Prediction of Transient Behaviors of Gas-Condensate Two-Phase Flow in Pipelines With Low Liquid Loading

2006 ◽  
Author(s):  
Daoming Deng ◽  
Jing Gong
Keyword(s):  
Flow Rate ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Flow Simulation ◽  
Gas Condensate ◽  
Phase Flow ◽  
Liquid Loading ◽  
Long Distance ◽  
Two Phase

Transporting natural gas and gas condensate in a long distance pipeline occurs frequently during the development of offshore or desert gas condensate and/or oil fields. However, the thermohydraulic calculation of gas-condensate pipeline, especially transient flow simulation, is hitherto a challenging issue in the pipeline industry on account of a maze of complexities of pipeline undulation, changeable properties of fluid, and transfer of momentum, mass and heat. This study is intended to predict the transient flow behavior in gas-condensate pipelines. In the paper, a hydraulic and thermodynamic (such as phase behavior and properties) model for the analysis of transient gas-condensate two-phase flow in pipelines with low liquid loading is outlined. The hydraulic model is based on simplified “No Pressure Wave” model where the constitutive relation results from the Ottens et al (2001) correlation. An implicit method, the convergence and stability of which have been verified by example calculations, is utilized to solve the transient flow model equations of gas-condensate pipelines. In the end, the transient performances of low-liquid-loading gas-condensate two-phase non-isothermal flow in undulating pipelines, which are subjected to boundary conditions of increasing or decreasing inlet flow rate and specified outlet pressure with time, are numerically investigated. The results, such as pressure and liquid holdup profiles vs. time, and time evolutions of outlet condensate flow rate and accumulated liquid content etc., show that the presented model and numerical method for analyzing gas-condensate transient flow behaviors in pipelines looks reasonable.

Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration: (11) Bubble Motion Under the Flow Vibration

2014 ◽  
Author(s):  
Ryotaro Yokoyama ◽  
Jun-ichi Takano ◽  
Hideaki Monji ◽  
Akiko Kaneko ◽  
Yutaka Abe ◽  
...  
Keyword(s):  
Flow Rate ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Bubbly Flow ◽  
Plug Flow ◽  
Flow Simulation ◽  
Phase Flow ◽  
Bubble Behavior ◽  
Two Phase ◽  
Rate Fluctuation

Earthquake is one of the most serious phenomena for safety of a nuclear power plant. Therefore, nuclear reactors were contracted considering structural safety for a big earthquake. In a nuclear reactor, the gas-liquid two-phase flow is the one of primary factor of the property and bubbly or plug flow behavior is important issue to evaluate of safety. However, the influence of an earthquake vibration on the gas-liquid two-phase flow inside the nuclear power plant is not understood enough. For example, the bubbly flow behavior under the flow rate fluctuation caused by the earthquake acceleration is not clear. It is necessary to clear the two-phase flow behavior under the earthquake conditions. To develop the prediction technology of two-phase flow dynamics under the earthquake acceleration, the detailed two-phase flow simulation code with an advanced interface tracking method, TPFIT was expanded to the two-phase flow simulation under earthquake accelerating conditions. In the present study, the objective is to clarify the behavior of the gas-liquid two-phase flow under the earthquake conditions. Especially, the bubble behavior in the two-phase flow, a diameter, shape and velocity of bubbles which are expected to be influenced by the oscillation of the earthquake is investigated. In this experiment, the flow was bubbly flow and/or plug flow in a horizontal circular pipe. The working fluids were water and nitrogen gas. The nitrogen gas from gas cylinder was injected into the water through a nozzle and bubbly flow was generated at a mixer. The water was driven by a pump and the flow rate fluctuation was given by a reciprocating piston attached to the main flow loop. Main frequency of earthquakes is generally between 0.5Hz and 10Hz. Thus the frequency of the flow rate fluctuation in the experiment also was taken between 0.5Hz and 10Hz. The behavior of horizontal gas-liquid two-phase flow under the flow rate fluctuation was investigated by image processing using a high-speed video camera and PIV at test section. The pressure sensors were installed at the inlet of the mixer and the outlet of the test section. As the result, the bubble behavior mechanism under the flow rate fluctuation was obtained. In addition, the acceleration of a bubble and the pressure gradient in the pipe was synchronized under all frequency conditions. The prediction results by TPFIT were compared with the experimental results. They show good agreement on the flow field around a bubble and the bubble behavior.

Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration (6) Numerical Simulation of Bubble Deformation Near Wall Under Accelerating Condition

2012 ◽  
Author(s):  
Hiroyuki Yoshida ◽  
Taku Nagatake ◽  
Kazuyuki Takase ◽  
Akiko Kaneko ◽  
Hideaki Monji ◽  
...  
Keyword(s):  
Flow Rate ◽  
Nuclear Reactor ◽  
Two Phase Flow ◽  
Nuclear Reactors ◽  
Bubbly Flow ◽  
Flow Simulation ◽  
Structural Safety ◽  
Phase Flow ◽  
Two Phase ◽  
Safety Operation

Earthquake is one of the most serious phenomena for safety of a nuclear reactor in Japan. Therefore, structural safety of nuclear reactors has been studied and nuclear reactors were contracted with structural safety for a big earthquake. However, it is not enough for safety operation of nuclear reactors because thermal-fluid safety is not confirmed under the earthquake. For instance, behavior of gas-liquid two-phase flow is unknown under the earthquake conditions. Especially, fluctuation of void faction is an important factor for the safety operation of the nuclear reactor. In the previous work, fluctuation of void faction in bubbly flow was studied experimentally and theoretically to investigate the stability of the bubbly flow. In such studies, flow rate or void fraction fluctuations were given to the steady bubbly flow. In case of the earthquake, the fluctuation is not only the flow rate, but also body force on the two-phase flow and shear force through a pipe wall. Interactions of gas and liquid through their interface also act on the behavior of the two-phase flow. The fluctuation of the void fraction is not clear for such complicated situation under the earthquake. Therefore, the behavior of gas-liquid two-phase flow is investigated experimentally and numerically in a series of study. In this study, to develop the prediction technology of two-phase flow dynamics under earthquake acceleration, a detailed two-phase flow simulation code with an advanced interface tracking method TPFIT was expanded to two-phase flow simulation under earthquake conditions. In this paper, outline of expansion of the TPFIT to simulate detailed two-phase flow behavior under the earthquake condition was shown. And the bubbly flow in a horizontal pipe excited by oscillation acceleration and under the fluctuation of the liquid flow was simulated by using expanded TPFIT. Predicted deformation of bubbles near wall was compared with measured results under flow rate fluctuation and structural vibration.

Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration: 10 — Numerical Prediction of Velocity Profile Around Bubble Under Accelerating Condition

2013 ◽  
Author(s):  
Hiroyuki Yoshida ◽  
Taku Nagatake ◽  
Kazuyuki Takase ◽  
Akiko Kaneko ◽  
Hideaki Monji ◽  
...  
Keyword(s):  
Void Fraction ◽  
Flow Rate ◽  
Nuclear Reactor ◽  
Two Phase Flow ◽  
Nuclear Reactors ◽  
Bubbly Flow ◽  
Flow Simulation ◽  
Structural Safety ◽  
Phase Flow ◽  
Two Phase

An earthquake is one of the most serious phenomena for the safety of a nuclear reactor in Japan. Therefore, structural safety of nuclear reactors has been studied and nuclear reactors ware contracted with structural safety for a big earthquake. However, it is not enough for safety operation of nuclear reactors because thermal-fluid safety is not confirmed under the earthquake. For instance, behavior of gas-liquid two-phase flow is unknown under the earthquake conditions. Especially, fluctuation of void fraction is an important factor for the safety operation of the nuclear reactor. In the previous work, fluctuation of void faction in bubbly flow was studied experimentally and theoretically investigate the stability of the bubbly flow. In such studies, flow rate or void fraction fluctuations were given to the steady bubbly flow. In case of the earthquake, the fluctuation is not only the flow rate, but also a body force on the two-phase flow and shear force through the pipe wall. Interactions of gas and liquid through their interface also act on the behavior of the two-phase flow. The fluctuation of the void fraction is not clear for such complicated situation under the earthquake. Therefore, the behavior of gas-liquid two-phase flow is investigated experimentally and numerically in the series of study. In this study, to develop the predictive technology of two-phase flow dynamics under earthquake acceleration, a detailed two-phase flow simulation code with an advanced interface tracking method TPFIT was expanded to two-phase flow simulation under earthquake conditions. In this paper, the bubbly flow in a horizontal pipe excited by oscillation acceleration and under the fluctuation of the liquid flow was simulated by using the expanded TPFIT. Predicted time series of velocity profiles around the bubbles and shapes of bubbles were compared with measured results under flow rate fluctuation and structural vibration. Predicted results were almost same as measured results qualitatively. And it was concluded that the expanded TPFIT can be applied to qualitative analysis of bubbly flow under accelerating conditions.

Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration — (4) Measurement of Bubble Deformation Near Wall Under Flow Rate Fluctuation

2012 ◽  
Author(s):  
Satoshi Okachi ◽  
Masaki Seto ◽  
Hideaki Monji ◽  
Akiko Kaneko ◽  
Yutaka Abe ◽  
...  
Keyword(s):  
Flow Rate ◽  
Two Phase Flow ◽  
Pipe Wall ◽  
Flow Behavior ◽  
Plug Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Bubble Deformation ◽  
Rate Fluctuation

In order to clear the two-phase flow behavior under earthquake, a systematic study is done experimentally and numerically. The present study is one on the series of the study on two-phase flow under earthquake, and focuses on the flow rate fluctuation. The flow rate fluctuation was added to bubbly or plug flow in a horizontal pipe, and flow behavior was measured by PIV and image processing. The bubble deformation near the pipe wall was observed and the velocity field around the bubble was shown. The bubble coalescence was also observed under the flow rate fluctuation condition.

Numerical Study of the Single-Phase and Two-Phase Flow in a Centrifugal Pump

2013 ◽  
Vol 307 ◽  
pp. 215-218
Author(s):  
Te Ba ◽  
Arthur Teck Bin Lim ◽  
Chang Wei Kang
Keyword(s):  
Centrifugal Pump ◽  
Single Phase ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Flow Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Normal Mass ◽  
Phase Water

The paper presents the numerical investigation of a radial flow centrifugal pump with 2D curvature blade geometry. The geometry is based on the experimental equipment by Anagostopulos. Single phase (water) flow is modeled with a normal mass flow rate and rotation speed. Pressure distribution and fluid streamlines are evaluated and visualized. An extension of the model to transient flow and two-phase flow simulation has been done to see the effect of impeller rotation and gas entrainment in the centrifugal operation procedure.

Experimental Study of Low Liquid Loading Gas-Liquid Flow in Near-Horizontal Pipes

2003 ◽  
Vol 125 (4) ◽  
pp. 294-298 ◽  
Author(s):  
Nicolas R. Olive ◽  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Clifford L. Redus ◽  
James P. Brill
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Liquid Density ◽  
Phase Flow ◽  
Liquid Holdup ◽  
Liquid Loading ◽  
Two Phase ◽  
Horizontal Pipes

Gas-liquid two-phase flow exists extensively in the transportation of hydrocarbon fluids. A more precise prediction of liquid holdup in near-horizontal, wet-gas pipelines is needed in order to better predict pressure drop and size downstream processing facilities. The most important parameters are pipe geometry (pipe diameter and orientation), physical properties of the gas and liquid (density, viscosity and surface tension) and flow conditions (velocity, temperature and pressure). Stratified flow and annular flow are the two flow patterns observed most often in near-horizontal pipelines under low liquid loading conditions. Low liquid loading is commonly referred to as cases in which liquid loading is less than 1,100m3/MMm3 (200 bbl/MMscf). Low liquid loading gas-liquid two-phase flow at −1° downward pipe was studied for air-water flow in the present study. The measured parameters included gas flow rate, liquid flow rate, pressure, differential pressure, temperature, liquid holdup, pipe wetted perimeter, liquid film flow rate, droplet entrainment fraction and droplet deposition rate. A new phenomenon was observed with air-water flow at low superficial velocities and with a liquid loading larger than 600m3/MMm3. The liquid holdup increased as gas superficial velocity increased. In order to investigate the effects of the liquid properties on flow characteristics, the experimental results for air-water flow are compared with the results for air-oil flow provided by Meng. (1999, “Low Liquid Loading Gas-Liquid Two-Phase Flow In Near-Horizontal Pipes,” Ph.D. Dissertation, U. of Tulsa.)

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