## 7 Numerical Results and Discussion
### Numerical Simulation of the Modification Models  
Figure 15 illustrates the velocity field at a vertical section of +40 mm to the CBM referenced around the cooling fan. From the Figure, it can be seen that there was a smooth flow around the compressor in the modified model (c) due to the presence of a vent at the rear of the compressor when compared to models (a) and (b). In addition, it can be seen that the flow passed through the upper section of the compressor due to the fact that the flow stopped up at the vent of the condenser. In addition, model (d) shows lots of flows at the upper and lower sections of the compressor according to the installation of events at the rear and around the compressor when compared with the model (c). In addition, there were smooth flows due to the discharge of flow that was generated at the space between the compressor and the condenser and was congested at the upper section of the compressor. Figure 16 illustrates the velocity field at a vertical section of \(-20\) mm to the CBM around the cooling fan. As shown in the figure, regarding the models (b-d) that ensure the vents at the left section of the compressor, it can be seen that the flow progressed around the compressor, whereas model (d) represents the most active movement. This shows that all modified models represented smooth flow around the compressor when compared to the original model. Figure 14: Modified structure of the CBM. Figure 17 illustrates the velocity field at a horizontal section of +20 mm to the CBM around the cooling fan. From the Figure, it can be seen that the models (b-d) showed the discharge of flows to the lower section of the compressor, whereas model (c) showed the flow that progressed to the compressor due to the cut-off of the vent of the condenser. Moreover, it can be seen that in model (d), flow was generated at the upper section due to the influence of the right upper vent of the compressor. Figure 18 illustrates the velocity field at a horizontal section of \(-40\) mm to the CBM around the cooling fan. From the Figure, it can be seen that the flow was discharged to the left section of the compressor. In the case of model (d), the flow was discharged as a vent was determined at the lower section of the compressor. In addition, because the horizontal sections in Figures 17 and 18 were not a  
Figure 16: Velocity plots of vertical section at \(-20\) mm position from the center—front view. Figure 15: Velocity plots of vertical section at +40 mm position from the center—front view. normal symmetry but an axial symmetry, the sign of + to the horizontal center of the cooling fan and the--sign inside the MCR can be considered as the flow to the CBM. Figure 19 and Table 3 represents a mass flow rate for the original and modified CBMs. Models 1 and 2 CBMs showed a high mass flow rate as the vent was generated at the left side of the compressor, and Model 3 CBM showed a high mass flow rate at the section of the compressor. Thus, it can be considered that the flow around the compressor is actively generated when compared to that of the existing models. Figure 17: Velocity plots of horizontal section at +20 mm position from the center—top view. Figure 18: Velocity plots of horizontal section at \(-40\) mm position from the center—top view. Since the modified models represented more smooth flows around the compressor when compared with the existing models, the decrease in the temperature at the compressor could be estimated. The temperature of the compressor and condenser installed inside the MCR for the original model was 54.5 \({}^{\circ}\)C and 43.5 \({}^{\circ}\)C, respectively. The temperature of the compressor and condenser for the improved model 3 were 52.0 \({}^{\circ}\)C and 42.7 \({}^{\circ}\)C, respectively. The temperature of the modified model 3 showed a decrease of about 2.5 \({}^{\circ}\)C and 0.8 \({}^{\circ}\)C at the compressor and condenser, respectively.