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Experimental series of stratified gas-liquid two-phase flows had been carried out in a 26 mm i.d. transparent acrylic horizontal pipe. The study was aimed to determine the interfacial wave characteristics of the flow and to develop a high quality database of it. The longitudinal section of the pipe was used as the reference section of image recording. Air and water were used as the test fluids, flowing co-currently inside the pipe. The flow behavior was recorded by using a high-speed video camera around 5 m in axial distance from the inlet pipe to ensure the fully-developed stratified gas-liquid two-phase flow. To correct the refraction due to the acrylic pipe, a correction box was employed in the visualization test section. The group of stratified smooth and wavy two-phase flows were successfully recorded and classified on the basis of the visualization study from 24 couples of test condition of superficial water and air velocities. Digital image processing technique was then used to perform quantitative analysis and the results were used to evaluate the existing data. In the present study, the image processing technique was performed to obtain the liquid holdup distribution. The present results show satisfactory agreement with previous works., Comment: Proceedings of the 10th International Forum on Strategic Technology (IFOST 2015), 3 - 5 June 2015, Bali, Indonesia

In the chemical, petroleum and nuclear industries, pipelines are often used to transport fluids from one process site to another one. The understanding of the fluids behavior inside the pipelines is the most important consideration for the engineers and scientists. From the previous studies, there are several two-phase flow patterns in horizontal pipe. One of them is stratified flow pattern, which is characterized by the liquid flowing along the bottom of the pipe and the gas moving above it cocurrently. Another flow patterns are slug and plug flow patterns. This kind of flow triggers the damage in pipelines, such as corrosion, abrasion, and blasting pipe. Therefore, slug and plug flow patterns are undesirable in pipelines, and the flow is maintained at the stratified flow condition for safety reason. In this paper, the analytical-based study on the experiment of the stratified flow pattern in a 26 mm i.d. horizontal pipe is presented. The experiment is performed to develop a high quality database of the stratified two-phase flow pattern. The experimental data were obtained from the visualization data by using a high speed-video camera and were processed by using digital image processing technique. Analytical method of two-fluid model was used to study the interfacial behavior of the flow. The aim of this study is to validate the previous correlations which are proposed by other researchers. The results show that there are still many significant differences among each other. Hence, better correlation should be proposed in the future. The discussion on the basis of the comparison between the previous correlations with the present analytical data is presented., Comment: Proceedings of the Seminar Nasional Perkembangan Riset dan Teknologi di Bidang Industri ke-20, 23 May 2014, Universitas Gadjah Mada, Yogyakarta, Indonesia

Recently, experimental series of co-current gas-liquid upward bubbly flows in a 6 m-height and 54.8 mm i.d. vertical titanium pipe had been conducted at the TOPFLOW thermal hydraulic test facility, Helmholtz-Zentrum Dresden-Rossendorf, Germany. The experiments were initially performed to develop a high quality database of two-phase flows as well as to validate new CFD models. An ultrafast dual-layer electron beam X-ray tomography, named ROFEX, was used as measurement system with high spatial and temporal resolutions. The gathered cross sectional grey value image results from the tomography scanning were reconstructed, segmented and evaluated to acquire gas bubble parameters for instance bubble position, size and holdup. To assign the correct paired bubbles from both measurement layers, a bubble pair algorithm was implemented on the basis of the highest probability values of bubbles in position, volume and velocity. Hereinafter, the individual characteristics of bubbles were calculated include instantaneous three dimensional bubble velocities, Sauter mean diameters and the movement angle in polar-azimuthal directions. The instantaneous three dimensional bubble velocities are discussed through the distribution results of the axial, horizontal, radial and azimuthal velocities in statistical parameters. The present results show satisfactory agreement with previous works., Comment: Proceedings of the 1st International Conference on Engineering Technology and Industrial Application (ICETIA 2014), 4 December 2014, Universitas Muhammadiyah Surakarta, Surakarta, Indonesia