scholarly journals Experiment investigation of two-phase flow pattern transition and frictional pressure drop of R600a in a horizontal tube

2017 ◽  
Vol 63 (1) ◽  
pp. 98-107 ◽  
Author(s):  
Zhiqiang Yang ◽  
Maoqiong Gong ◽  
Gaofei Chen ◽  
Xin Zou ◽  
Xiaoru Zhuang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Horizontal Tube ◽  
Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Flow Pattern Transition

Experimental Investigation on Flow Patterns and Frictional Pressure Drop of Downward Air-Water Two-Phase Flow in Vertical Pipes

2013 ◽  
Author(s):  
Yuqing Xue ◽  
Huixiong Li ◽  
Tianyou Sheng ◽  
Changjiang Liao
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Oil Recovery ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Vertical Pipe ◽  
Two Phase Flows ◽  
Two Phase ◽  
Frictional Pressure Drop

A large amount of air need be transported into the reservoir in the deep stratum to supply oxygen to some microbes in Microbial Enhanced Oil Recovery (MEOR). Air-water two-phase flows downward along vertical pipeline during the air transportation. Base on the experiment data described in this paper, the characteristics of air-water two phase flow patterns were investigated. The flow pattern map of air-water two phase flows in the pipe with inner diameter of 65 mm was drawn, criterions of flow pattern transition were discussed, and the dynamic signals of the pressure and the differential pressure of the two phase flow were recorded to characterize the three basic flow regimes indirectly. The frictional pressure drop of downward flow in vertical pipe must not be disregarded contrast with upward two phase flow in the vertical pipe because the buoyancy must be overcame when the gas flows downward along pipe, and there would be a maximum value of frictional when the flow pattern translated from slug flow to churn flow.

Flow Characteristics and Frictional Pressure Drops of Gas-Liquid Two-Phase Flow in Mini-Micro Pipes and at Vena Contract and Expansion

2007 ◽  
Author(s):  
Hiroyasu Ohtake ◽  
Hideyasu Ohtaki ◽  
Yasuo Koizumi
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Liquid Velocity ◽  
Flow Patterns ◽  
Experimental Results ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Frictional Pressure Drop

The frictional pressure drops and two-phase flow patterns of gas-liquid two-phase flow in mini-micro pipes and at vena contract and expansion were investigated experimentally. Test liquid was water; test gas was argon. The diameter of the test mini-pipe was 0.5, 0.25 and 0.12 mm, respectively. The pressure drop data and the flow pattern were collected over 2.1 < Ug < 92.5 m/s for the superficial gas velocity and 0.03 < Ul < 10 m/s for the superficial liquid velocity. The experimental results show that the flow patterns were slug, churn, ring and annular flows; pure bubbly flow pattern was not observed in a range of the present experimental conditions. The two-phase friction multiplier data for D > 0.5 mm showed to be in good agreement with the conventional correlations. On the other hand, the two-phase friction multiplier data for D < 0.25 mm differed from the calculated values by the conventional correlations. Then, thickness of liquid film around a gas plug and size of gas core were estimated and the effect of frictional pressure drop on channel size was discussed through Knudsen Number of gas and instability on liquid-gas interface. The coefficients of sudden enlargement and sudden contraction in mini-pipes for the gas-water two-phase flow were modified from the present experimental results.

Two-Phase Flow Through Square and Circular Microchannels: Effect of Channel Geometry

2003 ◽  
Author(s):  
Peter M.-Y. Chung ◽  
Masahiro Kawaji ◽  
Akimaro Kawahara ◽  
Yuichi Shibata
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Square Channel ◽  
Circular Microchannel ◽  
Square Microchannel

