‫݈ܣ‬ ଶ ܱ ଷ െ ‫ܪ‬ ଶ ܱ nanofluid flow characteristics of a channel. Simulations for different ߮ from 0%, pure ‫ܪ‬ ଶ ܱ, to 4% and flow parameter between 20,000 and 60,000 are accomplished.…”

Section: Introductionmentioning

confidence: 99%

DEVELOPMENT OF NEW CORRELATIONS FOR NUSSELT NUMBER AND FRICTION FACTOR OF TiO_2/WATER BASED NANOFLUID FLOW IN V-PATTERN PROTRUSION RIBBED SQUARE CHANNEL

Kumar¹,

Singh²,

Maithani³

et al. 2018

Frontiers in Heat and Mass Transfer

View full text Add to dashboard Cite

Nanofluids play important roles in the heat transfer and flow characteristics in ribbed square channels. Systematic experiments are conducted to measure heat transfer enhancement and TiO ଶ െ H ଶ O based nanofluid flow characteristics on a protruded with combined V-type ribbed square channel. Reynolds number studied in the channel range from 4000-18000. Investigational parameters of square channel contain, volume fraction range of 1.0-4.0%, particle diameter range of 30nm-45nm, relative protruded rib height range of 0.10-0.25, ratio of protruded height to print diameter range of 0.8-2.0, relative protruded rib pitch ratio range of 2.0-3.5 and angle of attack of 30 0 -75 0 respectively. Results indicates that the thermal performance of the protruded combined V-type ribbed square channel falls with increasing Reynolds number. The highest value of thermal hydraulic performance parameter is found to be 3.21for the range of parameters investigated. Correlations predicting Nusselt number and friction factor as a function of volume fraction, particle diameter range, relative protruded rib height, ratio of protruded height to print diameter, relative protruded rib pitch ratio, angle of attack and flow parameter. The correlations for Nusselt number and friction factor have also been developed on the basis of experimental data with considerable good accuracy.

show abstract

“…It was concluded that the trapezoidal shaped ribs provide the highest heat transfer enhancement. Numerical study of nanofluid forced convection flow in triangular ribbed microchannel has been carried out by Andreozzi et al [16]. They have exanimated the effect of ribs shapes on heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Cooling a Ribbed Microchannel Using Nanofluid

Madani¹

2018

Journal of Thermal Engineering

View full text Add to dashboard Cite

A 2-D numerical investigation was carried out to study the effect of spacing between ribs on nanofluid flow and heat transfer inside a horizontal micro-channel. Two identical ribs were placed at the lower wall of micro-channel with variable spacing between them. The alumina oxide nanoparticles was suspended in water as based fluid at different volume fraction 0, 2 and 4%. The finite volume method was used to solve the continuity, momentum and energy equations. The effects of different parameters such as nanoparticles volume fraction, Reynolds number, and the spacing between ribs has been evaluated. The results showed that increasing nanoparticles volume fraction and Reynolds number significantly enhanced the heat transfer and the Poiseuille number. The presence of ribs improves the heat transfer. However, increasing the spacing between ribs leads to decrease the heat transfer rate.

show abstract

Forced convection enhancement in channels with transversal ribs and nanofluids

Cited by 71 publications

References 53 publications

Numerical investigation of thermal performance of single‐walled carbon nanotube nanofluid under turbulent flow conditions

Numerical investigation of thermal performance of single‐walled carbon nanotube nanofluid under turbulent flow conditions

DEVELOPMENT OF NEW CORRELATIONS FOR NUSSELT NUMBER AND FRICTION FACTOR OF TiO_2/WATER BASED NANOFLUID FLOW IN V-PATTERN PROTRUSION RIBBED SQUARE CHANNEL

Numerical Investigation of Cooling a Ribbed Microchannel Using Nanofluid

Contact Info

Product

Resources

About