A brief review of the relevant papers and an examination of the current status of research in the field of the acoustics of gas-particle suspensions are given. Non-stationary momentum, mass and energy transfer processes between a gas (vapour) and dispersed particles (droplets) under high-frequency acoustic perturbations are considered. A comparative evaluation of characteristic times and temperature differences for gas-particle and vapour-droplet mixtures subjected to acoustic perturbation is given. General dispersion equations to describe the propagation of weak monochromatic waves for a wide range of frequencies complying with the requirements of the acoustic homogeneity of the medium are derived. Frequency dependences of propagation velocity and attenuation coefficient of weak waves in water vapour-droplet mixtures are investigated. Frequency ranges are indicated over which different types of approximate theories are valid.

A. I. Ivandaev, A. G. Kutushev, and S. P. Rodionov UDC 532.529The first theoretical research on the wave dynamics of polydisperse gas suspensions was evidently carried out by Williams [1], who obtained intogrodifferential equations for the steady-state motion of a reactive collisionless mixture of a gaseous oxidizer and a sprayed liquid fuel with continuous distribution functions of drop size and velocity. Specific numerical calculations of the structure of a detonation wave in a gas-drop medium, however, were carried out in [1] using a distribution function that presumes a finite number of fractions of liquid particles. The laws of propagation of detonation waves in polydisperse sprays of fuel drops was subsequently studied within the framework of such a (multifractional) description of a collisionless disperse mixture (see, e.g., [2, 3]).A system of integrodifferential equations for the unsteady motion of a multifractional, inert, collisional gas suspension with a particle velocity distribution function was used in [4] to calculate the interaction of a shock wave with a bidisperse cloud of dusty gas. Very weak shocks in a cloud of a polydisperse, inert, collisionless gas suspension with a continuous particle size distribution function were studied theoretically in [5]. The equations of unsteady motion of a polydisperse gas suspension with a continuous particle size distribution function in a linear (acoustic) approximation were generalized in [6] to the case of phase transitions in vapor-drop media. The burning of mixtures of gaseous oxidizer with metallic inclusions in a chemical reactor was investigated in [7] within the framework of the equations of a polydisperse, reactive gas suspension with a continuous distribution function of current particle sizes.A model of the motion of a polydisperse, inert, collisionless gas suspension with a continuous particle size spectrum was developed in [8] and the adequacy of the proposed system of integrodifferential equations for describing actual shock processes in dusty gases was demonstrated, as confirmed by the satisfactory agreement between calculated and experimental data. In the present work we further develop the model of [8] for the case of a reactive, collisional gas suspension of unitary fuel with a continuous initial particle size distribution function.1. Main Assumptions and Equations. Suppose that we have a polydisperse gas suspension of unitary fuel with a continuous particle size spectrum. The usual assumptions in the mechanics of continuous disperse media [8, 9] are used to describe the motion of such a mixture: The characteristic sizes of the particles and the distances between them are considerably less than the characteristic scale of variation of the macroscopic parameters of the flow; the effects of viscosity and heat conduction are important only in the interaction between phases; the mixture is rarefied and the particles are spherical; the particles do not fragment or merge in their collisions with each other; collisions between polydisperse par...

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