## 3 Results and Discussions
### The Influence of Temperature and Velocity Contours on Hybrid Nanofluid Flow
Figure 10 exemplifies the effect of the HNF with different VF on the ratio of the averaged Nu of the HNF and that of the base fluid for different Re and inlet temperature \(T\) = 313 K. This figure demonstrates that the use of NF at \(T\) = 313 K leads to minimum Nu in comparison with the base fluid. Figure 8: Influence of using HNF with different VF on HT coefficient for various Re and inlet temperature \(T\) = 313 K.  
Figure 9: Influence of using HNF with different volume fractions on HT coefficient for various Re and inlet temperature \(T\) = 323 K.  
The Effects of Hybrid Nanofluid with Different Volume Fractions on Average Nu Ratio at Various Re and Selected Inlet Temperature  
Figure 10 shows the effect of the HNF with different VF on the ratio of the averaged Nu of the HNF and that of the base fluid for different Re and inlet temperature \(T\) = 323 K. It is shown that the use of the EG/MgO-MWCNT HNF with a volume fraction of 0.4% at \(T\) = 323 K leads to maximum Nu in comparison with the base fluid for all Re. It is also revealed that at \(T\) = 323 K, the use of the EG/MgO-MWCNT HNF with volume fractions of 0.1% and 0.2% is efficient only at a very low Re. Figure 11 shows the influence of the HNF with a VF of 0.4% on the Nusselt ratio due to NF flow and pure flow for various Re and inlet temperatures \(T\) = 313 K and 323 K. It is found that higher temperatures lead to higher Nusselt ratios. The Nusselt ratio is about 1.365 and 1.181 at \(T\) = 323 K and \(T\) = 313 K, respectively. The Nusselt ratio decreases slightly with the Re. Fluid flow velocity increases with the Re, disturbing the flow and increasing the HT rate. Figure 11: Effects of HNF with different VF on average Nu ratio for different Re and inlet temperature \(T\) = 323 K.  
Figure 10: Effects of HNF with different VF on average Nu ratio for different Re and inlet temperature \(T\) = 313 K.  
The Effects of Hybrid Nanofluid with Various Volume Fractions on Hydraulic Power at Various Re and Selected Inlet Temperature  
Figure 12 shows the effect of hybrid nanofluid with various volume fractions on hydraulic power for different Re and inlet temperature \(T\) = 313 K. It is found that as the Re increases, the pumping power enhances. Fluid flow velocity increases with the Re, disturbing the flow and increasing the HT rate. The use of the EG/MgO-MWCNT HNF with a volume fraction of 4% leads to a higher pumping power compared to the other investigated cases for all Re. Figure 13 shows the result of the HNF with various volume fractions on hydraulic power for different Re and inlet temperature \(T\) = 323 K. It is shown that the pumping power enhances with the Re. The use of the EG/MgO-MWCNT HNF with a volume fraction of 0.4% leads to higher pumping power in comparison with volume fractions of 0.1% and 0.2% for all Re. Figure 12: Effects of HNF with volume fraction of 0.4% on PD ratio for different Re and inlet temperature \(T\) = 313 K and 323 K.  
Figure 13: Influence of HNF with different VF on hydraulic power for different Re and inlet temperature \(T\) = 313 K.  
Figure 14 illustrates the effect of the HNF with different VF on PD for various Re and inlet temperatures \(T\) = 313 K and \(T\) = 323 K. It is concluded that higher temperatures lead to larger PD. The use of the EG/MgO-MWCNT NF with a VF of 0.4% leads to less PD in compression with the other VF. Therefore, EG/MgO-MWCNT NF with a VF of 0.4% is introduced as the optimum case among all studied ones. The Effects of Hybrid Nanofluid with Various Volume Fractions on Pressure Reduction on Thermal Entropy Generation at Various Re and Selected Inlet Temperature  
Figure 15 presents the effect of the HNF with various VF on % pressure reduction (PR) percentages on thermal entropy generation for various Re and inlet temperatures (a) \(T\) = 313 K and (b) \(T\) = 323 K. As can be seen in these figures, with an increasing Reynolds number, no significant change in pressure drop values occurs at the studied temperatures.