Akhmad Zidni Hudaya

Experimental investigation on the interfacial characteristics of stratified air-water two-phase flow in a horizontal pipe

The interfacial wave characteristics of stratified air-water two-phase flow in a horizontal pipe were experimentally investigated by using the flush-mounted constant electric current method (CECM) sensors. The experiments were conducted in a horizontal two-phase flow loop 9.5 m long (L) consisting of transparent acrylic pipe of 26 mm i.d. (D). To obtain the stratified flow pattern, the superficial gas and liquid velocities were set to 1.02 – 3.77 m/s and 0.016 – 0.92 m/s, respectively. Several interfacial wave patterns as described by several investigators were identified. The common parameters such as liquid hold-up, probability distribution function, wave velocity and wave frequency were investigated as the function of the liquid and gas flow rates. The interfacial curvature was calculated on the basis of the liquid hold-up data from the CECM sensors and the liquid film thickness data from the image processing technique in the previous work. As a result, it was found that the mean liquid hold-up decreas...

An improved algorithm of image processing technique for film thickness measurement in a horizontal stratified gas-liquid two-phase flow

Due to the importance of the two-phase flow researches for the industrial safety analysis, many researchers developed various methods and techniques to study the two-phase flow phenomena on the industrial cases, such as in the chemical, petroleum and nuclear industries cases. One of the developing methods and techniques is image processing technique. This technique is widely used in the two-phase flow researches due to the non-intrusive capability to process a lot of visualization data which are contain many complexities. Moreover, this technique allows to capture direct-visual information data of the flow which are difficult to be captured by other methods and techniques. The main objective of this paper is to present an improved algorithm of image processing technique from the preceding algorithm for the stratified flow cases. The present algorithm can measure the film thickness (hL) of stratified flow as well as the geometrical properties of the interfacial waves with lower processing time and random-a...

Experimental study on the characteristics of flow pattern transitions of air-water two-phase flow in a horizontal pipe

The two-phase flow application was commonly found in industrial processes, such as oil and gas production in wells, gas and oil pipelines, etc. The characteristic of two-phase flow had various aspects depending on its interfacial behaviour. The interfacial structures of air-water two-phase flow in a horizontal pipe were experimentally investigated by using visualization method with high speed camera. The experiments were conducted in a horizontal two-phase flow facility, total length 10 m pipe made from acrylic with 26 mm ID. To obtain the flow pattern, a total of 132 flow condition were observed. The superficial gas and liquid velocities were set to 0.31 m/s – 20 m/s and 0.016 m/s – 0.77 m/s, respectively.High Speed Camera observation successfully characterized and demonstrated two-phase flow regime in a horizontal pipe. Its also developed flow regime maps. Air-water two-phase flow is characterized by bubble breakup and coalescence in the transition from plug to slug flow. Interfacial instabilities form in stratified to wavy flow, then small waves, larger waves and the droplet entrainment in transition to annular flow. High amplitude wave was required to form the slug flow. This flow pattern maps is a two-phase flow regime transition including stratified flow, plug flow, slug flow, annular flow and sub-regime of each patterns. The influence of superficial velocity of air and water has a significant effect on the flow patterns and sub-regime types.The two-phase flow application was commonly found in industrial processes, such as oil and gas production in wells, gas and oil pipelines, etc. The characteristic of two-phase flow had various aspects depending on its interfacial behaviour. The interfacial structures of air-water two-phase flow in a horizontal pipe were experimentally investigated by using visualization method with high speed camera. The experiments were conducted in a horizontal two-phase flow facility, total length 10 m pipe made from acrylic with 26 mm ID. To obtain the flow pattern, a total of 132 flow condition were observed. The superficial gas and liquid velocities were set to 0.31 m/s – 20 m/s and 0.016 m/s – 0.77 m/s, respectively.High Speed Camera observation successfully characterized and demonstrated two-phase flow regime in a horizontal pipe. Its also developed flow regime maps. Air-water two-phase flow is characterized by bubble breakup and coalescence in the transition from plug to slug flow. Interfacial instabilities form ...

