Kj. Elkow et Ks. Rezkallah, VOID FRACTION MEASUREMENTS IN GAS-LIQUID FLOWS UNDER 1-G AND MU-G CONDITIONS USING CAPACITANCE SENSORS, International journal of multiphase flow, 23(5), 1997, pp. 815-829
Capacitance void fraction sensors were used to obtain void fraction me
asurements in Vertical two-phase water-air flow in a small diameter tu
be (9.53 mm). Measurements were obtained at 1 - g and mu - g condition
s. Comparisons were made between the void fraction values obtained at
both gravity conditions by matching the flow rates obtained at mu - g
conditions. It was found that the average void fraction values were co
mparable for the bubble, transitional how (slug-annular flow at mu - g
, and churn flow at 1 - g), and annular flow regimes. The slug flow re
gime showed a slightly higher overall average of about 10% at mu - g c
onditions. The distribution coefficient, Ca, which takes into account
the flow regime and the void fraction profile was found to be 1.25 for
bubble and slug flows at mu - g, and 0.61 and 1.17 for 1 - g bubble a
nd slug flows, respectively. This suggests that a 'flatter' void fract
ion profile exists for slug flow at 1 - g as compared to mu - g. The v
alue of 0.61 for bubble flow agrees well with the typical values obtai
ned by averaging the 'saddle' shape void fraction profile typically se
en at 1 - g. (C) 1997 Elsevier Science Ltd.