An adiabatic experiment was conducted to investigate the effect of channel geometry on gas-liquid two-phase flow characteristics in microchannels. A mixture of water and nitrogen gas was pumped through a 96 μm × 96 μm square microchannel and the flow pattern, void fraction and pressure drop data were obtained and compared with those previously obtained in a 100 μm circular microchannel. The frictional pressure drop was determined from the measured total pressure drop, and the two-phase flow pattern and void fraction were determined from image analysis of the video recordings. In the square channel, 136 runs were performed over a range of 0.09 ≤ jG,AVG ≤ 62 m/s for the average superficial gas velocity and 0.01 ≤ jL ≤ 4 m/s for the superficial liquid velocity. The frictional pressure drop data showed that the calculations based on a separated–flow model were best at estimating the frictional pressure drop for both microchannels. No particular effect of the channel shape was found for the two-phase frictional pressure drop. The void fraction-to-volumetric quality relationship was also found to be similar for both shapes of microchannels, exhibiting an exponential increase in void fraction with increasing volumetric quality. The empirical correlation that describes the void fraction-to-volumetric quality relationship for the square microchannel was developed earlier from the measured data for the circular microchannel. Observations of the recorded images indicated the two-phase flow patterns to be primarily intermittent with liquid and gas slugs. The liquid film surrounding the gas core displayed a smooth or ring-like structure. The probability of each interfacial structure occurring was examined in detail to develop a novel flow pattern map consisting of four regions named slug-ring flow, ring-slug flow, multiple flow and semiannular flow. Between the square and circular microchannels, the two-phase flow maps exhibited transition boundaries that were shifted depending on the channel shape. The region of ring-slug flow that appears in the circular microchannel collapsed in the square microchannel, possibly due to the suppression of the liquid-ring film in the corners of the square channel.

Determination and Characteristics of the Transition to Two-Phase Slug Flow in Small Horizontal Channels

1994 ◽  
Vol 116 (1) ◽  
pp. 140-146 ◽  
Author(s):  
M. W. Wambsganss ◽  
J. A. Jendrzejczyk ◽  
D. M. France
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Slug Flow ◽  
Static Pressure ◽  
Two Phase Flow ◽  
High Mass ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Pattern Transition ◽  
Phase Pressure

Two-phase pressure drop and fluctuating static pressures were measured in a small horizontal rectangular channel (hydraulic diameter = 5.44 mm). The two-phase fluid was an air/water mixture at atmospheric pressure tested over a mass flux range of 50 to 2000 kg/m2˙s. Two-phase flow patterns were identified and an objective method was found for determining the flow pattern transition from bubble or plug flow to slug flow. The method is based on an RMS static pressure measurement. In particular, it is shown that the transition is accompanied by a clear and abrupt increase in the RMS pressure when plotted as a function of mass quality. Use of the RMS pressure as a two-phase flow pattern transition indicator is shown to have advantages over pressure-versus-time trace evaluations reported in the literature. The transition is substantiated by a clear local change in slope in the curve of two-phase pressure drop plotted as a function of either Martinelli parameter or mass quality. For high mass fluxes, the change in slope is distinguished by a local peak. Some degree of substantiation was found in previous work for both of the results (the RMS static pressure change and the local pressure drop change) at the transition to slug flow.

Two-Phase Flow and Heat Transfer in Rectangular Micro-Channels

2003 ◽  
Author(s):  
Weilin Qu ◽  
Seok-Mann Yoon ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Heat Sinks ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase ◽  
Micro Channels

Knowledge of flow pattern and flow pattern transitions is essential to the development of reliable predictive tools for pressure drop and heat transfer in two-phase micro-channel heat sinks. In the present study, experiments were conducted with adiabatic nitrogen-water two-phase flow in a rectangular micro-channel having a 0.406 × 2.032 mm cross-section. Superficial velocities of nitrogen and water ranged from 0.08 to 81.92 m/s and 0.04 to 10.24 m/s, respectively. Flow patterns were first identified using high-speed video imaging, and still photos were then taken for representative patterns. Results reveal that the dominant flow patterns are slug and annular, with bubbly flow occurring only occasionally; stratified and churn flow were never observed. A flow pattern map was constructed and compared with previous maps and predictions of flow pattern transition models. Annual flow is identified as the dominant flow pattern for conditions relevant to two-phase micro-channel heat sinks, and forms the basis for development of a theoretical model for both pressure drop and heat transfer in micro-channels. Features unique to two-phase micro-channel flow, such as laminar liquid and gas flows, smooth liquid-gas interface, and strong entrainment and deposition effects are incorporated into the model. The model shows good agreement with experimental data for water-cooled heat sinks.

Sign in / Sign up

Export Citation Format

Share Document