The effect of multicomponent diffusion on supersonic flow of carbon dioxide past bodies

Different approaches are considered to the inclusion of multicomponent diffusion into numerical analysis of supersonic flow of carbon dioxide past blunt-nosed bodies. Calculation results are given, which illustrate the effect of diffusion processes on heat transfer to the surface of a space vehicle moving in the atmosphere of Mars.     

Velocity profile in a turbulent boundary layer of a supersonic gas stream

A semiempirical equation is proposed for relating the coefficients of molecular and turbulent viscosity in the laminar sublayer and in the transition region. Simple formulas are derived for determining the velocity throughout the boundary layer and the frictional stress at the surface of a plate at various values of the Mach number. The results of calculations are compared with experimental data.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 23, No. 1, pp. 112–120, July, 1972.     

Effect of swirl flow on an atmospheric inductively coupled plasma supersonic jet

Recently supersonic jets extracted from atmospheric inductively coupled plasmas (ICP) have attracted a lot of attention. Usually atmospheric ICP generators have employed swirl flow injection in order to stabilize the plasma. However the effect of the swirl flow injection on the performance of atmospheric ICP generators has not been understood enough. This work found that the injection of the swirl flow deteriorates the performance. First we conducted the total enthalpy measurement based on the sonic flow method and evaluated the averaged specific enthalpy. Then laser absorption spectroscopy was employed in order to measure the temperature and the velocity of the extracted supersonic jet. The both measurements observed that the specific enthalpy of the jets decreased with the increase in the swirl flow fraction. This would be because the swirl flow affected the shape and the position of the plasma significantly.     

Numerical simulation of the flow around a blunt body in supersonic polydisperse stream

The work is devoted to numerical simulation of the flow around blunt bodies in supersonic streams containing solid polydisperse particles. We consider a widespread variant of two-parameter gamma function for the particle size distribution. To account for interparticle collisions and interactions of particles with a streamlined surface, the direct numerical simulation of collisional dynamics for the dispersed phase was used. The local particle size distribution near the streamlined surface is studied. The screening effect due to the interaction of the incident and reflected from the surface particles is analyzed. It is noted that the energy flux from a polydisperse admixture to the streamlined surface can be represented with sufficient accuracy by equivalent impact of monodisperse admixture.     

Simulation of the supersonic turbulent flow around a cylinder with coaxial disks

The turbulent axisymmetric flow around a stepped body — a cylinder with coaxial front and rear disks — has been calculated with the aid of a VP2/3 package based on multiblock computational technologies and the generalized procedure of pressure correction. The computational model has been tested with the example of a supersonic flow around a sphere. The numerical forecasts made with the use of Spalart–Allmares shear stress transfer and eddy viscosity transfer models have been compared with the data of the aeroballistic experiment, wind tunnel tests, and the results of the calculation of the flow around the disk–cylinder arrangement by a simplified zonal model in a wide range of variation of the incident flow Mach number (from 1.5 to 4). We have obtained a good agreement between the calculated transverse flow density distributions in the front stalling zone and those determined from the interferograms for the wave-drag-rational disk–cylinder arrangement. The influence of the rear disk on the drag of the disk–cylinder–disk arrangement has been estimated.     

The effect of diffusion processes on the interaction in multicomponent silicate systems

The results of studying diffusion processes in silicate multicomponent systems, which are widely used as binders in variously purposed composite materials, have been generalized and described. It has been shown that the effective diffusion coefficients of alkali and alkaline-earth cations in a diffusion pair are not a single-valued function of the ion radius of the cation but depend on structural factors and on the energy of the cation bonding with other ions of the melt.     

The effect of particles on the gas velocity in a free turbulent flow

The article describes experimental studies carrid out to investigate the interaction between gas and particles in a free turbulent two-phase flow at the outlet from a rather long vertical tube.Notation A cross-sectional area of the flow - A ₀ initial cross-sectional area of the flow - d diameter of the flow - d _p average diameter of particles - I _i initial momentum of the two-phase flow - k mass ratio of particles and gas (k=m _p/m _g) - k ₀ mass ratio of particles and gas in the initial cross-section of the two-phase flow (x=0) - m _g mass flow rate of gas - m _p mass flow rate of particles - r instantaneous radius of the flow - r ₀ radius of the initial cross-section of the flow - r _1/2 normal distance from the flow axis to the point at which the velocity of gas is equal to the half of the axial velocity - R cross-sectional radius of the flow - u velocity - u _a air velocity - u _fa gas velocity on the flow axis - u _g gas velocity - u _av average gas velocity in the initial cross-section for two-phase and single-phase flows - u ₀ gas velocity on the axis of the initial cross-section of the flow - u _p particle velocity - x distance along the axis from the original of coordinates - _g gas density Institute of Nuclear Research Vina, Laboratory of Thermal and Power Engineering, Belgrade, Yugoslavia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 3, pp. 361–365, May–June, 1995.     

Peculiarities of flow over a blunted body by a supersonic polydispersed jet with a swirl of reflected particles

The acceleration of monodispersed and polydispersed axisymmetric nozzle flows and their interaction with a sphere are investigated. The formulas given in [1] are applied to the recovery coefficients of velocity components of reflected particles. For the development of a physicomathematical model, semiempirical information on the influence of particle rotation on coefficients of its interaction with a carrier continuous medium, the Magnus force, and the damping torque are taken into account. Numerical investigations are carried out for a characteristic mass spectrum of particles as a set of several fractions [2]. It is demonstrated that the rotation of monodispersed particles leads to the caustic (envelope of paths of reflected particles) moving away from the body in the flow. The algorithm elaborated enables specific details of the mass spectrum of the particles bombarding the body with known thermomechanical properties and coefficients of their interaction with the body surface to be estimated by comparing experimental and numerical results.     

