Air flow characterization within a cigarette using a permeability meter
The behavior of a cigarette, during a puff, is strongly determined by the air flow distribution inside. In order to better understand this behavior, a theoretical model has been used which is able to predict the pressure drop as well as the paper and tipping paper ventilation. This model needs to take into account several parameters which influence the flow rate and the pressure drop: cigarette and filter size, paper permeability, coefficients related to the laminar or turbulent airflow within the tobacco rod, the filter and the tipping paper. Whereas the cigarette sizes can be easily measured, the determination of the other parameters related to the air flow behavior is quite more difficult. In order to make this characterization easier, a permeability-meter commonly used for the paper permeability measurement has been modified. These modifications allow to carry out a quick and easy measurement of the pressure drop versus the flow rate within tobacco rods, filters and tipping paper.- Measurements within an encapsulated tobacco or filter rod allow us to calculate the coefficients related to the laminar or turbulent air flow properties.- Measurements within an obstructed ventilated filter rod allow us to calculate the coefficients related to the laminar and turbulent air flow within the ventilation zone. By using the previous determined parameters, we have been able to predict accurately both ventilation and pressure drop after a virtual assembling of a ventilated filter to a tobacco rod.