Analysis of the process of mixing of a passive impurity in a jet mixer

The experimental results for two regimes of mixing of a passive impurity in an axisymmetric jet mixer — the mixing of a turbulent jet and a cocurrent flow to form a recirculation zone behind the nozzle and an analogous mixing without the formation of a recirculation zone (Re_d = 10,000) — have been presented. The velocity field has been measured in the mixer cross sections at different distances from the nozzle (0.1 < x/D < 9.1) with a one-component Doppler laser anemometer, whereas the scalar field (concentration of the passive impurity) has been diagnosed by the laser-induced fluorescence method. Based on the scalar distributions obtained, the autocorrelation function and the integral scale have been computed, the form of the probability density function has been restored, and the distributions of the asymmetry and excess coefficients have been constructed. Visualization of flow in the mixer has been carried out. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 46–59, March–April, 2007.     

Distribution of disperse impurity in turbulent jet

The concentration fields of disperse impurity are calculated on the basis of a k- model of turbulence in a wide range of Stokes numbers.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 4, pp. 548–555, October, 1985.     

Loss of a passive impurity in a turbulent vortex ring

A diffusion boundary-layer approximation is used to obtain an analytic solution to the problem of the loss of a passive impurity by a turbulent vortex ring.Translated from Inzhenerno-Fizlcheskii Zhurnal, Vol. 50, No. 1, pp. 31–39, January, 1986.     

Diffusion-migration description of finely dispersed impurity propagation in a turbulent jet

Computations of the scattering of a finely dispersed impurity in a submerged jet are performed on the basis of a model taking account of turbulent diffusion and turbulent migration together.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 59, No. 4, pp. 609–614, October, 1990.     

Length-scale distributions of the concentration pulsations of a passive impurity in a homogeneous turbulent flow

A relation for calculating the probability density function f _t ^λ (ϕ) of the length scales of a passive concentration field in homogeneous turbulence has been obtained by consideration of the joint statistics of the concentration field and its gradient. The closed equation derived for f _t ^λ (ϕ) has been solved numerically using the data of direct numerical modeling of homogeneous turbulence for the mean characteristics involved in the equation as the coefficients. The results obtained for different values of the Schmidt number have been compared. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 6, pp. 131–142, November–December, 2005.     

Modeling the field of a passive scalar in a nonisothermal turbulent plane gas jet

On the basis of a second-order correlational model of turbulence and an effective numerical algorithm, the problem of the distribution of thermal characteristics in a plane nonisothermal turbulent gas jet is solved.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 3, pp. 387–393, March, 1988.     

Numerical and experimental study of a nonisothermal turbulent jet with a heavy impurity

Temperature and momentum distributions of the carrier phase are determined experimentally and compared to results of numerical calculations using the (k–) model.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 50, No. 5, pp. 735–743, May, 1986.     

Utilization of model passive impurity concentration distribution functions to compute turbulent flow radiation

The adequacy of different semi-empirical methods of taking account of passive impurity concentration fluctuations is investigated for numerical modelling of radiating turbulent flows on the basis of comparisons between computed and measured energetic brightness fields.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 57, No. 3, pp. 375–382, September, 1989.     

Experimental investigation of a turbulent jet in turbulent cross flow

The characteristics of an axisymmetric turbulent jet propagating in a cross flow with a high degree of turbulence are investigated experimentally.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 43, No. 2, pp. 225–228, August, 1982.     

Evaluation of the mixing effectiveness of a new powder mixer

The effectiveness of the new powder mixer Canguro J tumbler was evaluated using lactose, microcrystalline cellulose, and salicylic acid as chemical indicator with the ratio 88:10:2 (w/w). The mixing time, the speed of the tumbler (rpm), its inclination, and filling percentage were varied in order to assess the limits of the mixer and the best parameters to use for obtaining a mixture as uniform as possible. The same experiments were then repeated after addition of 1% (w/w) magnesium stearate to the mixture of powders. The efficiency in the distribution of this lubricant was estimated by the progressive hardness reduction of the tablets derived from the compression of the powders, at a constant applied force. Finally, a comparison between Canguro J and a very efficient V-shaped mixer of the same capacity was performed. The results show that all investigated parameters influenced the mixing capability of Canguro J. The best effectiveness of the mixer occurred at the filling rate of 50% and a rotation speed of 20 rpm; in this case, Canguro J is even a little more effective than the V-shaped mixer. However, even at the filling rate of 70%, the same distribution uniformity of the powders can be obtained after a mixing time protraction of a few minutes.     