The effect of liquid flow swirl on the intensification of convection heat transfer in a circular cylindrical tube

We present the results from an analytical study of the distribution of velocities and heattransfer characteristics for a single case of vortex flow in a compressible ideal liquid, under the condition that the vortex/velocity vector ratio is constant. We examine the effect of flow swirling on the intensification of heat transfer under the conditions of the internal problem.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 2, pp. 225–231, February, 1969.     

Numerical simulation of the flow of a supersonic stream of viscous compressible gas over a cavity

Numerical simulation of the flow of a supersonic stream of viscous, compressible, heat-conducting gas over a cavity is carried out on the basis of kinetically consistent difference schemes. Different types of flow (open and closed cavities) are considered, the heat fluxes to the walls of the recess are determined, and a nonsteady regime of flow over a cavity is simulated. The results obtained are compared with known experimental relationships.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 61, No. 4, pp. 570–577, October, 1991.     

The effect of plasma-forming gas flow swirling on the energy characteristics of swirl plasmatrons

We investigate the effect of swirling of a plasma-forming gas on the energy characteristics of two-sided outflow swirl plasmatrons with a “blind≓ tubular and end-wall electrodes. The results obtained indicate the effect of flow swirling on the energy characteristics of the plasmatrons investigated.     

The effect of external convection on freezing in steady turbulent flow in a tube

An analysis is presented of the turbulent flow heat transfer and frozen deposit which occur in a tube that is cooled convectively on its external boundary sufficiently to create an internal frozen layer. The effects of Biot number, Prandtl number and inlet and outside temperatures on the initial freeze-free zone within the tube are shown. Additionally, the thickness profile of the freeze layer and the overall heat transfer rate which occur at steady state are determined and illustrated for a variety of representative cases.     

The interaction between plasma jet of a capillary discharge and transverse supersonic air flow

An experimental investigation is performed of modes of outflow into stationary air and of supersonic flow of a plasma jet developed by a capillary plasma generator. A theoretical model is suggested, which explains the obtained experimental results and enables one to simulate the process of injection of plasma jet into a supersonic air flow. The possibility is demonstrated of using such jets for the ignition of supersonic flows of combustible mixture.     

Calculation of electric arc interaction with a turbulent gas flow

The characteristics of an electric arc in a turbulent gas flow are studied. Relationships for calculating turbulent transport are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 4, pp. 550–557, April, 1988.     

The effect of arbitrarily oriented hot jet on supersonic flow past a blunt body

We present the results of numerical simulations of the flow past a blunt body, from which an oriented thin hot jet of an ideal gas is emitted. The dependences of the flow regime and total aerodynamic characteristics of the blunt body on the angle of hot jet emission have been studied.     

The effect of bubbles on the structure of flow and the friction in downward turbulent gas-liquid flow

Results are given of a numerical study of local structure of downward gas-liquid flow in a vertical pipe. The numerical model is based on the use of two-liquid Eulerian approach. Investigation is performed of the impact made by the variation of the degree of dispersion of the gas phase, volumetric flow ratio of gas, channel diameter, and velocity of the liquid phase on the local structure and skin friction in two-phase flow.     

Interaction between a weak oblique shock wave and a turbulent boundary layer in purely supersonic flow

Summary The paper deals with the interaction of a weak oblique shock and a turbulent boundary layer at a flat plate at purely supersonic speeds. Except for a small region where nonlinear transonic effects are of importance analytical expressions for the pressure- and skin friction distributions are derived.With 6 Figures     

Effect of particle-wall interaction on triboelectric separation of fine particles in a turbulent flow

Triboelectric separation is an effective way to separate fine powders with particle sizes and densities in the same order of magnitude. Many relevant process variables influence the charging behaviour; however, the corresponding effects on the subsequent separation of particles remain unknown. To utilize triboelectric separation as a powerful tool for fine powder separation, process parameters such as the choice of contact wall materials in the charging region have to be investigated. We report for the first time the influence of the tube’s wall material, in which particle charging took place, on triboelectric separation of fine protein-starch mixtures. Different electrically insulating materials along the triboelectric series were tested. No significant influence of the wall material on the separation selectivity and efficiency was found. In addition, particle-wall interaction was inhibited using an experimental setup which allows to control the flow boundary-layer by blowing out air through the tube wall. Also the results obtained by this novel setup showed no significant differences compared to the setup with particle-wall interactions. Additionally, CFD simulations were used to confirm the absence of particle-wall interactions in the boundary-layer control setup. A variation of the boundary-layer thickness leads to a constriction of the particle-containing flow region in the centre of the pipe. Experiments show that this compression of the particle flow zone results in no further increase in selectivity and efficiency of separation. Thus, particle-particle interaction is the prevalent triboelectric charging mechanism of fine powders charged in a turbulent flow regime.     

The effect of clustering of particles on Rayleigh scattering of radiation in a turbulent flow

The effect of clustering of particles under conditions of homogeneous isotropic turbulence on Rayleigh scattering of radiation is analyzed. It is demonstrated that, similarly to the diagnostics of molecular structure of liquid using X-ray scattering, the radial distribution function of macroscopic particles, which characterizes the clustering phenomenon, may be determined by way of measuring the intensity of scattering of infrared or microwave radiation. An approximate relation for clustering coefficient is obtained, which may be employed for estimating the increase in reflected radiation of microwave radar from cumulus clouds owing to turbulent clustering of water drops in the cloud.