scholarly journals Overview of Void Fraction Measurement Techniques, Databases and Correlations for Two-Phase Flow in Small Diameter Channels

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 216
Author(s):  
Álvaro Roberto Gardenghi ◽  
Erivelto dos Santos Filho ◽  
Daniel Gregório Chagas ◽  
Guilherme Scagnolatto ◽  
Rodrigo Monteiro Oliveira ◽  
...  
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Measurement Techniques ◽  
Small Diameter ◽  
Phase Flow ◽  
Two Phase ◽  
Channel Diameter ◽  
Experimental Database ◽  
Absolute Relative Error ◽  
Fraction Measurement

Void fraction is one of the most important parameters for the modeling and characterization of two-phase flows. This manuscript presents an overview of void fraction measurement techniques, experimental databases and correlations, in the context of microchannel two-phase flow applications. Void fraction measurement techniques were reviewed and the most suitable techniques for microscale measurements were identified along its main characteristics. An updated void fraction experimental database for small channel diameter was obtained including micro and macrochannel two-phase flow data points. These data have channel diameter ranging from 0.5 to 13.84 mm, horizontal and vertical directions, and fluids such as air-water, R410a, R404a, R134a, R290, R12 and R22 for both diabatic and adiabatic conditions. New published void fraction correlations as well high cited ones were evaluated and compared to this small-diameter void fraction database in order to quantify the prediction error of them. Moreover, a new drift flux correlation for microchannels was also developed, showing that further improvement of available correlations is still possible. The new correlation was able to predict the microchannel database with mean absolute relative error of 9.8%, for 6% of relative improvement compared to the second-best ranked correlation for small diameter channels.

Application of Neutron Radiography to Visualization and Void Fraction Measurement of Air-Water Two-Phase Flow in a Small Diameter Tube

1993 ◽  
Vol 30 (6) ◽  
pp. 516-523 ◽  
Author(s):  
Takashi HIBIKI ◽  
Kaicbirol MISHIMA ◽  
Kenji YONEDA ◽  
Shigenori FUJINE ◽  
Keiji KANDA ◽  
...  
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Neutron Radiography ◽  
Small Diameter ◽  
Phase Flow ◽  
Two Phase ◽  
Fraction Measurement

Void fraction measurement of the air-water two-phase flow in the sub-channel of a rod bundle geometry based on an impedance meter

2018 ◽  
Vol 115 ◽  
pp. 480-486 ◽  
Author(s):  
Bin Yu ◽  
Wenxiong Zhou ◽  
Liangming Pan ◽  
Hang Liu ◽  
Quanyao Ren ◽  
...  
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Rod Bundle ◽  
Fraction Measurement ◽  
Impedance Meter

Void fraction measurement in modeled two-phase flow inside a vertical pipe by using polyethylene phantoms

2015 ◽  
Vol 40 (44) ◽  
pp. 15206-15212 ◽  
Author(s):  
Reza Faghihi ◽  
Mohammadreza Nematollahi ◽  
Ali Erfaninia ◽  
Mahtab Adineh
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Vertical Pipe ◽  
Two Phase ◽  
Fraction Measurement

Void Fraction Measurements for Air-Water Pipe Flows Using Quick-Closing Valves and Wire-Mesh Sensors

2018 ◽  
Author(s):  
Étienne Lessard ◽  
Jun Yang
Keyword(s):  
Void Fraction ◽  
Test Section ◽  
Two Phase Flow ◽  
Measurement Techniques ◽  
Wire Mesh ◽  
Axial Distance ◽  
Phase Flow ◽  
Flow Conditions ◽  
Flow Loop ◽  
Two Phase

In support of a header/feeder phenomena study, an adiabatic, near-atmospheric, air-water flow loop was commissioned simulating a single feeder of a Pressurized Heavy Water Reactor’s primary heat transport system under a postulated Loss of Coolant Accident scenario. An extensive database in representative two-phase flow conditions was collected, 750 tests in total, in order to create a two-phase flow map to be used in the more complex geometries such as header/feeder systems. The flow loop consists of two vertical test sections, for upwards and downwards flow, and one horizontal test section, each with an inner diameter of 32 mm and at least 120 diameters in length. Superficial velocities extended up to 6 m/s for the water and 10 m/s for the air. Void fraction was measured by means of quick-closing valves and a pair of wire-mesh sensors (WMS) in each test section. Two-phase repeatability tests showed that the liquid and gas superficial velocities varied by 1.1% and 0.6% at reference conditions of 2.0 and 2.8 m/s, respectively. The corresponding void fraction measurements varied for the quick-closing valves by at most 6.8%, which indicates a low sensitivity to the closure time of the valves and an appropriate axial distance between them, and 2.3% for the WMS. For both measurement techniques, the largest variations occurred in the vertical downwards test section. For the formal two-phase tests, over 600 distinct flow conditions were performed. The results showed that the two measurement techniques agreed within 5% at high void fractions and low liquid flow rates in vertical flow. For all other cases corresponding to the transitional or dispersed bubbly flow regime, the WMS over-estimated the void fraction by a consistent bias. An empirical correction is proposed, with a root-mean-square error of 6.6% across all tests. The void fraction map resulting from this database provides validation for the WMS measurements, a quantitative assessment of its uncertainty and range of applicability, and will be used as a reference in future tests under similar scale and flow conditions.

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