Numerical simulation of cigarette smoking process
A comprehensive two-dimensional (2D) mathematical model was developed to simulate the process of cigarette smoking. The developed model features four characteristics: (1) adopting kinetic models for water evaporation, tobacco pyrolysis and char oxidation; (2) applying the mathematical relationships between the release amounts of certain products (i.e. tar and CO) and different reaction variables (i.e. temperatures and oxygen concentrations); (3) introducing the transfer of mass, energy and momentum; (4) considering the filtration effect of cigarette filter to tar. The said characteristics are expressed through a set of simultaneous equations that can be numerically solved by Fluent software. The temperature field, char density field, flow velocity field in cigarettes during smoking, the CO and tar density fields in mainstream smoke and the filtration efficiency of filter to tar were simulated via the model. The model was validated by comparing the predicted values of site-specific temperature in cigarettes, puff number, filtration efficiency, CO and tar release with the corresponding experimental data. The results showed that the predicted values correspond well with the experimental data, for example, the predicted puff number was 7 and the experimental one was 6.2. The relative deviations between the predicted and experimental values of the site-specific temperature, CO release, tar release and filtration efficiency are <18 %, 6.4 %, 1.8 % and 3.4 %, respectively.