关于一维非定常气─固二相流特征理论的讨论

On the Characteristic Theory of One-Dimensional Unsteady Gas-Solid Two-Phase Flows

本文研究了一维非定常气－团二相流的特征，对于目前常用的、包含一定近似的运动方程组，它有两个虚部很小的复根，研究表明这种很小的虚部出现与方程中引入的近似有关。从十多个算例的结果看，这样的虚部不影响人们在工程计算中用该方程组求解初值问题。针对具有上述特征的气－团二相流方程组，本文发展了一种类特征线方法，它保留了双曲型方程特征线方法的若干优点，但它允许方程的特征根中有微小的虚部。含灰气体激波管流动的计算表明，类特征线法具有精度高。

The characteristics of the one-dimensional, unsteady gassolid two phase flows have been studied in this paper. For the usually used set of motion equations which includes some approximations, there are two complex eigenvalues with a very small imaginary part. It is showed that the appearance of the imaginary parts is related to the introduction of these approximations. In view of more than ten examples, such small imaginary parts do not influence solving the initial-value problems of the set of equations in engineering calculations.According to the set of equations of gas-particle flows possessing such characteristics, a quasi-characteristic method has been developed in this paper. It holds some advantages of he characteristic method, still allows very small imaginary parts exist in the eigenvalues. The completed calculations of the flows in a dust-gas shock tube show that the quasicharacteristic method has the advantages of high precision and small numerical dissipation and dispersion.