The application of weighting schemes in the statistical modelling of flows of a multicomponent gas to the calculation of the structure of a shock wave

Genich, A. P.; Kulikov, S. V.; Манелис, Г. Б.; Serikov, V. V.; Yanitskii, V. E.

doi:10.1016/0041-5553(86)90164-3

Cited by 7 publications

(4 citation statements)

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“…MODELING TECHNIQUE The calculations were carried out by the Monte Carlo method of nonstationary statistical modeling, founded by Bird [16]. The modeling technique is presented in [17,18]. However, for the convenience of the reader, its main points will be summarized below.…”

Section: Resultsmentioning

confidence: 99%

“…It is explained by the deviation of the fluxes of matter, momentum, and energy across the boundaries from their theoretical values at infinity, probably due to the statistical fluctuations due to the insufficient number of model particles and the size of the simulation area. To stabilize the position of the SW front, we used the procedure for regulating the number of particles of the most representative component introduced in the model region (Н 2 ) [18]. In all the variants of modeling considered below, it provided an almost stationary position of the wave for some time of the calculation.…”

Section: Resultsmentioning

confidence: 99%

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Dependence of the Knock Threshold of an H2-Air Mixture With Small Xe Additives

Atanov

Ezhov

Kulikov

et al. 2021

Russ. J. Phys. Chem. B

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The effect of a small addition of Xe on the conditions for the occurrence of detonation in an incident shock wave (SW) with a change in its intensity is studied. The experiments are carried out in a shock tube (ST) with mixtures (75 -q)% H 2 + 25% air + q% Xe, where q = 0, 0.25, and 0.5. The addition of Xe leads to a shift in the detonation threshold to the region where the conditions are more unfavorable for its occurrence. Moreover, decreasing x from 0.5 to 0.25 causes a stronger shift in the detonation threshold; i.e., dependence x became nonmonotonic. This effect is due to a strong increase in the frequency of high-energy collisions of O 2 and Xe in the front compared to the equilibrium behind the wave and the subsequent significant acceleration of the chemical interaction of O 2 and H 2 behind the front. It is a consequence of the occurrence of a specific translational nonequilibrium in the wave front. This is indicated by the results of similar studies of the effect of replacing a small amount with an inappropriate amount of Xe on the conditions for the onset of detonation for mixtures of 10% H 2 + 5% O 2 + 85% He. In addition, the results of the performed numerical simulation with mixtures (75 -q)% H 2 + 25% air + q% Xe (q = 0.25, 0.5), taking into account the rotational relaxation of О 2 and N 2 for conditions close to the conditions of the aforementioned experiments, showed the possibility of a nonmonotonic shift of the detonation threshold.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Dependence of the Knock Threshold of an H2-Air Mixture With Small Xe Additives

Atanov

Ezhov

Kulikov

et al. 2021

Russ. J. Phys. Chem. B

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“…The DSMC method described in [5][6][7] and based on the principle of splitting of molecular motion and intermolecular collisions developed in [8] is used in the present computations. The following modeling procedure is used.…”

Section: Introductionmentioning

confidence: 99%

“…When the partition is instantaneously removed, the gas moves into the latter domain. Simulations are performed in the time interval when the molecules have not yet reached the end of part B of the channel.The DSMC method described in [5][6][7] and based on the principle of splitting of molecular motion and intermolecular collisions developed in [8] is used in the present computations. …”

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confidence: 99%

Translational nonequilibrium of a gas flow into vacuum in a constant-section channel

Kulikov

2006

J Appl Mech Tech Phys

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A single-species gas flow into vacuum in a constant-section channel is computed by means of the Direct Simulation Monte Carlo method. It is shown that the longitudinal, transverse, and total kinetic temperatures are significantly different in the head part of the flow, which is a consequence of the arising translational nonequilibrium. The flow is almost self-similar in the entire region of flow expansion (except for distributions of the transverse and total kinetic temperatures in the head part of the gas flow), which allows one to predict flow parameters at times greater than those used in simulations. Introduction.Obviously, there is no clear physical boundary between matter and vacuum in the case of a gas flow into vacuum, whereas such a boundary is used in solving the present problem at the macroscopic level by hydrodynamic methods. In addition, the distribution of molecules in terms of translational degrees of freedom in the head part of the gas flow may differ from the Maxwellian distribution. The flow in a constant-section channel is numerically examined in the present work with the use of direct statistical Monte Carlo (DSMC) method. It should be noted that this method actually allows obtaining a solution of the Boltzmann equation without solving the latter. Moreover, the DSMC method can be used for simulating steady flows formed when a steady state is reached.The main challenge of the present work is to check self-similarity and to study the translational nonequilibrium of the head part of the gas flow into vacuum in a constant-section channel.There are many papers dealing with exhaustion of gases into vacuum, but most of them consider different conditions of gas expansion. Only papers [1-3] should be noted. The flow in a constant-section channel was considered in [1, Sec. 99, Problem 2], but this was done at the macroscopic (hydrodynamic) level. Results of statistical simulation of the collisions of gases are also presented in [2,3]. Before the collisions of flows, the problem coincides with that considered in the present paper, but this stage of evolution of the gas system is given little attention in [2,3]. It should be noted that the problem of a gas flow into vacuum in a constant-section channel is similar in many aspects to the problem of unsteady evaporation into vacuum from a flat surface (see, e.g., [4]). Formulation of the Problem and Simulation Technique.We consider a one-dimensional flow of a single-species gas without internal degrees of freedom in a one-dimensional space of coordinates (the channel has a large constant cross section, and the influence of the side walls is ignored). The gas is initially located in part A of the channel separated by a partition from vacuum located in part B of the channel. When the partition is instantaneously removed, the gas moves into the latter domain. Simulations are performed in the time interval when the molecules have not yet reached the end of part B of the channel.The DSMC method described in [5][6][7] and based on the principle of splitting of mol...

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