Shokri - PhD Student of mechanical engineering, Tarbiat Modares University
Azimi - PhD Student of chemical engineering, Tarbiat Modares University
Ghiasi - PhD Student of mechanical engineering, Tarbiat Modares University
Ansari - Associate Professor, mechanical engineering, Tarbiat Modares University

In this article, transient condition of two-phase stratified gas-liquid flow was investigated using numerical simulation. The base of the method is including one-space dimensional transient solution of the governing equations using two-fluid model. In the present work, we use an analogy between the SIMPLE algorithm in two-space dimensional single phase flow and one-space dimensional two-phase stratified flow by applying special algorithm to solve the conservation equations. As modeling established and justified, wave growth was studied in two-phase stratified flow in a horizontal duct. The results obtained from this work were compared with the results of the previously published articles. The results show that the classical criterion for the Kelvin-Helmholtz (K-H) instability agrees when the long wavelength with small amplitude is considered. In this case, K-H instability criterion, wavelength effect on this instability and pressure variation on the two phases interface agreed well with the other researcher correlations. However, as wavelengths decreased, the results showed that the K-H instability criterion is over-predicted and is required to be modified.

two-phase stratified flow, two-fluid model, Kelvin-Helmholtz instability, SIMPLE algorithm, wavelength