Thermo-hydraulic investigation of Al2O3/water nanofluid flow in an oval tube fitted with dual conical twisted-tape inserts: parametric studies
| Autor: | Ramin Mashayekhi, S. Mohammadreza Golestanha, Alireza Rahbari, Davood Toghraie |
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| Rok vydání: | 2021 |
| Předmět: |
Pressure drop
Materials science 020209 energy Heat transfer enhancement General Physics and Astronomy Reynolds number 02 engineering and technology Conical surface Mechanics 021001 nanoscience & nanotechnology Secondary flow Nusselt number Physics::Fluid Dynamics symbols.namesake Nanofluid 0202 electrical engineering electronic engineering information engineering symbols 0210 nano-technology Intensity (heat transfer) |
| Zdroj: | The European Physical Journal Plus. 136 |
| ISSN: | 2190-5444 |
| DOI: | 10.1140/epjp/s13360-021-01664-w |
| Popis: | This work presents the thermo-hydraulic performance of water–Al2O3 nanofluid flow in an oval tube fitted with two parallel conical twisted strips in different alignments including staggered with four wings (S-4), staggered with five wings (S-5), non-staggered with 4 wings (NS-4), and non-staggered with five wings (NS-5). A detailed parametric study is carried out to evaluate the impact of different arrangements of conical strip insert, Reynolds number, and volume fraction of nanoparticles ( $$\phi $$ ) on the heat transfer and pressure drop of the oval tube. It is found out that the highest Nusselt number is obtained in the case of NS-5 at Re = 250 and $$\phi =3$$ –86.9% higher than that of the plain tube. To investigate the effectiveness of conical twisted strips in terms of heat transfer enhancement, the intensity of the secondary flow generated by two parallel conical strips is represented by the vorticity isosurfaces. The NS-5 configuration generates stronger secondary flow at the vicinity of the heated wall. The increase in Nusselt number comes at the expense of a much higher friction factor relative to other configurations. Performance evaluation criterion (PEC) is calculated to identify a configuration with higher heat transfer performance at the lowest friction factor. The maximum PEC of 1.52 is obtained in the case of S-5 at Re = 250 and $$\phi =3{\%}$$ . |
| Databáze: | OpenAIRE |
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