Transport Process of Virus Concentration from Airway to Cerebral Artery by using Computational Fluid Dynamics

When a person infected with the virus releases aerosol including the virus by sneezing or talking, the virus stays in atmosphere for a long time. If other persons inhale the virus, the person maybe infected. In our previous researches, in order to decrease efficiently the risk of infection, various indoor ventilation conditions have been evaluated by analysing transport process of the virus concentration using Computational Fluid Dynamics (CFD). From them, it was found that indoor ventilation condition can be optimised by evaluating amount of the virus concentration and residence time. However, the infection process in air way and vascular when these airborne viruses from indoor air is inhaled has not been elucidated yet. In this research, a couple analysis from nasal cavity to cerebral artery via organ is tried to be applied in order to analyse the transport process of virus concentration from nasal cavity to cerebral artery. In addition, the effect of breathing waveforms and virus proliferation on the virus infection is evaluated. Regarding the methods, 3D CAD model of these three parts is created. Continuity equation, Navier-Stokes equation and transport equations of virus concentration was used as the governing equations. The transport equations in the organ are modified with the virus proliferation. Inlet boundary conditions in the nasal cavity are set up to be four types of breathing waveforms. A boundary condition between the nasal cavity and the organ is continuity of virus concentration at the contact surface. Similarly, the other boundary condition between the organ and the cerebral artery is continuity of virus concentration. As results, it was found that the virus concentration in the cerebral artery in case of sinusoidal breathing waveform with long period is the smallest. It was also found that the virus concentration in the organ and the cerebral artery in case of proliferation within the organ is higher than that has no proliferations. It is concluded that a method for minimalizing risk of virus infection can be proposed by the couple analysis.