A. I. Chernov

An Investigation of the Mechanism of Acoustic Vibrations in Swirl Flows

An experimental setup is developed and systematic measurements are performed of pressure fields and amplitude-frequency characteristics of acoustic vibrations generated by impact swirl flows. A stable effect is revealed of generation of resonance acoustic vibrations under conditions of efflux of impact swirl jets. Curves are given of distribution of pressure on the obstacle surface for different values of the width of gap between the obstacle surface and the vortex chamber. The emergence of acoustic resonance with a frequency dependent on gas flow rate is registered for a certain correlation between the geometric parameters of the region of efflux of impact swirl air jet. An approximate analytical solution based on the use of a physical model of acoustic flow is obtained for theoretical description of the observed phenomenon of acoustic resonance in an impact swirl jet.

Experimental investigation of acoustic properties of titanium alloys in the temperature range of 20–1000°C

Titanium and titanium-based alloys, which are widely used in various sectors of the national economy, require deep and versatile investigations of their physico-mechanical properties in a wide temperature range. Numerous abnormal physical phenomena are observed in titanium-based alloys at high temperatures, especially in the region of polymorphic transformation. In particular, in addition to significant structural variations, which influence the strength properties of the final products, near such transformations the titanium alloys (especially with a fine structure) have a tendency to superplastic deformation, which is widely applied in modern technology. Among the physical characteristics, which provide extensive information about the structural and physico-mechanical properties of titanium alloys, are the temperature expansion and acoustic properties (in particular, the speed of ultrasound, information about the temperature dependence of which is unavailable for the majority of engineering materials), which allow the Young modulus for these materials to be calculated.

The Density of Liquid Sodium–Potassium Eutectic

The experimental investigations of the density of molten sodium–potassium alloys of eutectic composition, described in the literature, are briefly reviewed. This review is used to estimate the confidence error of the measurement results. The least squares method is used to simultaneously process the entire body of the experimental data on the density of the liquid Na–K eutectic. An approximating equation is derived for the temperature range from the melting point of the sodium–potassium eutectic to 1300 K. The mean-square error of the calculated values of the density of Na–K eutectic melt in the given temperature range is determined.

Investigation of the acoustic properties of zirconium

The results of an experimental study of the acoustic properties (speed and attenuation factor of ultrasound), the acoustic-emission properties, and the relative temperature expansion of zirconium in a temperature range of 20–1000°C are presented. The least-squares method was used to obtain approximating equations for the temperature dependences of the studied and calculated thermophysical properties of zirconium.

Investigation of the acoustic properties of cobalt

The results of the experimental investigation of the acoustic (ultrasound velocity and attenuation coefficient) and acoustic-emission properties, as well as of the relative thermal expansion of cobalt, within the temperature range of 20–1100°C are presented. By the mean square method, we obtain the approximating equations for the temperature dependencies of the investigated and the calculated thermophysical cobalt properties.

An investigation of the kinetics of structure transformations and phase transition in nickel using acoustic methods

Results are given of experimental investigation of the temperature dependence of the acoustic and acoustic-emission properties of nickel in the vicinity of magnetic phase transition (Curie point), as well as of their behavior in the process of annealing and quenching. The information content of these properties is demonstrated when investigating the evolution of nonequilibrium structures and phase transitions of metal materials.

Acoustic properties of titanium nickelide

Results of the experimental investigation of the acoustic properties of titanium nickelide alloy (speed of ultrasound and ultrasonic attenuation factor) are presented. The approximating equations for the temperature dependences of experimental data on the speed of sound, relative temperature expansion, and the density and Young’s modulus values calculated on their basis are obtained.