Development of an Electrical Resistivity Probe for Void-Fraction Measurements in Air-Water Flow

Work was done on the adaptation of an electrical probe, developed by Neal for the measurement of local void fractions in mercury-nitrogen flow, to air- water flow. The adaptation is more difficult because of wetting of the probe by water. Various probe shapes and filming agents were employed without great success. Some improvement was obtained by means of a separate triggering circuit, but the calculated void fraction was still somewhat low compared with that measured by the gamma-ray-attentuation technique. Presumably, this is due to a finite response time of the probe, associated with the wetting of the tip; hence, further development of this technique is necessary. (auth