Simulation of a subsonic isothermal turbulent submerged jet flowing from an annular nozzle

A simulation of the flow in a jet has been carried out with the use of the Reynolds-averaged, space-filtered Navier-Stokes equations closed by the k-ε model of turbulence and the subgrid RNG model of eddy viscosity. The results of calculations carried out on the basis of the k-ε model and the results of simulation of large vortices are in quantitative and qualitative agreement with the corresponding measurement data, which is evidence in favor of the main laws defining the decay of the gas-dynamic behavior of cold-gas submerged jets and the fluctuations of their parameters. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 2, pp. 312–320, March–April, 2008.     

A circular turbulent jet in a crossflow

An integral method is proposed for calculating a circular turbulent jet propagating in a crossflow. The jet parameters obtained by a numerical method for different values of ¯q were compared with experimental data. Satisfactory agreement between the sets of data was found.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 42, No. 4, pp. 548–554, April, 1982.     

Evaporation in a free turbulent air-droplet jet

It is shown that under certain conditions the rate of evaporation of a liquid is determined not by the evaporation kinetics of the individual droplets but by the rate of diffusion of outside air into the jet as a whole.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 3, pp. 423–426, March, 1971.     

Noise intensity in the field of a subsonic turbulent jet

Results are shown of digital-computer calculations pertaining to the acoustic properties of subsonic jets, by a method proposed earlier in [1, 2]. The gasdynamic and turbulence parameters of a jet, needed for calculating the acoustic radiation, have been determined before-hand.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 24, No. 2, pp. 282–289, February, 1973.     

Optical properties of a planar turbulent jet

A planar heated air jet was constructed. Its flow properties were characterized and shown to be both reproducible and in good agreement with the results of turbulence theory. The optical properties of the jet were studied with the help of a 632.8-nm He-Ne laser beam. The random phase modulations imposed on the wave front of the beam traversing the jet were measured by interferometric means, and their spectra and variance were determined. The one-dimensional phase fluctuation spectrum obeyed a -8/3 power law as predicted by theory, whereas the phase variance (?(2)) depended on the jet temperature and was studied for values to as high as 0.4 (rad)(2)).     

A turbulent electric arc in a submerged jet

We have experimentally investigated the optical and electrical characteristics of a turbulent electric arc burning at the axis of a submerged jet.Translated from Inzheherno-Fizicheskii Zhurnal, Vol. 57, No. 4, pp. 533–538, October, 1989.     

Flow generated in the ambient medium by a turbulent jet

A solution is obtained to the problem of calculating the flow induced in the ambient medium by a plane jet expelled from a nozzle of finite dimensions. The theoretical results are in satisfactory agreement with the experiment.Translated from Inzhenerno-Pizicheskii Zhurnal, Vol. 15, No. 5, pp. 836–842, November, 1968.     

Discharge of a turbulent jet in a monodisperse fluidized bed

The velocity of initial circulation is calculated and explanations are given for the mechanism of jet collapse and the existence of bubble and jet regimes.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 43, No. 6, pp. 913–918, December, 1982.     

Diffusion of inertial particles in a turbulent gas jet

An algorithm is proposed and a mathematical experiment is performed on the diffusion of high-density particles in a turbulent gas jet. The problem is solved with the impurity particle action on the carrier phase characteristics taken into account.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 57, No. 3, pp. 367–375, September, 1989.     

Numerical study of the mixing process of binary-density particles in a bladed mixer

Discrete element method (DEM) simulations of binary mixing of particles with different densities were conducted to study the influence of density ratio, blade speed, and filling level on the particle dynamics and mixing performance in a bladed mixer. Four particles with different densities at different locations were tagged to discuss the influence of three factors on the particle trajectory and velocity field in the mixer. A method based on cubic polynomial fitting of relative standard deviation was used to determine the critical revolution during the mixing process. It was found that the non-dimensional tangential velocity decreases with the increase of the blade speed and filling level, the fluctuation of vertical velocity increases with the radial location, blade speed, and filling level, and it is more pronounced than the fluctuation of tangential and radial velocity during the mixing process. Results obtained indicate that the mixing performance of particles with different density increases with the decrease of density ratio and filling level, while it increases with the increase of blade speed.