Reasearch On Diffusion Mechanism Of Cigarette Smoke From The Paper Wrapper

The effect of smoke on human health and indoor air quality have grown more and more public attention, which is one of the main pollutant emission in door, and there is lots of carcinogenic substances to threat people’s health except to upset the eyes, nose and throat. So the calculation fluid dynamics(CFD) technique and particle image velocimetry(PIV) measurement method were used to study the outward diffusion process of cigarette smoke through cigarette paper, meanwhile the processes of the cigarette smoke through the cigarette paper and from the burning end to the suction side through a tobacco, were explained in the paper. It also revealed the association mechanism of the cigarette structure and the emission process of mainstream smoke and side stream smoke, provided a new research method and new thinking for the cigarette smoke research process, which help tobacco researchers from the cigarette smoke better understand and control the cigarette structure, and is very important to improve the competitiveness of cigarette enterprises.On account of this, the main research includes the following:1. The self-development experimental smoke prototype machine was used to snap the smoke flow field by using PIV system. Based on it, the outward diffusion flow fields of cigarette smoke through cigarette paper were studied with different pressure. Some parameters of cigarette paper and tobacco were measured, including the porosity of cigarette paper ?, the average pore diameter of cigarette paperpD, the porosity of tobacco ?, which provided input parameters and the other boundary conditions for CFD simulation.2.By using the experimental smoke prototype, CO contents through the cigarette paper as marked products were measured and analyzed. With different frequency of the step motor, the smoke pressures from suction side were measured.3. Combustion characteristics of cigarette under different suction were finished by using the UDF program and dynamic grid implementation; As porous medium(porous media), viscous drag force coefficient ?1 and inertia force coefficient C of cigarette paper and tobacco were finished; In the basis of the above, component transport model of the laminar flow, SIMPLEC, pressure- based algorithm and second order upwind scheme in the FLUENT software, were used to simulate cigarette smoke in different smoking status, and the effects of cigarette paper porosity, average pore size, suction pressure on the CO content discharged from the outer wall of the cigarette paper, were discussed. To verify the model, gas discharge rate from the outlet was used to compare between the simulation results in Fluent software and PIV experimental measurements.Based on the above researches, the results show that:1. The self-development experimental smoke prototype machine can be finished to snap the smoke flow field by using PIV system, and can cooperate with other means to measure the input parameters for CFD simulation.2. Under different pressure on the suction side, smoke diffusion velocity of the burning end, and co content at measuring position of combusting cigarette paper increase as the suction pressure increases.3. When the porosity of cigarette paper is between 0.415-0.482,the effect on the content of the CO discharged from the outer wall of the cigarette paper is not obvious; the effectof CO discharged from the outer wall of the cigarette paper on the average pore diameter of the cigarette paper has certain influence, and CO emissionincrease with the increase of the average pore diameter of cigarette paper, and they present nonlinear variation; The effect of suction pressure on the CO discharged from the outer wall of the cigarette paper is larger, CO content increase with the increase of suction pressure.4. It is valid to simulate the smoke diffusion course with the different pressure by using component transport model of the laminar flow, SIMPLEC, pressure- based algorithm and second order upwind scheme in the FLUENT software.