Quantum effects in rotational relaxation of a freely expanding gas

Lebed, I. V.; Ryabov, V. V.

doi:10.1007/bf00908124

Cited by 13 publications

(24 citation statements)

References 5 publications

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“…Lebed and Riabov [15] and Riabov [16] studied another cause for the rotational energy departure. At the decrease of kinetic temperature T t , the Messy adiabatic parameter [17], which describes energy transfer between highly excited rotational levels unable to relax, becomes larger than unity.…”

Section: Rotational Relaxation In Freely Expanding Gas Flowsmentioning

confidence: 99%

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Estimations of Rotational Relaxation Parameters in Diatomic Gases

Riabov¹

2011

AIP Conference Proceedings

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The problem of redistribution of translational and rotational energy has been solved for diatomic gases within the framework of the Chapman-Enskog method and the Parker model in the general case of the arbitrary energy exchange ratio. The nonequilibrium gasdynamic equations, transport coefficients and relaxation time have been found for rotational-translational processes in a diatomic gas. The calculations of relaxation time, viscosity, thermal conductivity, and diffusion coefficients are carried out in the temperature range from 200 K to 10,000 K for nitrogen. The calculated parameters and coefficients are compared with the values obtained by the Mason-Monchick approximate method as well as data from experiments in ultrasonic, shock-wave, and vacuum devices. The correlation of the theoretical and experimental data is satisfactory. The applicability of one-and two-temperature relaxation models is discussed. The numerical solutions of the obtained system of the Navier-Stokes equations are analyzed for the cases of nitrogen flow in underexpanded jets and supersonic rarefied gas flow near a sphere.

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Section: Rotational Relaxation In Freely Expanding Gas Flowsmentioning

confidence: 99%

“…Using the technique of Lebed and Riabov [15], the rotational-translational relaxation times were calculated for nitrogen at stagnation temperature T 0 = 290 K [see Fig. 3 (left)] under the conditions of aerodynamic experiments in the underexpanded jets [13], [14], [16].…”

Section: Rotational Relaxation In Freely Expanding Gas Flowsmentioning

confidence: 99%

Estimations of Rotational Relaxation Parameters in Diatomic Gases

Riabov¹

2011

AIP Conference Proceedings

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“…In the simulation of these flow regimes in wind tunnels, especially in experiments using underexpanded jets, the gas flow which encounters the model may be strongly nonequilibrium [3], the relation ~R~ > Tt~ holding. The "separation" of the rotational temperature of the gas from the kinetic temperature is, on the one hand, a consequence of the pronounced reduction in the density of the gas downstream, which leads to a reduced number of collisions undergone by individual molecules, and, on the other, can be explained by the manifestation of quantum effects following the abrupt lowering of the kinetic temperature in the flow.…”

Section: The Changes In the Internalmentioning

confidence: 99%

“…For heavy molecules, the characteristic relaxation times of the rotational degrees of freedom are short [6,7], so that at small [6,7], and at very low temperatures with allowance for the departure from equilibrium in the oncoming flow and quantum effects [3].…”

Section: The Changes In the Internalmentioning

confidence: 99%

“…In the experimental simulation of these flow regimes in wind tunnels, the nonequilibrium nature of the energy transfer must always be taken into account [2,3]. The nonequilibrium excitation of the rotational degrees of freedom of the molecules can lead to an increase in the translational temperature and the thickness of the disturbed zone compared with the equilibrium case [4,5].…”

Section: An Influencementioning

confidence: 99%

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