Void Fraction Fluctuations in Two-Phase Flow at 1-G and μ-G

Void fraction measurements for adiabatic, two-phase vertical upward, water-air flow in a 9.53 mm ID tube were obtained using a helical wound capacitance sensor. Comparisons were made between 1-g and μ-g void fraction values by matching the flow rates obtained at μ-g conditions. A Probability Density Function was used to analyze the void fraction signals. It was found that a wider fluctuation in void fraction values occurred for slug flow at 1-g as compared to μ-g. For higher flow rates such as with annular flow, inertia forces become dominant. For these flows it was found that the void fraction fluctuations were similar at 1-g and μ-g conditions.