V. V. Volodin

Inhibition of Spontaneous Decomposition of Acetylene by Hydrocarbon and Hydrogen

An experimental study is made of the process of inhibition of exothermal spontaneous decomposition of acetylene by diluting it with a household gas (propane/butane) and hydrogen, which serve as fuel themselves. A mixture of acetylene with inhibitor, located in a cylindrical shock tube, is heated by a reflected shock wave. The shock waves are provided by detonation waves that are initiated in a stoichiometric acetylene-oxygen mixture. The detonation waves change to shock waves in the acetylene-inhibitor mixture. Minimal limits of bulk concentration of inhibitors are obtained, at which no spontaneous decomposition of acetylene occurs.

Influence of an Acoustic Field on Flame Development and Transition to Detonation

The work is devoted to experimental and numerical study of flame interaction with acoustic waves in closed and semiclosed pipes filled with preliminarily mixed gaseous mixtures. We analyze the influence of eigenfield (generated by the flame itself) and external acoustic field on the flame dynamics. We show that acoustic field affects the combustion process at all stages. The effect increases with any increase in the energy of initiation of combustion. At later stages of flame development, acoustic waves can initiate the transition to detonation or prevent it. Thus, it is possible to control the combustion modes using external acoustic field.

An experimental study of the diffusion-controlled self-ignition of hydrogen in a channel

The pulsed outflow of hydrogen into channels of circular and rectangular cross sections with a surface area of 20 mm2 was experimentally studied. It was revealed that the shock wave formed during the outflow of a pulsed jet is the reason why it ignites at the contact surface. The range of initial pressures of hydrogen at which it ignites was determined and the dependence of the distance from the diaphragm at which a flame arises at the contact surface on the pressure in the shock wave front for circular and rectangular cross section channels was obtained.

Optimizing the efficiency of dielectric barrier discharge for creating synthetic jets

A study of synthetic jets created by dielectric barrier discharge of the symmetric actuator has been carried out. The parameter—specific thrust (thrust-to-power ratio)—is used for the first time. The current–voltage characteristics of the dielectric barrier discharge are obtained at different values of the ballast resistance. The dependence of the thrust-to-power ratio on the supply-voltage frequency is determined experimentally.

The effect of reflected acoustic disturbances on flame front acceleration

The frequency spectrum of acoustic disturbances that are emitted by accelerating flame front in an air–hydrogen mixture within an axially symmetric channel with a uniform cross section is experimentally determined. The effect of acoustic disturbances that are reflected from the closed end of the combustion chamber on the flame front acceleration is studied. It is revealed that the frequency spectrum of generated acoustic vibrations under experiment conditions has maximums at frequencies close to 250, 800, and 1500 Hz. The average flame velocity is 200 m/s. Spectra of generated acoustic vibrations and the flame front velocity depending on the material of the closed end of the axially symmetric channel are obtained for the stoichiometric air–hydrogen mixture.

Experimental Study of the Development of a Helium Jet during Acoustic Action

A helium jet subjected to acoustic action is experimentally studied by the particle image velocimetry method. The mechanisms of flow stability loss are discussed. An asymmetric instability mode is shown to develop in the jet subjected to the action of sound, which leads to jet division. Jet vibrations are found to be accompanied by a secondary instability, which manifests itself in the formation of vortices inside the jet.

Blast wave reflection from lightly destructible wall

The paper presents the results of experimental study of the action of blast waves on the obstacle made of different materials. The pressure in the front of reflected blast wave is compared in the cases of its interaction with a rigid metal wall and the destructible wall made of weakly cemented sand.

Inhibition of explosive decomposition of acetylene

An experimental study of the inhibition of the exothermic decomposition of acetylene diluted with household propane+butane mixture and hydrogen was performed. Acetylene-inhibitor mixtures were heated behind reflected shock waves. The shock wave was generated by the detonation wave initiated in a stoichiometric acetylene-oxygen mixture. The minimum volumetric inhibitor concentrations capable of suppressing the self-decomposition of acetylene were determined.