Analysis of nonsteady flows with phase conversions

An investigation is made of nonsteady flows of a compressible medium with nonuniform phase conversions. It is noted that such media exhibit expansion processes with large supercooling values and a subsequent spontaneous condensation in which a large amount of heat is released. Under conditions such that condensation occurs at Mach numbers approaching unity, nonsteady flow regimes may be generated. A study is made of the frequency characteristics of nonsteady flow regimes associated with spontaneous moisture formation in Laval nozzles. In order to determine the dependence of the dimensionless frequency of the nonsteady process on the Mach number in the zone of spontaneous condensation, a similarity theory is employed. The dependence is applicable to defining the design frequency of the nonsteady process in condensation flow by consideration of the stagnation parameters at nozzle entry and the known duct geometry.