Simulating the influence of exhaust hood position on ultrafine particles during a cooking process in the residential kitchen

Abstract

A large amount of ultrafine particles are produced while cooking that seriously endanger human health. This paper uses a computational fluid dynamics model to simulate interior space airflow in an oil-heating process with three exhaust hood positions. Based on the obtained airflow velocity and temperature distributions, combined with the drift flux model, we were able to predict the ultrafine particle distribution with three particle diameters. The results show that exhaust hood positions influence the effect of the air supplement, but do not significantly reduce the concentration of ultrafine particles. When the exhaust hood is placed facing the window, the air supplement improves the capture efficiency but exacerbates the diffusion of ultrafine particles. When placed away from the window and in a corner, the distribution of ultrafine particles in the kitchen is basically the same, but due to the air supplement, the temperature around the personnel at the corner position is effectively reduced. The results also show that the distribution of ultrafine particles can be attributed to the airflow velocity approaching the hood, and warmer supplementary air will cause them to diffuse easily into the surrounding environment. By comparing the particle distributions at 0.01, 0.05, and 0.1 µm particle diameter, it is found that the effect of particle dynamics on the diffusion of ultrafine particles is relatively slight in a limited space. When supplementary air comes from the door, the kitchen’s airflow pattern produces some effect as the displacement ventilation. Although the supplementary air from different hood positions have similar effects on the airflow characteristics in the cooking zone, they have different effects on the diffusion of ultrafine particles to the surrounding environment.