A characteristic of droplet-size measurements in two-phase flow

Raushenbakh (1964) has shown that the existence of a minimum radius of droplets that are stable in any high-velocity flow is based on the mutual action of the aerodynamic force and the sluggishness and deformability of the droplets. Lagunov (1972) has found that the maxima of the mass spectra (i.e., the fractional mass of droplets per unit volume of the gas), determined by the light scattering method in the throat of a Venturi tube shift toward smaller dimensions with increasing distance from the throat inlet. This contradicts Raushenbakh's stability criterion. In the present paper the reasons for this 'paradox' are identified from an analysis of the transformation of photographic spectra in the region of accelerated motion of two-phase flow. A method for measuring particle velocities, based on determining the scattering indicatrix at the test cross section and at the cross section of equalized phase velocities, is proposed.