Influence of Flow Angularities in a Hypersonic Ramjet Diffuser on the Formation of the Shock‐Wave Structure of the Real Gas Flow

We have investigated the shockwave structures arising at the entrance to the engine section of hypersonic aircraft and the influence on the process of their formation of the flow angularity after oblique shock fronts incident inside the diffuser with a different type of interaction (Mach or regular). To take into account the real properties of the atmosphere, we used the effective adiabatic exponent method permitting determination of the topology of shockwave patterns and calculation of the gas and thermodynamic parameters in various flow zones between the shock fronts in a wide range of diagnostic variables for the Earth's atmosphere.     

Equalization of the Concentration of a Scalar Impurity in a Flow‐Type Chamber

Experimental and theoretical investigations of the time of equalization of the concentration of an impurity in a rectangular flowtype chamber have been carried out. It has been shown that the process of equalization of the concentration with time is exponential in character. The characteristic equalization time has been computed using the theory of turbulent diffusion. Theoretical results describe experimental regularities with an accuracy of about 10%. The value of the coefficient of turbulent diffusion for different configurations of flows in the chamber has been obtained from a comparison of experimental and calculated results.     

Heat‐Transfer Processes in a Plasma Reactor in Destruction of Pesticides

The possibility of using a multijet electric arc plasmachemical reactor for decontamination and destruction of different powder pesticides with an expired effective date and storage life which have not been used in agriculture is studied. Studies of heat transfer are conducted on a setup operating without processing of raw material and with supply of pesticides (isophen and butyl ester of 2,4dichlorophenoxyacetic acid) to the reactor. The composition of waste gases at the reactor outlet is studied.     

Stationary Waves in a Supersonic Flow of a Two-Component Bose Gas

A stationary wave pattern occurring in a flow of a two-component Bose-Einstein condensate past an obstacle is studied. We consider the general case of unequal velocities of two superfluid components. The Landau criterium applied to the two-component system determines a certain region in the velocity space in which superfluidity may take place. Stationary waves arise out of this region, but under the additional condition that the relative velocity of the components does not exceed some critical value. Under increase of the relative velocity the spectrum of the excitations becomes complex valued and the stationary wave pattern is broken. In case of equal velocities two sets of stationary waves that correspond to the lower and the upper Bogolyubov mode can arise. If one component flows and the other is at rest only one set of waves may emerge. Two or even three interfere sets of waves may arise if the velocities approximately of equal value and the angle between the velocities is close to π/2. In two latter cases the stationary waves correspond to the lower mode and the densities of the components oscillate out-of-phase. The ratio of amplitudes of the components in the stationary waves is computed. This quantity depends on the relative velocity, is different for different sets of waves, and varies along the crests of the waves. For the cases where two or three waves interfere the density images are obtained.     

Homogeneity of the Electric‐Discharge Plasma in a Coaxial Flash Lamp

The main factor that sharply decreases the efficiency of the employment of a pulsed‐discharge xenon plasma as an emitter in electric‐discharge sources of pumping of dye lasers is a macroscopic loss of stability of the discharge in the temperature and pressure ranges selected. It has been established that in the pressure range of 1–?10 torr, an increase in the temperature of a pulsed‐discharge xenon plasma results in the mechanism of conduction becoming purely collisional. Stabilization of macroinstabilities in the plasma has been attained using a sectioned return current conductor in a flash coaxial lamp. It has been verified by experiment that uniformity of the sectioning ensures a high degree of homogeneity of the electric‐discharge plasma in the discharge space.     

Numerical Analysis of the Jet‐Vortex Pattern of Flow in a Rectangular Trench

Numerical simulation of the vortex structure of threedimensional laminar flow in a rectangular trench of square cross section has been carried out on the basis of the finitevolume solution of steadystate Navier–Stokes equations.     

Conduction and Radiation of a Xenon Plasma in Electric‐Discharge Pumping Sources

A quantitative analysis of the conditions of stabilization of the conduction of a plasma at the leading edge of an electricdischarge pulse in xenon is performed. The ranges of gas pressures and plasma temperatures in the region of stabilization are estimated. It is established that the homogeneity of the discharge plasma is the deciding factor for stabilization of its conduction. It is noted that under certain conditions selfstructurization of the plasma is attained. The role of impurities in the formation of the mechanism of conduction and their influence on the plasma radiation are evaluated. Calculated data are compared with data of experiments.     

Cooling of a coarse lump in a bed of “fine” particles

The cooling of a coarse lump having the form of a rectangular prism in a blow-through bed of fine particles is discussed. A solution is obtained for large and small values of Fo by using Laplace transforms.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 30, No. 3, pp. 434–440, March, 1976.     

Investigation of the Processes in Torches for High‐Speed Gas‐Plasma Spraying of Powder Materials with the Use of the Flow‐Rate Method of Action on the Flow

The comparative characteristic of torches with geometric and flowrate methods of control of the characteristics of a twophase flow are given. Based on the mathematical model proposed, the advantage of the flowrate method is shown by calculation. By using particular examples, the estimates of the optimum values are given for the relation of the flow rates in feeding units and for the length of the heating portion for torches with a flowrate method of control of the twophase flow.     

Identification of Heat‐Exchange Processes in a Supersonic Spatial Flow Past Aircraft

Direct and inverse problems of heat exchange in a supersonic spatial flow past the front part of an aircraft in the form of a spherically blunted nose cone have been solved numerically. The prospects of using highheatconductivity materials and the blowing of the gascoolant for lowering the temperature on the surface of an aerodynamic body have been shown. A comparison of the solutions of the direct and inverse problems in one, two, and threedimensional formulations for various materials of the sheath has been made. The error in recovering the heat flow by the thinwalled method has been estimated.     

Synthesis of Carbon Fibers in the Decomposition of Acetylene and Propane–Butane Mixture in a Plasma Jet

Carbon fibers are prepared during the conversion of acetylene and propane–butane mixture in a jet of the helium and argon plasma without using catalysts. The synthesis is carried out in a plasma jet reactor. The synthesis products are studied by electron microscopy, synchronous thermal analysis and energy dispersive X-ray spectroscopy. The effect of the synthesis parameters on the structure and properties of the carbon fibers prepared in the volume is established. When the propane–butane mixture is decomposed in an inert medium, conditions are found for the synthesis of cylindrical carbon nanofibers of a tortuous shape with a diameter of up to 20 nm and a length-to-diameter ratio of up to 1000. The decomposition of acetylene at 350 Torr produces nanofibers formed by a chain of straight cylinders with a diameter of up to 20 nm, and cylindrical fibers are synthesized in the form of spirals of up to 200 nm in diameter at 150 Torr.     

Dynamics of Plasma in a Plasma-Microwave Amplifier under the Action of the Miller’s Force

High Temperature - In this paper, we consider the dynamics of plasma in a high-power plasma-microwave amplifier with a submicrosecond pulse duration. It is shown that, in the case of a linear mode...