Effects of Varying Tobacco Rod Circumference on Cigarette's Dynamic Ventilation Rate and Combustion State During Machine Smoking

Cigarette ventilation characteristics are one of the important design factors that affect the combustion state and therefore smoke release. In order to study the changes of ventilation characteristics and the combustion state of cigarettes with different rod circumferences during smoking, a device was designed that could flexibly measure the different ventilation characteristics along the cigarette rod. The device was utilized to measure the changes of the total ventilation rate and filter ventilation rate of cigarettes with different rod circumference in both burned and unburned conditions. At the same time, a test method was implemented to measure the temperature of the combustion coal puff-by-puff during the smoking process. The relationship between ventilation and the combustion state was analyzed on a per-puff basis. The results show that with the decrease of the rod circumference from 24 mm to 20 mm and 17 mm, the total ventilation rate under burning conditions changed considerably compared with unburned conditions, increasing by 55.7%, 60.5% and 74.5% on average, respectively. The ventilation of the cigarette paper played a major role in regulating the ventilation during puffing. With the increase from 17 mm to 24 mm in circumference, the combustion efficiency of the tobacco decreased as indicated by a range of thermophysical parameters of the burning coal.