CFD Simulation Of Microbe Particle Transmission And Control In HVAC System

Microbial pollution, as one of the reasons causing the SBS, attracts more and more people's attention. In building environment, VAC system is to provide a healthy and comfortable indoor environment for people. However, if the design, operation, and maintenance of VAC system are not proper, microbe will grow in the system. When they are transmitted into the room, they would pollute the indoor air and be bad to human's health. Research result indicates that the air even very low concentration, will be evident direct pertinence between the amount of outdoor air suspending granule and the amount of human sick and dead. The research result also indicates that, it is quantitatively the same of the mass concentration between the outdoor air and the air transported into the room. So it is very sensible to improve the design, operation and maintenance of the VAC system in order to control the microbe pollution.In VAC system, microbes attach to the dust particle mostly and form microbial particle adhere to the surface of duct. The paper analysis the forces and resuspension mode of multidisperse microbial particle in laminar sublayer and the resuspension model of multidisperse microbial particle is established based on the force/moment balance. The fraction of multidisperse microbial particle under different velocity on the surface of duct was calculated. As to the microbe particle imported from the inlet, use the Rosin-Rammler distribution, which can proper describe the concentration of the air particle. The CFD technology was used to simulate the movement of particle on duct surface and analysis the velocity effect on the supply air particle concentration.Increasing the ratio of the fresh air is widely accepted to improve the indoor air quality. Fresh air can bring in oxygen, dilute carbon dioxide, and eliminate peculiar smell. But as we all know, in recent years, the atmosphere was polluted seriously, the dusts and microbes adhere to them will be imported and aggravate the indoor air pollution. Hence, the VAC designer should consider how to control the amount of dusts and microbe particles at the mean time of increasing the fresh air ratio. In this paper, after the simulation of the indoor air quality under different air ratio, we can get that how to combine the filters can we make good use of them. The objective of research on the microbial contaminates and diffusion is to control pollution and decrease the adverse effect on people. In this paper, after contrast analysis we can get that microwave can kill the air microbes effectively, so in this paper, microwave air disinfector is developed. The kill ratio experiments of four bacteria were conducted. And through the unsteady CFD simulation of the device operation in a public space, we can see the microwave air disinfector can control the indoor air microbe concentration speed and effectively.