An investigation into the effects of breathing upon the aspiration efficiency of the human head

A mathematical investigation is undertaken into the effects of the breathing pattern upon the aspiration efficiency of the human head. It is assumed that all the fluid inhaled by the head is subsequently exhaled and that the two stages of the breathing pattern last for an equal length of time. The particles are taken to be spherical and are assumed to be suspended without sedimentation in an ideal fluid which is flowing towards the head. A model for the head is proposed and the case of breathing through the mouth is studied. An analytical approach is adopted to determine the behaviour of the particles near the mouth, and the sampling efficiency of the head is investigated. Results are obtained for various situations, and comparisons are made with existing experimental results. It is shown that, in many cases, the effect of the breathing pattern is insignificant but for normal human breathing rates, it becomes significant as the velocity of the flow increases.