| There is a strong correlation between temperature distribution in burning cone of cigarette and chemical emission in mainstream smoke, and the temperature distribution is greatly influenced by design parameter of cigarette. Cigarette paper and plug-wrap paper may influence temperature distribution and smoke transfer by gas diffusion and dilution during cigarette combustion. In the present work, effect of cigarette paper permeability and filter ventilation on gas diffusion, temperature distribution and CO delivery during cigarette combustion was studied, using apparatuses of ventilation and temperature distribution measurement. The relationship among gas diffusion, temperature distribution in burning core and CO yield was investigated systematically, to reveal the intrinsic influence of cigarette materials on cigarette combustion status and delivery of CO from smoke.(1) Study on the effects of cigarette material on ventilation airflow of cigarette rod in dynamic smoking conditions.An apparatus of ventilation was set up in bell-curve smoking condition, which reflected the real, dynamic smoking conditions. The determination methods of ventilation airflow were built under the three states(the whole cigarette rod/ the part cigarette rod/the remaining burning cone rod). The effects of ventilation airflow in the different cigarette materials were investigated in this work, which included the different cigarette paper permeability(30-70 CU), filter ventilation(50-700 CU) and the remaining cigarette rod(0-30 mm). The results are as following: The paper ventilation of cigarette is increased with the paper permeability increased. the paper ventilation can be reached 12% when the paper permeability is 70 CU(the degree of filter ventilation is zero); the filter ventilation are 0%-60% in dynamic smoking conditions, while the filter ventilation are 0%-51%in a constant air stream(GB/T22838.15-2009), the value of the former is greater than the latter; the paper ventilation is increased with increasing the remaining cigarette rod. The effects of the three states of cigarette on ventilation airflow follow the sequence of the whole cigarette> Cutting cigarette> Combustion cone.(2) Study on the effects of cigarette materials on temperature distribution in burning cone.The effect of cigarette material on temperature distribution in burning cone were studied, using the maximum temperature, burning cone volume and characteristic temperature as characteristic variables. During the smoldering state, the burning cone volume and characteristic temperature increased with the increase of paper permeability, but maximum temperature was not affected by increase of paper permeability; the maximum temperature, burning cone volume and characteristic temperature were not obviously affected by filter ventilation and length of cigarette rod. During smoking state, the temperature distribution of cigarette burning cone was significantly affected by filter ventilation, paper permeability and the length of cigarette rod. With the increase of filter ventilation, the maximum temperature and characteristic temperature decreased, the volume of middle and high temperature zone decreased, the volume of low temperature zone increased, and the volume total temperature zone decreased. With the cigarette rod becoming short, the maximum temperature, characteristic temperature and burning cone volume increased, but the volume of high temperature zone decreased. With the increase of paper permeability, the maximum temperature, characteristic temperature and burning cone volume increased, and there is a point of inflection at 60 CU(3) Study on effects of gas diffusion and temperature distribution of cigarette burning cone on CO yield.The relationship between CO yield and temperature distribution of cigarette burning cone was investigated, considering gas diffusion and dilution. The CO yield in combustion was greatly affected by temperature distribution. In low temperature range of 200-400 oC, CO yield increased with increase of volume of low temperature zone; while in the mild temperature range of 400-600 oC and high range above 600 oC, CO yield decreased with increase of volume of mild and high temperature zone. The correlation coefficients between CO yield and volume of low, mild, high temperature range were 0.9561,-0.9778 and-0.9994. And highly correlated linear regression equation was obtained, with the correlation coefficient of 0.9999, which provides technical support for prediction of CO yield in cigarette combustion cone. |
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