Entropy production analysis for nanofluid flow through a channel with perforated transverse twisted-baffles

ABSTRACT

In the present paper, an entropy production analysis is carried out on the heat transport and nanofluid flow through a 3D channel equipped with perforated transverse twisted-baffles. The finite volume technique is used for the simulation of the heat transport in the system. The Brownian motion of the nanoparticles is included in the simulation. Twisted baffles with three pitch intensities ($\gamma ={180}^{\circ },{360}^{\circ },{540}^{\circ }$) are mounted inside the duct. The angle of twisted baffles is varied from $0^{\circ }$ (vertical) to ${90}^{\circ }$ (horizontal). The number of holes considered in this study is 0, 4, 6, and 8. Alumina/water nanofluid with the nanoparticles concentration of 3% is employed as the fluid. The influences of different parameters, including the angle and pitch of baffles and the number of holes, on the heat transport, pressure loss, and entropy production are studied. The results show that with increasing the number of holes on the baffles, the heat transport coefficient is boosted and the pressure loss in the channel is declined. The minimum pressure loss can be observed for the case of the perforated baffle with eight holes and the pitch of $\gamma ={540}^{\circ }$. For this case, the pressure loss decreases by 1.3% and the heat transport coefficient increases about 3.9% as compared to those for the empty channel. The maximum performance evaluation criterion can be achieved as the perforated baffles with four holes and the pitch of $\gamma ={540}^{\circ }$ are used and it has the value of 1.3 at $\theta ={45}^{\circ }$. As the baffle pitch is boosted from $\gamma ={180}^{\circ }$ to $\gamma ={360}^{\circ }$, the heat transport coefficient is increased slightly. This increase is 2.5% at $\theta ={45}^{\circ }$. The viscous entropy production declines as the holes are created on the baffles. By moving along the channel length, the thermal irreversibility is extended toward the center of the channel owing to thickening the thermal boundary layer.

Keywords:

• Alumina/water nanofluid
• Brownian motion
• Perforated transverse twisted-baffles
• Second law analysis

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Disclosure statement

No potential conflict of interest was reported by the author(s).