Thermal Conductivity and Eucken Correction for Diatomic Gases and Binary Gas Mixtures

Srivastava, B. N.; Srivastava, Ritu

doi:10.1063/1.1730155

Cited by 33 publications

(11 citation statements)

References 19 publications

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“…(4) the enthalpy, h(T), is computed using the Shomate interpolation polynomials for molecular nitrogen and oxygen according to the NIST database [26]. Viscosity is modeled using Sutherland's law, assuming a Newtonian fluid with temperature-dependent viscosity, and the conductive fluxes are calculated with temperature-dependent thermal conductivities [27].…”

Section: + ( ) + ( ) = ( ) + ( ) + ( )mentioning

confidence: 99%

Gas dynamics and vorticity generation in laser-induced breakdown of air

Dumitrache¹,

Yalin²

2020

Opt. Express

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Research has shown that the ignition characteristics of laser induced plasmas in fuel-air mixtures are influenced by the gas dynamics effects induced during the gas breakdown stage. Here, we present numerical modeling of the fluid mechanics induced by breakdown (plasma formation) from a nanosecond near-infrared (NIR) laser pulse in air. The simulations focus on the post-discharge kernel dynamics with the goal of developing a better understanding on how vorticity is generated during the kernel cooling phase. Initial conditions (ICs) of kernel shape, temperature and pressure (corresponding to the end of the laser pulse) are found from experimental Rayleigh scattering data. It is shown that this method for determining ICs is preferred versus use of the Taylor-Sedov blast wave theory as it provides a more accurate description of the starting field. Past experimental observations have revealed that the gas dynamics of nanosecond laser sparks typically lead to the formation of an asymmetric torus with a frontal lobe propagating towards the laser source. We show that the development of the asymmetric torus is governed by strong vorticity generated through baroclinic torque arising from the blast wave that forms at the kernel boundary. Initially, the blast takes the shape of the teardrop kernel but then evolves into a spherical front during the first ~10 µs because the blast wave strength varies along its circumference. This spatial variation leads to a misalignment between the pressure and density gradients and generation of vorticity by baroclinic torque. Ultimately, the observed flow-field is dictated by how the energy was initially deposited around the beam waist during breakdown. As such, one can tailor the aerodynamics induced during the cooling and recombination phase by controlling the energy deposition profile.

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Section: + ( ) + ( ) = ( ) + ( ) + ( )mentioning

confidence: 99%

Gas dynamics and vorticity generation in laser-induced breakdown of air

Dumitrache¹,

Yalin²

2020

Opt. Express

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“…The underlying assumption is that the transport of kinetic energy is unaffected by the internal degrees of freedom, meaning that an exchange of energy between the internal and translational energy only occurs rarely. This assumption has been supported by experimental investigations [16]. For reasons of simplicity, Eucken has weighted the internal degrees of freedom with a factor f int = 1 [16,17].…”

Section: Eucken Correctionmentioning

confidence: 87%

“…This assumption has been supported by experimental investigations [16]. For reasons of simplicity, Eucken has weighted the internal degrees of freedom with a factor f int = 1 [16,17].…”

Section: Eucken Correctionmentioning

confidence: 87%

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Precise determination of LJ parameters and Eucken correction factors for a more accurate modeling of transport properties in gases

et al. 2020

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The kinetic gas theory, in particular the equations of Chapman and Enskog, proved to be good and widely applicable approximations for modeling transport properties like diffusion coefficients, viscosities and thermal conductivities. However, these equations rely on at least the Lennard-Jones parameters and for polar gases also the dipole moment. In the scientific literature, the Lennard-Jones parameters are fitted to only one experimentally determined transport coefficient. This approach leads to good agreement between the Chapman Enskog equations employing the so obtained parameters with the experimental data for this specific transport property. However, utilizing the same parameters for modeling different transport properties oftentimes leads to distinct deviations. In this work, it is shown that the subset of Lennard-Jones parameters with which the Chapman Enskog equations can predict the experimental results with deviations comparable to the experimental uncertainty are not identical for each transport property. Hence, fitting towards one property doesn't necessarily yield parameters that are suited to describe the other transport properties. In this publication, the Lennard-Jones parameters and a temperature dependent Eucken correction factor, leading to a significantly higher accuracy than the classical Eucken correction and also its modification by Hirschfelder, are therefore fitted towards all three transport properties simultaneously for seven exemplary gases. This approach leads to a significantly better agreement with experimental data for the three transport properties than the classical approach that relies on fitting to one single transport property and can be utilized to determine accurate sets of Lennard-Jones parameters and Eucken correction factors for any gas species. It provides a computationally inexpensive and practical method for the precise calculation of transport properties over a wide range of temperatures relevant for processes in the chemical industry.

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“…This leaves just those soft degrees of freedom, which do contribute to the heat transport at the room temperature. The problem of energy transfer between translational and internal degrees of freedom in gases has been discussed in literature before and has been known as Eucken correction (78). In case of molecular liquids and polymers translational and internal degrees of freedom cannot be separated.…”

Section: Force Field Considerations For the Calculation Of Thermal Comentioning

confidence: 99%

Molecular Dynamics Calculations of the Thermal Conductivity of Molecular Liquids, Polymers, and Carbon Nanotubes

Algaer

Müller‐Plathe

2012

Soft Materials

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Thermal Conductivity and Eucken Correction for Diatomic Gases and Binary Gas Mixtures

Cited by 33 publications

References 19 publications

Gas dynamics and vorticity generation in laser-induced breakdown of air

Gas dynamics and vorticity generation in laser-induced breakdown of air

Precise determination of LJ parameters and Eucken correction factors for a more accurate modeling of transport properties in gases

Molecular Dynamics Calculations of the Thermal Conductivity of Molecular Liquids, Polymers, and Carbon Nanotubes

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