The characteristics of the pressure gradient air-water stratified two-phase flow in horizontal pipes

The co-current air-water two-phase stratified flow is desired to occur in the application of pipelines system, such as natural gas gathering, long distance pipelines, and transmission pipelines, because this flow characteristics offers some advantages related to the safety factor of operational condition. The characteristics of pressure drop in stratified flow is considered as one of an important factor in the capital and operation costs for the simultaneous transportation of gas and liquid in various industries. The main objective of this study is to examine the effect of gas and liquid superficial velocities, and pipes diameter on the characteristics of pressure drop air-water two-phase stratified flow. Experiment has been conducted in 26 and 16 mm i.d. acrylic horizontal pipe with length 9.5 m. Air-water flow was recorded 190 D from the inlet using high speed video camera, and pressure difference was measured between 180 D and 210 D from the inlet using validyne pressure transducer. The common parameters such as visualization, pressure gradient signal in time series, probability density function (PDF), and mean of pressure gradient was analyzed. As a result the effect of gas and liquid superficial velocity, and pipes diameter on the characteristics of pressure gradient can be understood.

Experimental study on interfacial friction factor of the air-water stratified two-phase flow in a horizontal pipe

The Liquid hold-up and the Interfacial Friction Factor on the Air-Water Stratified Two-Phase Flow in a Horizontal Pipe have been experimentally investigated using superficial gas and liquid velocity of 4 – 16 m/s and 0.02 to 0.1 m/s, respectively. The stratified flow is observed on the horizontal acrylic pipe with 26 mm inner diameter and 9 m length. This present work has utilized the various methods of observation: visual observation through high speed video camera, hold up measurement by using CECM, and pressure gradient analysis which is gathered from the Validyne pressure transducer. The pressure gradient and liquid hold-up signal are sent through amplifier than converted into digital signal by Analog to Digital Converter (ADC). As a result, the characteristics of stratified flow is successfully revealed. Furthermore, a new correlation for hold-up which is based on the gas and liquid superficial velocity, and Froude number is proposed. The R2 which reaches 0.971 and the small value of error band (around 30 %) shows that the proposed correlation produce a good performance. Similarly, a new correlation for interfacial friction factor is also proposed which is arranged as a function of liquid hold-up, gas, and liquid Reynolds number. It produces a satisfying performance which is proven by the high value of R2, 0.999. Moreover, the error band between the proposed correlation and the experimental data is quite small, around 5 % on most of all data.

Penentuan Sub-sub Daerah Aliran Stratified Udara-Air pada Pipa Horisontal Menggunakan Constant Electric Current Method (CECM)

ABSTRAK Visualisasi dan liquid hold-up aliran stratified udara-air pada pipa horizontal sebagai fungsi waktu (dia. dalam pipa 26,0 mm dan total panjang seksi uji 9,5 m) telah diteliti secara eksperimental. Pada penelitian ini, studi visualisasi dilakukan dari analisa data visual yang dihasilkan kamera video kecepatan tinggi dan perilaku tebal film aliran diteliti dengan mengukur liquid hold-up menggunakan Constant Electric Current Method (CECM). Prinsip dari metode ini didasarkan atas perbedaan konduktivitas pada cairan dan gas. Pada penelitian ini digunakan sensor CECM sebanyak 3 buah dengan jarak aksial antar sensor 215 mm. Hasil penelitian ini menunjukkan bahwa karakteristik gelombang antarmuka yang dihasilkan dari pemprosesan sinyal CECM dan studi visual dapat digunakan untuk menentukan sub-sub daerah aliran stratified . Peta pola aliran stratified Udara-Air pada Pipa Horisontal yang dihasilkan dari penelitian ini dipresentasikan dan dibandingkan dengan peta-peta yang ada dari penelitian-penelitian terdahulu. Kata Kunci : Sub-sub daerah aliran, aliran stratified, CECM, gelombang antarmuka