V. A. Arkhipov

Laboratory Method for Measurement of the Specific Impulse of Solid Propellants

A new laboratory express-method of determining the specific impulse of solid propellants based on the measurement of the reactive force of gasification products escaping from the burning propellant surface is presented in this work. The values of the specific impulse for a model composite solid propellant by varying the pressure in the combustion chamber are determined.

Hydrodynamics and Heat Transfer in the Coolant Flows in the Elements of the Technical Designs of Industrial Systems

Numerical simulation of the motion of a viscous incompressible nonisothermal liquid in an open rectangular cavity with a glance of heterogeneity phase characteristics is performed. The hydrodynamic pattern of moving liquid has been obtained. Temperature profiles for solid and liquid phases have been received. The model parameters influence on the motion of the heat carrier and the distribution of temperatures in two phases have been studied.

Nanometals: Synthesis and Application in Energetic Systems

Abstract A survey of metal nanopowders or nanometals (mostly produced by electrical explosion of wires) usage in different energetic systems is carried out with the focus on nanometals combustion efficiency. Improved kinetic characteristics of chemically reacting systems (ignition, burning rate enhancement for propellants, explosives, and thermites) are typical for nanoaluminum, nAl. A weak correlation between nAl properties and the slow oxidation parameters was found as the result of a very wide scatter in powder characteristics. The burning rate enhancement was analyzed for nAl-loaded solid propellants. The most promising energetic systems are nAl-loaded solid fuels (HTPB-based, ice-based, etc.) with chemically inert matrices.

Unsteady rise of a bubble in a viscous fluid at small Reynolds numbers

A bubble rising from the state of rest in a viscous incompressible fluid is considered. A formula for the Basset force acting on the bubble in a viscous fluid is obtained, which differs by a multiplier from the Basset force for a solid particle. The problem of unsteady rise of a bubble is solved analytically. The bubble rise is also studied experimentally and the experimental data are compared with the theoretical results.

Solid propellant combustion in a high-velocity cross-flow of gases (review)

Combustion of solid propellants in rocket propulsion systems usually occurs in an intense cross-flow of combustion products (solid rocket motor), gaseous oxidizer (hybrid rocket motor) or air (ramjet and air-breathing engines). This leads to the so-called erosive burning effects, resulting in a change in the burning law under the influence of the gas flow. The main approaches to modeling the erosive burning of solid propellants in a high-velocity cross-flow of gases are considered. Methods for the criterial description of the results of experimental studies of the erosive burning of solid propellants under transonic and supersonic flow conditions are analyzed.

Equilibrium shapes and stability of rotating drops

Direct variational methods are used to obtain nonaxisymmetric equilibrium shapes of a rotating drop. The results are given of experiments on the interaction of freely floating drops of viscous fluid. It is shown that if the dimensionless angular momentum of the system is Ω > 3.4, then a sequence of three-dimensional shapes similar to ellipsoids bifurcates from the sequence of axisymmetric shapes The stability of these shapes is studied in Poincarés scheme.

Optimization of construction of a shell for launcher in the water medium in the supercavitation regime

New scheme of a shell, providing increase in range and stability of the movement in the water medium due to realization of the supercavitation regime on all trajectory of its movement, has been considered. The results of the analysis in the efficiency of the movement of a shell in the water environment in the supercavitation mode are presented.

Numerical Simulation of Heat Transfer in a Closed Two-Phase Thermosiphon

This paper presents the results of mathematical modelling of three–dimensional heat transfer in a closed two-phase thermosyphon taking into account phase transitions. Three-dimensional conduction equation was solved by means of the finite difference method (FDM). Locally one-dimensional scheme of Samarskiy was used to approximate the differential equations. The effect of the thermosyphon height and temperature of its bottom lid on the temperature difference in the vapor section was shown.

Regimes of sedimentation of a consolidated system of solid spherical particles

The results of the experimental investigation of gravitational sedimentation of a consolidated system of solid monodisperse spherical particles in a viscous liquid are represented over wide ranges of the particle number density and the Reynolds and Stokes numbers. Empirical dependences of the velocity of sedimentation of a particle aggregate and the drag coefficient of a system of particles as functions of the initial volume number density are obtained. The boundary values of the particle number density separating the sedimentation regimes are determined.

Performance optimization of a standard-flow hybrid rocket engine

A method for performance optimization of a standard-flow hybrid rocket engine is considered. The method is based on inserting an additional amount of an oxidizer into a solid propellant with a prescribed distribution of the oxidizer mass fraction along the solid propellant charge. An analytical dependence is derived for the oxidizer fraction distribution that ensures uniform combustion and high efficiency of the solid propellant charge.