Heat transfer augmentation of Al₂O₃-Cu/water hybrid nanofluid in circular duct with inserts

Figures & data

Table 1. Summary of some of the related literatures review

Authors	Parameters	Main findings
Sakanova et al., 2014	Al2O3/water nanofluid $\phi =0.01,0.05$	Al2O3 water-based nanofluid is used as a coolant to improve heat transfer performance, with volume concentrations of 1% and 5%. According to the results, the nanofluids produce superior cooling performance at larger concentrations; consequently, concentrations of 5% and 1% improve cooling performance by 17.3% and 10.6%, respectively.
Raei et al., 2016	Al2O3/water nanofluid $\phi =0.05\mathrm{\%},0.15\mathrm{\%}$	The findings indicated that pure water has a lower Nusselt number than nanofluids. Additionally, when the flow rate, temperature, and particle volume percentage of the nanofluid increased, so did the Nusselt number. The biggest improvements in this study’s heat transfer coefficient and friction factor, which were 23 and 25%, respectively, were at a nanoparticle concentration of 0.15%.
Abdollahi et al., 2017	SiO2, Al2O3, ZnO, CuO, base fluid water $\phi =0.01,0.015,0.02$$d_{np}=30,40,60nm$	The findings showed that among the investigated nanofluids and pure water, SiO2 nanofluid exhibits the highest Nusselt number value. The average Nusselt number improved as the volume fraction of nanoparticles increased.
Peyghambarzadeh et al.,	CuO, Al2O3, base fluidwater $\phi =0.01,0.02,0.03,0.04$	CuO nanofluids at 0.2% and 1% volume concentrations increased the heat transfer coefficient to 27.0% and 49%, respectively, but had a higher pressure drop when compared to pure water.
Xia et al., 2016	Al2O3, TiO2, base fluidwater $\phi =0.001,0.005,0.01$	Al2O3 and TiO2 nanofluids exhibit increased thermal conductivity and dynamic viscosity with increasing volume concentration. Utilizing Al2O3 nanofluids, the performance of heat transfer in a fan-shaped microchannel heat sink is improved as compared to a rectangular microchannel heat sink.

Figure 1. (a) Geometry, (b) mesh, and (c) twisted tape.

Table 2. Thermophysical properties of water and hybrid nanofluid Al₂O₃-Cu/water (Hamdi et al., 2019)

Material	Density, $\rho$ (kg/m^3)	Heat capacity, Cp (J/kg · K)	Thermal conductivity, k(W/m · K)	Dynamic viscosity, $\mu$(kg/m · s) $\times {10}^{-3}$
Water	995.7	4178.00	0.615	0.800
0.1% Hybrid Nanofluid	998.91	4163.53	0.619	0.900
0.5% Hybrid Nanofluid	1011.74	4106.58	0.633	1.200
1% Hybrid Nanofluid	1027.78	4037.40	0.652	1.602
2% Hybrid Nanofluid	1059.86	3905.30	0.685	1.935

Figure 2. Grid resolution test for PTT tube. (a) Cell_ 26028449 (Model 1). (b) Cell_3364281 (Model 3). (c) Cell_3114836 (Model 2).

Figure 3. Comparison of Nusselt number of water and 1% hybrid nanofluid in a circular tube.

Figure 4. Comparison friction factor of 1% hybrid nanofluid in circular tube and PTT tube.

Figure 5. PEC of 1% Al₂O₃-Cu/water hybrid nanofluid in PT and PTT tube.

Figure 6. Temperature contour plot for PT for water, Re = 20,000, at different axial locations.

Figure 7. Temperature contour plot for PT for Al₂O₃-Cu/water, Re = 20,000, at different axial locations.

Figure 8. Velocity contour plot for PT for Al₂O₃-Cu/water, Re = 20,000, at different axial locations.

Figure 9. Temperature contour plot for PTT for Al₂O₃-Cu/water, Re = 20,000, at different axial locations.

Figure 10. Velocity contour plot for PTT for Al₂O₃-Cu/water, Re = 20,000, at different axial locations.

Table

Cu	copper
d	diameter, m
CuO	copper oxide
L	length, m
CHTC	convective heat transfer coefficient
w	width, m
h	convective heat transfer coefficient, kW/m^2.K
Nu	Nusselt number
hav	average convective heat transfer coefficient
kW/m^2.K q′′	heat flux, kW/m^2
SiO2	silicon oxide
Pr	Prandtl number
Al2O3	aluminum oxide
Re	Reynold number
$\phi$	volume concentration
$f$	friction factor
PEC	performance evaluation criteria
PPT	plain twisted tape
$y/w$	twist ratio
PT	plain tube/circular tube
Al2O3–Cu/H2O	alumina–copper–water
ZnO	zinc oxide
A	cross-sectional area, m^2
Tw	wall temperature, K
Tf	film temperature, K
Tin	intake temperature, K
Tout	outlet temperature, K
ZnO	zinc oxide

Sakanova, A., Yin, S., Zhao, J., Wu, J. M., & Leong, K. C. (2014). Optimization and comparison of double-layer and double-side micro-channel heat sinks with nanofluid for power electronics cooling. Applied Thermal Engineering, 65(1–2), 124–134. https://doi.org/10.1016/j.applthermaleng.2014.01.005

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Raei, B., Shahraki, F., & Mohammad Jamialahmadi, S. M. P. (2016). Experimental study on the heat transfer and flow properties of -Al2O3/water nanofluid in a double-tube heat exchanger. Journal of Thermal Analysis and Calorimetry. https://doi.org/10.1007/s10973-016-5868-x

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Abdollahi, A., Mohammed, H. A., Vanaki, M., Osia, A., & Haghighi, M. R. G. (2017). Fluid flow and heat transfer of nanofluids in microchannel heat sink with V-type inlet/outlet arrangement. Alexandria Engineering Journal, I. https://doi.org/10.1016/j.aej.2016.09.019

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Xia, G. D., Liu, R., Wang, J., & Du, M. (2016). The characteristics of convective heat transfer in microchannel heat sinks using Al2O3 and TiO2 nanofluids. International Communications in Heat and Mass Transfer, 76, 256–264. https://doi.org/10.1016/j.icheatmasstransfer.2016.05.034

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Hamdi, E. A., Salman, B. H., & Sh Kerbeet, A. (2019). Heat transfer enhancement of turbulent forced nanofluid flow in a duct using triangular rib. International Journal of Heat and Mass Transfer, 134. https://doi.org/10.1016/j.ijheatmasstransfer.2018.12.163

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