Shift of chemical equilibrium in a resonance infrared radiation field

The degree of displacement of chemical equilibrium in dissociation reactions, including three-particle recombination due to laser radiation at an isolated vibrational degree of freedom of the molecules, is determined. Dependences of the vibrational temperature and the chemical equilibrium constant on the vibrational excitation probability are obtained.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 1, pp. 10–12, January–February, 1976.The authors wish to express their appreciation to R. V. Khokhlov for support and interest in the work.     

Explosion and implosion in a mixture of chemically reacting ideal gases

Summary A chemically reacting mixture of ideal gases is herein called a Stokes mixture — not of necessity a mixture of Stokes fluids although such are included — if the shear and bulk viscosities never contribute to the internal energy of the mixture when the constituents are undergoing dilatational motions. The mechanical and thermal features of these motions in a general binary mixture of chemically reacting ideal gases are studied.

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Sommario Una miscela chimicamente reagente di gas ideali è qui chiamata una miscela di Stokes — non necessariamente una miscela di fluidi di Stokes, anche se questo caso vi è compreso — se le viscosità di scorrimento e di dilatazione non contribuiscono mai alla energia interna della miscela quando i costituenti sono soggetti a moti dilatazionali. Si studiano le caratteristiche meccaniche e termiche di questi moti in una generale miscela binaria di gas ideali chimicamente reagenti.

     

Shock wave structure in a binary mixture of viscous gases

Shock wave structure was studied in [1] using Struminskii's model [2] with the assumption that viscosity and thermal conductivity exist only as interactions between components. The present study will obtain asymptotic solutions of the problem of shock wave structure in the Navier-Stokes approximation.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 5, pp. 48–54, September–October, 1984.     

An exact solution of the navier-stokes equations for a chemically reacting mixture of gases

An exact solution of the Navier-Stokes equations is presented for the flow of a viscous heat-conducting chemically reacting mixture of gases in a two-dimensional expanding channel. The conditions for the existence of an exact solution of the source type are: the chemical reactions must be equimolecular in an equilibrium mixture of gases, and they must be second order forward and backward in a nonequilibrium mixture. Numerical results are obtained for the flow of a four-component equilibrium mixture of gases in a two-dimensional nozzle for various Mach numbers (M) and Reynolds numbers (Re).Translated from Zhurnal Prikladnoi Mekhanika i Tekhnicheskoi Fiziki, No. 4, pp. 49–56, July–August, 1973.     

The evaporation–condensation problem for a binary mixture of rarefied gases

Continuum Mechanics and Thermodynamics - Half space problems of evaporation and condensation for a binary mixture of inert gases are investigated when the dynamics is governed by a system of...     

Couette flow of a binary mixture of rigid-sphere gases described by the linearized Boltzmann equation

A concise and accurate solution to the problem of plane Couette flow for a binary mixture of rigid-sphere gases described by the linearized Boltzmann equation and general (specular-diffuse) Maxwell boundary conditions for each of the two species of gas particles is developed. An analytical version of the discrete-ordinates method is used to establish the velocity, heat-flow, and shear-stress profiles for both types of particles, as well as the particle-flow and heat-flow rates associated with each of the two species. Accurate numerical results are given for the case of a mixture of helium and argon confined between molybdenum and tantalum plates.     

The speed of sound in a reacting gas mixture

The one-dimensional problem of the propagation of sound in a two-component mixture is solved. An expression is obtained for the speed of sound under conditions of chemical equilibrium. The results for the dissociation of hydrogen are compared with similar results in [1].     

Direct numerical solution of the Boltzmann equation for a relaxation problem of a binary mixture of hard sphere gases

Summary The aim of the paper is the presentation of results obtained by the direct numerical solution of the Boltzmann equation in the case of a binary mixture of hard sphere gases. The system of two coupled Boltzmann equations is solved by a techique combining finite differences with the Monte Carlo evaluation of the Boltzmann collision integrals. It is shown how the technique proposed by Aristov and Tcheremissine for a single gas can be extended to a mixture. The resulting algorithm can be very well vectorized and the results of a few test calculations on the vector computer CRAY-XMP 48 are presented.

