Unsteady heat transfer of a monatomic gas between two coaxial circular cylinders
We consider a kinetic-theory treatment of the cylindrical unsteady heat transfer. A model kinetic equation of the BGK (Bhatnager-Gross-Krook) type is solved using the method of moments with a two-sided distribution function. We study the relations between the different macroscopic properties of the gas as the temperature, density, and heat flux with both the radial distance r and the time t. Also we study the problem from the viewpoint of irreversible thermodynamics and estimate the entropy, entropy production, entropy flux, thermodynamic forces, kinetic coefficients, the change in internal energy, and verify Onsager′s relation for nonequilibrium thermodynamic properties of the system.
Kinetic and thermodynamic treatment for the exact solution of the unsteady Rayleigh flow problem of a rarefied homogeneous charged gas
This article presents an exact and enhanced solution of the study in the previous paper [Can. J. Phys., 88 (2010), 501‐511]. For this purpose, I use the traveling wave solution method instead of the small parameter method, which enables us to have the full exact solution without any cut-off from the value of variables. In addition, I use the accurate formula of the electron‐ electron collision frequency. I persist in avoiding the discontinuity in the solution caused by the Laplace transformation results, which is included in the previous study. In the present work, the kinetic and the irreversible thermodynamic properties of the charged gas are presented from the molecular viewpoint. Our study is based on the solution of the BGK (Bhatnager‐ Gross‐Krook) model of the Boltzmann kinetic equation, with the precision value of the electron‐electron collision frequency. The BGK model equation coupled with Maxwell’s equations for electrons near a moving rigid plane are solved. The distinction and comparisons between the perturbed and the equilibrium velocity distribution functions are illustrated. The ratios between the different contributions of the internal energy changes are predicted via the extended Gibbs equation for both diamagnetic and paramagnetic plasmas. The results are applied to a typical model of laboratory
Prediction of net pressure on pressure equalized cavities
Abstract A numerical model has been developed for prediction of net pressure on pressure equalized cavities. The results based on this model show good agreement with those obtained from mock-up tests. Parametric studies verify that reductions in cladding load are possible, with proper design of curtain walls.