The prediction of vapor/gas volume fraction in a liquid media in a rapidly depressuring system is a problem which arises in numerous technical applications. The solution requires knowledge of the number of bubbles per unit volume of the flashing mixture, as well as the volumes of the individual bubbles, as a function of time. Carefully-controlled depressurization experiments are performed in a vertical shock tube, in which mean void fraction will be measured as a function of time and pressure, with and without the presence of stainless-steel surfaces using deaerated distilled water. The nucleus distribution function is determined from these data by a numerical inversion of the integral equation, or approximately by an inverse transform procedure. This experimental work gives information on the effective distribution of bubble nucleii on typical engineering surfaces.