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Sommario Il presente articolo si propone la descrizione di alcuni risultati relativi ai fenomeni di rilassamento omogeneo in una miscela binaria di sfere rigide. Il sistema di equazioni di Boltzmann che regge l'evoluzione temporale delle funzioni di distribuzione dei gas componenti viene risolto numericamente con un metodo che combina l'uso di differenze finite con la valutazione dell'integrale di collisione mediante un inetodo di Monte Carlo. La tecnica presentata costituisce per alcuni aspetti la generalizzazione di quella proposta da Aristov e Tcheremissine per un singolo gas. Si evidenzia inoltre come l'algoritmo sia di per sè in massima parte vettorizzabile e si presentano alcuni risultati ottenuti sull'elaboratore vettoriale CRAY-XMP48.

     

The development of volumetric failure in silicate glasses and polymers under the action of laser radiation

A investigation was made of volumetric failure in silicate glasses K-8 and F-5 and in polymethylmethacrylate (PMMA), and the energy-time characteristics were recorded for the start of the stage of the formation of damage in these materials due to a laser beam. The article discusses a model of the failure of silicate glasses as a result of the absorption of light at microdefects, as well as a model of the formation of cracks from high-temperature sites in polymers, taking account of the durability of the material. An evaluation is made of the power density q and the energy in the proposed mechanisms for the failure of transparent dielectrics.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 138–145, July–August, 1972.In conclusion the authors thank A. E. Kuznetsov for his part on posing the problem, and V. F. Loskutov and L. N. Nefedov for their help in the experiments.     

Effect of viscosity on the autoignition of a reacting moving mixture

Ya. B. Zel'dovich has established [1] that in a continuous-flow reactor two ignition regimes are possible: forced ignition and autoignition.It is important to consider the special properties of the autoignition regime associated with the hydromechanics of laminar flow and heat transfer through the pipe wall. In [2, 3] it was shown that the effect of heat of friction on heat transfer in long pipes is qualitative in character. Moreover, according to Schlichting [4], in certain cases the temperature gradient for such flows due to the heat of friction may reach 10–30°, which is comparable with the preexplosion temperature rise in the stationary theory of thermal explosion [5]. In this connection it is clear that under certain conditions the heat of friction may considerably reduce the explosion limit.This paper is devoted to a study of the effect of heat of friction on the explosion limit of a reacting fluid in a long cylindrical pipe. The dynamic autoignition regime due to heat of friction is examined. In particular, it is established that, other things being equal, by increasing the pressure drop it is possible to obtain explosion of the reacting system.     

Approximate method for solving the kinetic equation for moderately dense gases near a boundary. Slip of a binary mixture

The problem of the slip of a binary gas mixture of moderate density along a flat surface is considered. A solution is obtained by a modification of Maxwell's method by means of the Enskog-Thorne kinetic equations for dense gases. The velocities of isothermal, thermal, and diffusion slip for rarefied and moderately dense binary mixtures are compared.     

Dynamics of a bubble in a liquid under laser pulse action

Simulation was performed of the behavior of a vapor bubble in a liquid under laser irradiation in laboratory experiments. A mathematical model was developed to analyze the effect of heat conduction, diffusion, and mass transfer on the bubble dynamics under compression and expansion. It is found that at the stage of collapse, intense condensation occurs on the bubble wall, which results in a significant (more than 15fold) decrease in bubble mass and an increase in pressure (to 10⁵ atm) and temperature (to 10⁴ K(. Results of numerical calculations of the radius of the first rebound and the amplitude of the divergent shock wave in water are compared with experimental data. It is shown that small (:about 1%) additives of an incondensable gas lead to a considerable decrease in mass transfer on the bubble wall.