scholarly journals Study on Two-Phase Mixing inside Flow Focusing/Blurring Nozzle by Gray Distribution Analysis Method

2021 ◽  
Vol 11 (14) ◽  
pp. 6260
Author(s):  
Jin Zhao ◽  
Zhi Ning ◽  
Ming Lü ◽  
Chunhua Sun
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Water Flow Rate ◽  
Orifice Diameter ◽  
Inertia Force ◽  
Distribution Analysis ◽  
Flow Focusing ◽  
Two Phase ◽  
Phase Mixing ◽  
Gas Liquid Flow

The application prospect of a flow focusing/blurring nozzle is broad but research on gas-liquid flow inside the nozzle is not comprehensive. The gas-liquid mixing inside the nozzle is difficult to study by visualization experiment, so this paper proposes to study the gas-liquid flow or mixing inside the nozzle by the gray scale level distribution of the experimental images. The results show that the increase of air flow rate is beneficial to two-phase mixing inside the nozzle, while the influence of water flow rate, tube hole distance (the distance between inner tube and nozzle outlet) and orifice diameter increase is opposite. The influence of air inertia force on two-phase mixing is weaker than the water inertia force under different parameters, the effect of the air inertia force on two-phase mixing is similar to tube hole distance under a small flow rate, the effect of the orifice diameter on two-phase mixing is relatively weak. In addition, the analysis of the gas-liquid flow field in the mixing zone shows that the gas-liquid flow in the nozzle is stable in the flow focusing mode. In the flow blurring mode, the gas-liquid flow inside the nozzle has radial stability but axial pulsation. In the transition mode, the gas-liquid flow inside the nozzle is unstable, but the gas-liquid flow is close to the flow blurring mode.

Experimental Investigation of the Two-Phase Phenomena in a Small Discharge Installed on a Large Pipe With Stratified Gas-Liquid Flow

2009 ◽  
Author(s):  
Robert Bowden ◽  
Wael F. Saleh ◽  
Ibrahim Hassan
Keyword(s):  
Experimental Investigation ◽  
Flow Visualization ◽  
Flow Rate ◽  
Liquid Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Gas Entrainment ◽  
Small Discharge ◽  
Gas Liquid Flow ◽  
Good Agreement

Experiments were performed in a 50.8 mm diameter horizontal pipe with co-current stratified gas-liquid flow. A single, 6.35 mm diameter, downward oriented discharge was located at 1829 mm from the horizontal pipe’s inlet. Water and air, operating at a pressure of 312 kPa and adiabatic conditions, were used. The objectives of the study were to investigate gas entrainment in the discharge branch. Qualitative flow visualization of the two-phase entrainment flow structure was conducted, and measurements of the critical liquid height, two-phase mass flow rate, and quality, are provided. The results were compared with available correlations and showed good agreement with selected models.

Co-Current Stratified Gas-Liquid Flow in a Horizontal Pipe With Discharging Branches

2009 ◽  
Author(s):  
Robert Bowden ◽  
Wael F. Saleh ◽  
Ibrahim Hassan
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Test Section ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Phase Measurements ◽  
Single Discharge ◽  
Gas Liquid Flow ◽  
Pipe Inlet ◽  
Two Fluid

Experiments were performed in an adiabatic horizontal pipe with co-current stratified gas-liquid flow and a single discharge oriented at either 0, 45, or 90 degrees from horizontal. The study used air and water as the two fluid phases, operating at 312 kPa. The test section was scaled down from a typical CANDU header-feeder bank and used a pipe and discharge diameter of 50.8 mm and 6.35 mm, respectively. The objectives of the study were to provide quantitative two-phase measurements of the mass flow rate and quality at the pipe inlet, outlet, and discharge branch.

Mucus clearance by two-phase gas-liquid flow mechanism: asymmetric periodic flow model

1987 ◽  
Vol 62 (3) ◽  
pp. 959-971 ◽  
Author(s):  
C. S. Kim ◽  
A. J. Iglesias ◽  
M. A. Sackner
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Flow Model ◽  
Horizontal Tube ◽  
Tube Model ◽  
Flow Mechanism ◽  
Inspiratory Flow Rate ◽  
Two Phase ◽  
Mucus Clearance ◽  
Gas Liquid Flow

Mucus transport by two-phase gas-liquid flow mechanism was investigated with in vitro flow models under asymmetric periodic airflow conditions with nine different liquid solutions with rheological properties similar to human sputum. The flow model was made with 1.0-cm-ID glass tube and positioned either vertically or horizontally. With a constant supply of the test liquids into the model tube (0.5 ml/min), the liquid layer transport speed (LLTS) as well as the mean liquid layer thickness at steady-state condition (hs) was measured in conjunction with various airflow patterns of different expiratory and inspiratory flow rate, breathing frequency (f), and tidal volume (VT). The flow patterns were maintained within the range of normal breathing. In the horizontal tube model, LLTS ranged from 1.14 +/- 0.02 to 3.39 +/- 0.04 cm/min at the peak expiratory flow rate (VEp) of 30–60 l/min. The inspiratory flow rate, as well as f and VT did not affect LLTS. However, LLTS increased with increasing VEp, and at the same VEp LLTS was higher with viscoelastic than with viscous liquid. In the vertical tube model, the upward transport of mucus could not be achieved at VEp lower than 30 l/min particularly with low viscosity and low elasticity fluid. However, at high values of VEp, LLTS was comparable to that in the horizontal tube model with viscoelastic fluid, whereas LLTS of viscous liquid showed 26–40% lower than that in the horizontal tube model. The value of hs was 5–20% of the tube diameter at VEp of 30–60 l/min in both models. These results indicate that effective mucus clearance can be achieved by two-phase gas-liquid flow mechanism in patients with excessive bronchial secretions with biased tidal breathing favoring the expiratory flow and that the clearance can be further promoted by changing rheological properties of mucus.

Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

2012 ◽  
Vol 9 (1) ◽  
pp. 131-135
Author(s):  
M.A. Pakhomov
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Liquid Flow ◽  
Bubble Diameter ◽  
Gas Content ◽  
Two Phase ◽  
Eulerian Description ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow ◽  
The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

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