Surface tension effect on stability of two-phase stratified flow

Abstract

In this paper, the effect of wavelength on the disturbed interface of a two-phase stratified regime will be discussed. It is assumed that the two phases are completely separated and are flowing parallel to each other along the duct. In order to analyze the stability of the two-phase stratified flow, a small disturbance is considered at the interface. Growth or decline of the interface disturbance, relative velocity and surface tension in time will be discussed analytically and numerically. Numerical analysis is applied using the finite difference method. The results of the numerical method are compared with the analytical results of prior investigators. The results of the present paper show that the non-linear conservation equations model discussed is capable of predicting two-phase stratified flow behavior. The surface tension increases the physics of the model and has a positive effect on the convergence of the numerical result of the two-phase flow model. The convergence of the numerical results was obtained and is presented in the results section of the paper. This conclusion is unique to this paper and the Ransom and Hicks model [

Two‐dimensional modeling for stability analysis of two‐phase stratified flow

“…In the previous work, [3] at each section, the pressure average for liquid and gas flow was calculated. Although this simplification leads to a straightforward simulation of the flow field and results in overall estimation of interface shape, but it cannot evaluate the instability condition and onset of slug formation as exactly as required.…”

“…With time, the height of interface with respect to duct length, which is hereafter termed (x), decreased until it approaches to zero. The most important advantages of two-dimensional solution with respect to one-dimensional modeling considered here [3] is that one can trace the interface shape from onset of damping to full dissipation state. However, in one-dimensional modeling, only the onset of damping or growth of perturbation can be perceived.…”