SPLITTING CHARACTERISTICS AND FLOW DISTRIBUTION OF GAS-LIQUID FLOW IN TWO PARALLEL PIPES

A model was developed to predict the onset of gas entrainment in a single downward oriented branch. The branch was installed on a horizontal square cross-sectional channel having a smooth stratified co-currently flowing gas-liquid regime in the inlet region. The branch flow was simulated as a three-dimensional point-sink while the run flow was treated as a uniform velocity at the critical dip. Experiments were performed to determine the critical liquid flow distribution between the run and the branch. A correlation was developed relating the branch Froude number to the ratio of the superficial liquid mass fluxes in the run and the branch. The correlation was used as a boundary condition in the model. A methodology was developed using digital imaging to record the coordinates of the critical dip at the onset of as entrainment. The dip angle was found to range between 40 to 60 degrees and constant dip angles of 40, 50 and 60 degrees were selected as boundary conditions. The critical height was predicted to within 50% of experiments with the error attributed to differences in the modeled and experimental geometries. A semi-empirical analysis using the experimental geometry yielded a critical height prediction to within 20% of experimental results.

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Experimental investigation on gas‐liquid flow distribution in downward parallel pipes of a 660 MW ultrasupercritical CFB boiler

International Journal of Energy Research ◽

10.1002/er.6258 ◽

2020 ◽

Author(s):

Yafei Xin ◽

Tiantian Niu ◽

Yinlong Li ◽

Dong Yang

Keyword(s):

Experimental Investigation ◽

Liquid Flow ◽

Flow Distribution ◽

Cfb Boiler ◽

Gas Liquid Flow

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Study on Gas-Liquid Two-Phase Flow Distribution Inside a Flute Header

ASME 2020 Power Conference ◽

10.1115/power2020-16710 ◽

2020 ◽

Author(s):

Liping Pang ◽

Shangmin Li ◽

Hu Yuan ◽

Liqiang Duan

Keyword(s):

Liquid Phase ◽

Gas Phase ◽

Liquid Flow ◽

Two Phase Flow ◽

Phase Distribution ◽

Flow Distribution ◽

Phase Flow ◽

Two Phase ◽

Parallel Channels ◽

Gas Liquid Flow

Abstract When the supercritical boiler is working at low load during flexible operation, the uneven distribution of the gas-liquid flow at the intermediate header may affect the safety of the water-cooled wall at the vertical parallel panels. In order to improve the uniformity of gas-liquid flow distribution in the water-cooled wall of intermediate header and study the internal flow mechanism, a flute inside the header is applied with parallel vertical parallel channels and experiments under different operating conditions are conducted to verify the effectiveness of this geometrical structure. The flow pattern in the experiment belongs to stratified and wavy flow. Computational fluid dynamic (CFD) simulation is conducted in order to investigate two-phase flow distribution behavior inside a flute header. It was found that the radial gas phase distribution in the flute tube shows a symmetrical relationship, and there are two vortexes in opposite directions. With the increasing distance from the inlet, the uniformity of the gas phase distribution becomes even. The gravity is greater than the drag force, which has effect on the two-phase flow distribution. The gas phase velocity has been improved inside flute section and liquid phase flow has more even flow distribution along annular section. It makes liquid phase sent to far end of flute header. That benefits two-phase flow distribution along 10 parallel channels equally.

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GAS-LIQUID FLOW DISTRIBUTION UNIFORMITY PARAMETERS IN UPWARD MULTI-PASS COMPACT EVAPORATOR

Jurnal Teknologi ◽

10.11113/jt.v78.9755 ◽

2016 ◽

Vol 78 (10-3) ◽

Author(s):

Zuradzman Mohamad Razlan ◽

Hazry Desa ◽

Shahriman Abu Bakar ◽

Khairunizam Wan ◽

Ishak Ibrahim ◽

...

Keyword(s):

Liquid Flow ◽

Water Distribution ◽

Flow Distribution ◽

Stratified Flow ◽

Air Conditioner ◽

Air Velocity ◽

Inlet Condition ◽

Automobile Air Conditioner ◽

Distribution Uniformity ◽

Gas Liquid Flow

The gas-liquid flow distributions in multi-pass upward parallel channels that simulate the evaporator for the automobile air-conditioner system were examined experimentally. In this paper, the attentions are (1) To study the influences of the backpressure condition at the branch outlets and of the flow-inlet condition at the header entrance on the gas-liquid distributions to the branches, (2) To discover the most influenced parameter to the flow distribution uniformity by using design of experiment method. Experiments were conducted in an isothermal air-water flow system. The influence of the backpressure condition on the flow distributions changed depending on the flow-inlet condition. In the stratified-flow inlet, the backpressure condition was highly influential in both the air and water distributions, and the uniform water distribution that was ideal for the evaporators could not be achieved even if air was distributed uniformly to all branches. In the mist-flow inlet, the water distribution was insensitive to the backpressure conditions and its uniformity was improved in comparison with that in the stratified-flow inlet. The flow distribution uniformity for gas phase is influenced mostly by superficial air velocity, and the flow distribution uniformity of liquid phase is mostly influence by 2-way interaction of parameters which are flow pattern and superficial air velocity.

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