# Simulation Analysis and Experimental Study of the Cooker Hoods of High-Rise Residential Buildings
## 4 Results and Discussion
Although medium heat radiation, such as fumes and air, has an impact on the temperature rise, its influence is not greatly changed by the air flow, so it is not significantly influenced by whether the window is closed or not. The results shown in Figures 11 and 12 also prove that the farther it is away from the pan, the lower the temperature. The highest temperature point is near the oil pan, with the highest temperature when the oil fumes are generated from the pan, and the temperature gradually decreases as the oil fumes rise. In the convection movement, the temperature in the kitchen is increased, and the temperature of the kitchen is higher closer to the roof, which is completely consistent with the actual situation, and the correctness of the simulation calculation method is also verified. The concentration field of oil fumes at the two entry boundaries was analyzed and calculated by a multicomponent simulation method. The oil fumes were divided into three groups: acetaldehyde, acetic acid, and water vapor. The concentration fields of acetaldehyde, acetic acid, and water vapor on the transverse section and longitudinal section are shown in Figures 13 and 14. It can also be seen from the above analysis that the oil fumes in the pan were not completely discharged by the cooker hood, and part of the oil fumes escaped from the upper right side to diffuse into the kitchen space. Due to the temperature of the oil fumes being higher compared with the surrounding air, it mainly concentrates on the kitchen roof as the air rises. This is the reason that the fumes' concentration near the kitchen roof is obviously higher than the bottom in the simulation calculation results. The maximum concentration of escaping fumes on the right and front side of the cooker hood is shown in Table 1.  
Figure 11: Exterior flow field temperature distribution of cooker hood (transverse section). under the window conditions of: (**a**) open and (**b**) close. Figure 12: Exterior flow field temperature distribution of cooker hood (longitudinal section) under the window conditions of: (**a**) open and (**b**) close. Figure 14: _Cont._  
Figure 13: The concentration field of oil fumes (transverse section) as the window conditions of: (**a**) open and (**b**) close when acetaldehyde, (**c**) open and (**d**) close when acetic acid and (**e**) open and (**f**) close water when vapor. In addition, it can be seen from the calculation results that the concentration of the oil fumes far away from the oil pan is relatively low on the section, and the phenomenon is reflected more clearly in the simulation results on the transverse section. The streamline distributions of oil fumes on the transverse section and longitudinal section of the kitchen are shown in Figures 15 and 16. It shows that the air flow is blocked when the window is closed, and the airflow supply to the kitchen with cooker hood is no longer from bottom to top, but rather shows a tendency to be replenished from the periphery and the flow instability. The movement of the air flow changes, which leads to diffusion and escape of soot. This is the main reason that the fumes' exhaust is not smooth and escapes more when the window is closed. Figures 17 and 18 show the simulation results of the velocity field on the transverse section and the longitudinal section. The velocity of the region above the cooker hood is smaller than the surrounding region, but the region is bigger. This indicates that the velocity of oil fumes that spreads to the rest of the kitchen was smaller when the fumes escaped into this region, and it verifies the analysis results of concentration field and streamline field of oil fumes: The oil fumes escaped more easily to this region through the right and front region of the cooker hood. Therefore, the escaped fumes can easily concentrate in this region, and this is also the main reason for the high temperature and fumes concentrations in the region. By contrast, this trend is more serious when the window is closed.