Flow regime identification and void fraction measurement techniques in two-phase flow

Flow regime identification and void fraction measurement are considered in vertical two phase flow. A series of chordal void fraction measurements were made and formed into the probability density function and power spectral density function. The first four moments associated with these distributions were studied to obtain objective flow regime indicator. The PDF variance, or second moment about the mean, was found to be the best indicator of flow regime. A dual beam X-ray system was designed and constructed to make the chordal void fraction measurement required. This X-ray system employs a dc excited tube filament, full wave rectification and voltage filtering to produce a stable photon source. The large photon flux made analog linearization of the signal possible. Local void fraction measurements were made with a Karlsruhe impedance probe.