Beitr. Tabakforsch. Int./Contrib. Tob. Research, 2001, 19-4, p. 189-203., ISSN.0173-783X

A mathematical scheme for calculating flows and pressure drops in lit and unlit cigarettes

Philip Morris USA, Research Center, Richmond, VA, USA
A computational methodology is presented for evaluating the flows and pressure drops in both lit and unlit cigarettes. The flows and pressure drops across rows of tipping-paper perforations are considered explicitly, as are the locations and relative sizes of the ventilation holes. The flows and pressure drops across air-permeable cigarette papers are included. The influence of plugwrap permeabilities on filter ventilation is developed. Lit cigarettes are mimicked by adding a "coal" pressure drop to the upstream end of the cigarette. The computational scheme is used to predict the effects of tobacco-rod length, puff volume, and vent blocking on cigarette ventilation and pressure drop. A derivation of the pressure-drop and flow equations for a cigarette with an upstream pressure drop is included in an appendix.