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This paper presents an experimental investigation of the dependence of the shape, structure, and opening angle of a water jet on the degree of superheating. The relationship between different boiling modes and characteristic shapes of a boiling jet has been revealed. It has been found that the shape and the opening angle of a superheated liquid jet under the same thermodynamic conditions change in different ways depending on the length of the jet. The changes in the opening angle of a boiling jet are presented in the meter, decimeter, and centimeter ranges.

The problem of the motion of a sphere in an ideal incompressible infinite fluid depths under ice cover with nonuniform compression was solved using the method of multipole expansions within the framework of the linear potential theory of waves. researched The hydrodynamic loads acting on the body such as the wave resistance and the lateral and lift forces were studied, and the deflection of the ice cover was analyzed as a function of its thickness, body speed, and the depth of submersion and direction of motion.

This paper presents the results of mathematical modeling of the propagation of air blast waves during methane explosion in mine workings taking into account their interaction with prefabricated parachute stoppings. Parachute stoppings are able to reduce the shock-wave intensity when the intensity of the incoming shock wave does not exceed the critical failure pressure of the stopping. The gas-dynamic method of calculating explosion-proof distances allows one to take into account parachute stoppings installed in various places of workings and to calculate the parameters of shock waves that have passed beyond the stopping.

The present paper describes the effects of hydrogen addition and carbon dioxide dilution in the natural gas on the velocity profiles and on the turbulent quantities (integral scale and Kolmogorov scale) in a cylindrical burner. The hydrogen content in the fuel is varied from 0 to 20 % in volume, and the volume of carbon dioxide is varied between 0 and 50 %. The velocity fields and the root mean square value of velocity are determined by the particle image velocimetry technique in the reacting flow. The concentrations of CO and NO _x are found using the corresponding analyzers. The turbulent quantities are determined by a numerical method. The results show that the absence of hydrogen and the carbon dioxide content greater than 20 % lead to flame blow-out. Therefore, the flame is hooked to the burner if hydrogen is added. In this study, with hydrogen addition, the difference in the maximum velocity ( U _max/ U ₀) along the bio-hythane jet is less important far from the burner due to the low density and high molecular diffusivity of hydrogen. The studies of the root mean square values of two velocity components ( U'_x and U'_z ) indicate that turbulence is more important for the U'_z component.

Even a slight change in the content of impurity gases during a self-propagating high-temperature synthesis can lead to a change in the combustion regime and the characteristics of the target products. In this work, the dependence of the burning rate of Ti + C granular mixtures on a titanium particle size is determined for the first time, and the effect of impurity gas evolution when using various allotropic modifications of carbon (graphite/soot) is studied. Experimental results are analyzed using the convective-conductive combustion model, which explains the strong influence of impurity gas release on the front velocity. Interaction rate of the components becomes a key factor for granular mixtures in which the influence of impurity gases is leveled. Experiments show that the burning rates of granular mixtures of titanium with soot are noticeably higher than the burning rates of a mixture of titanium with graphite. The curves approximating the dependence of the burning rate of a granular mixture of titanium and graphite on the size of titanium particles correspond to the linear law of interaction of the initial components. The interaction in a mixture of titanium and soot occurs according to the parabolic law.

This paper presents a combustion model for a solid fuel consisting of a matrix capable of self-sustained combustion and particles of a polydisperse coolant distributed in it. Heat transfer between the exothermically decomposing matrix and coolant particles in the condensed phase and the gas phase products of their gasification. The leading reaction in the region of the matrix and the evaporation surface of the coolant are assumed to be located on the interface. The heat consumption for the evaporation of the coolant is determined by the depth of its gasification during passage through the interface, which depends on the dispersion of the coolant and the burning rate of the fuel. Parametric identification of the model was carried out using data of sieve analysis of the granulometric composition of the coolant and an experimental dependence of the burning rate on pressure. It is shown that the model can be used to predict and providing the required ballistic characteristics of the fuel at the stages of its testing and series production.

Low-temperature (1 023 K) vacuum reduction of a mixture of zirconium dioxide with calcium is used to obtain a powder with an active zirconium content of 98.4 % (wt.). Physicochemical properties that determine the thermal and ignition characteristics of the powder and pyrotechnic compositions based on it are studied.

The explosive properties of cyclodextrin nitrates with various degrees of substitution of nitrate groups for hydroxyl groups in cyclodextrins. It is shown that charges of b-cyclodextrin nitrate with 100 % substitution at a density of 1.576 g/cm³ detonate with a relative explosion momentum equal to 96.4 % of its value for the 50/50 TNT/RDX composition with a density of 1.66 g/cm³, whose momentum is taken as 100 %. In this case, the detonation velocity is 7.15 km/s. It is concluded that the substance belongs to powerful blasting explosives. The sensitivity of cyclodextrin nitrates to mechanical influences was studied as a function of the degree of substitution. The obtained values of the explosive properties and sensitivity of cyclodextrin nitrates to impact and friction are compared with the properties of nitrocellulose.

The shock-wave initiation of an emulsion explosive was studied by flash radiography. Initiation was performed by impact of a thin Duralumin plate at a small angle to a flat surface of the explosive. The parameters of the initiating shock wave in the investigated explosive were estimated, and the depth of detonation initiation was measured.

Detonation overcompression during detonation convergence in a hemispherical charge of plasticized triaminobtrinitrobenzene with outer and inner radii of 75 and 20 mm after its initiation along the outer surface is studied. The experiment is numerically simulated with account for the transformation kinetics of an explosive into explosion products. The overcompressed detonation parameters in the explosive under study at a diagnosable charge radius of 20 mm are obtained via experiments and calculations: in the profile maximum, the pressure is 70 GPa, the front velocity is 9.45 km/s, and the mass velocity behind the front is 3.88 km/s. The overcompression achieved in the experiment under consideration is 2.3. The adiabatintersection point of the “nonreacting” explosive and its explosion products is revealed, which is implemented at a radius of 31 mm and a pressure of 52 GPa. The corresponding front velocity and the mass velocity behind the front at this point are 8.55 and 3.18 km/s. The resulting parameters at the adiabat intersection point are compared with the available literature data for triaminotrinitrobenzene and compositions based on it. A fairly large scatter of data is revealed. Suggestions are made about the causes of the scatter.