Study Of Temperature Characteristics Of Heating Process Of Low Temperature Cigarettes

As one of the tobacco products with the most rapid development in recent years,low temperature cigarette produce smoke by heating cigarettes instead of burning.Therefore,the content of harmful substances is much lower than that of traditional combustion cigarettes,and it can still maintain a good suction taste,so it is favored by consumers all over the world.The heating element is an important part of the low temperature cigarette heater.The quality of the heating effect directly affects the composition and taste of the smoke.At present,in the tobacco industry,the design of low temperature cigarette heaters is mainly based on experience,and the heat transfer research specifically for the low temperature cigarette heating process is still relatively rare.Because of the low thermal conductivity of tobacco,the temperature uniformity is poor when the traditional rod-shaped and sheet-shaped heating elements are used to heat the cigarettes,and the temperature in the internal area is easy to be too high,which is not conducive to reducing the harmful components of the smoke.Based on a low temperature cigarette heater heated by fuel combustion,with the help of numerical simulation software FLUENT,the temperature characteristics such as the heating rate and temperature uniformity of low temperature cigarette were analyzed.This thesis is mainly expanded according to the following two parts:The first part is aim at the most widely used rod-shaped heating element,and the influence of the diameter and material of the rod-shaped heating element on the temperature characteristics of cigarettes is investigated.The results show that the diameter of the rod-shaped heating element can significantly affect the heating effect of cigarettes.When a smaller diameter rod-shaped heating element is used for heating,the heating rate of the low temperature cigarette is rapidly increased,but the temperature uniformity is greatly reduced.In addition,the material selected for the heating structure will also affect the heating effect of cigarettes.When the volume heat capacity of the selected material is small and the heat diffusion coefficient is large,a good balance can be obtained in the preheating speed and temperature uniformity.In the second part,the comprehensive heating effect of the cross-shaped heating element and ring-shaped heating element on cigarettes was studied.The results show that compared with the traditional rod-shaped and sheet-shaped heating elements,both the cross-shaped and ring-shaped heating elements can greatly improve the temperature uniformity of cigarettes,but the heating rate of cigarettes decreases accordingly.Through the research of the ring-shaped heating element,it can be found that the position of the heating element can significantly affect the temperature uniformity and heating speed of low temperature cigarette.When the heating element is near the middle of the cigarettes radius,the thickness of heat conduction can be reduced,thus reducing the temperature difference of the cigarette section and improving the temperature uniformity.In addition,when the cross-shaped and ring-shaped heating elements use variable power heating strategies to heat cigarettes,not only the preheating time of low temperature cigarette can be significantly shortened,but also the temperature uniformity of the cigarettes can be improved to a certain extent.