Numerical Simulation Of Internal Flow In Several Tobacco-Specific Standard Components

Abstract:The draw resistance standard rod, critical flow orifice (CFO) and non-linear air permeability standard are standard devices which are used to calibrate measuring instruments for the determination of draw resistance of cigarettes and pressure drop of cigarette filter rods. In many cases, the experimental study is difficult to carry out because of limited conditions. Therefore, in order to analysis the effects of ambient conditions on the metrological characteristics of the three kinds of tobacco testing standard devices, CFD is used to simulate the internal flow field under a series of different environmental factors. When the experimental conditions are allowed, the numerical data can be compared with the theoretical derivation and experimental results. Otherwise, the simulation data can be used to predict the result of environmental influences. The full contents include three main parts:(1) The draw resistance standard rod is a standard device which is used to test the draw resistance tester. In this paper, ten parallel capillary tubes are distributed in the rod. To control the passage under a volume gas flow rate of 17.5 ml/s, a series of numerical simulations have been carried out to simulate the internal flow field under a series of different environmental factors, the obtained pressure drop curves and corresponding formulas are given. The comparison indicates that the numerical simulation results agree with that of experiments very well.(2) The critical flow orifice (CFO) is a standard device can maintain a constant gas flow. In order to analysis the effects of ambient conditions on the front end of CFO, CFD is used to simulate the internal flow field under a series of different environmental factors. The influence curves are consistent with the results of other researchers'.(3) Air permeability standard is standard device used to measure tobacco-specific permeability, which can be divided into two types:non-linear air permeability standard and linear air permeability standard. In this paper, the relationship between environmental factors and volume flow during the use of non-linear air permeability standard has been studied by CFD. The relational expression obtained is consistent with experimental results.