ラプラス変換法による管内振動流の軸方向ガス有効拡散係数の評価

抄録

Analysis of gas transport in oscillatory flow though an airway model with complex geometry such as a single bifurcation, relies on the theoretical understanding of gas exchange during High-frequency oscillation; HFO. Our purpose was to develop a method for measuring the mean effective diffusivity in an oscillatory flow between two points, by applying Laplace integration, and the Laplace parameter s are related to the accuracy of th measured effective diffusivity, D_eff. In this study, numerical analysis was carried out to investigate the Laplace Transform Method. We defined the parameter K required to obtain optimum s, and found that K≃0.1. Then we applied this method to evaluate D_eff in a straight tube and a single symmetrical bifurcation. The theoretical results for a straight tube agreed a factor of Dn²/α⁴, that proved the effect of the secondary flow.