Validation of numerical simulations of gas-liquid systems in a vertical pipe

Numerical simulations of gas-liquid two phase flow in a vertical pipe are performed using a commercial CFD code Star-CCM+. Two systems investigated in this study are air-water and air-silicone oil. The choice of silicone oil system can be attributed to its physical properties particularly surface tension being closer to the fluids used in industrial applications. The diameter of the pipe studied is 67 mm and the length is 6m. The results were validated against the experimental data from Szalinski etal. [1]. In this study Sγ model which is based on the method of moments was used to predict the bubble size distribution by accounting for coalescence and break-up. Simulations were performed with and without using Sγ model. It was seen that size distribution modeling had a huge impact on predicted results for void fraction distribution. Reasonably good agreements were obtained with Sγ model for both the two phase systems investigated. Two different drag models from Tomiyama and Bozanno-Dente were used in this study and it was seen that predictions from both were similar.