Author: Harry PetschekPublisher:
ISBN:
Category : Argon
Languages : en
Pages : 98
Book Description
Approach to Equilibrium Ionization Behind Strong Shock Waves in Argon
Author: Harry PetschekApproach to Equilibrium Ionization Behind Strong Shock Waves in Argon
Author: Harry PetschekPublisher:
ISBN:
Category :
Languages : en
Pages : 72
Book Description
Previous work on strong shock waves in argon has shown that the degree of ionization reaches thermodynamic equilibrium for shock speeds greater than about ten times the speed of sound in room temperature argon. The degree of ionization reaches about 25% at the highest shock strengths available in an ordinary shock tube. This paper reports a detailed theoretical and experimental study of the approach of high temperature argon to this equilibrium degree of ionization. The mechanism for the approach to equilibrium can be divided into two stages. The first, which accounts for about 10% of the final ionization, is apparently controlled by impurities present in the gas even after considerable care is taken to insure high purity. In the second stage ionization by electron-atom collisions becomes dominant. The rate of ionization by this process is limited by the rate of energy transfer to electrons by elastic collisions with the atoms and ions in the gas and is relatively independent of the inelastic ionization crosssection. This rate is calculated and is in agreement with experimental measurements making use of (1) the visible continuum radiation from the gas, and (2) the electrostatic potentials in the gas due to the diffusion of electrons. (Author).
Approach to Equilibrium Ionization Behind Strong Shock Waves in Argon
Author: Harry Ewald PetschekPublisher:
ISBN:
Category : Ionization
Languages : en
Pages : 260
Book Description
Equilibrium Hydrodynamic Variables Behind the Primary and Reflected Shock Waves in Argon and Nitrogen
Author: Norman T. GrierPublisher:
ISBN:
Category : Argon
Languages : en
Pages : 60
Book Description
Experimental Study on the Ionization of Argon Gas in a Non-Equilibrium State Behind Reflected Shock Waves
Author: K. TeraoPublisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
The electron temperature, the density and the ion temperature in argon gas behind reflected shock waves were measured by a laser light scattering method, while the gas temperature was measured by the spectroscopic method. The values of these three temperatures are different from each other during a certain period after arrival of the reflected shock front. Both the electron and ion temperatures are much higher than the theoretical gasdynamic temperature. The ionization rate is also much higher than that in the equilibrium state, but the measured gas temperature is lower than the theoretical one. These results suggest that the argon gas is in a non-equilibrium state during the first period.
Thermal Ionization Behind Strong Shock Waves in Argon
Author: Dennis Martin PhillipsPublisher:
ISBN:
Category :
Languages : en
Pages : 44
Book Description
Photoionization of N2 and O2 Ahead of Strong Shock Waves in a Shock Tube
Author: A. J. MulacPublisher:
ISBN:
Category : Gas dynamics
Languages : en
Pages : 48
Book Description
An improved calculation of photoionizaton ahead of strong shock waves in N2 and O2 has been carried out. In contrast to previous calculations, these calculations include a more detailed kinetic model, a source of finite extent, and wall reflection. Very good agreement (℗± 20%) has been obtained between calculated values of electron density and values measured in the experiments of Presley and Omura.
Initial Ionization Rates in Shock-heated Argon, Krypton, and Xenon
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The rate of ionization behind strong shock waves in argon, krypton, and xenon is observed by a transverse microwave probe, over a range of electron densities low enough that atom-atom inelastic collisions are the rate-determining mechanism. Shocks of Mach number 7.0 to 10.0 propagate down a 2-inch-square aluminum shock tube into ambient gases at pressures of 3.0 to 17.0 mm/Hg, heating them abruptly to atomic temperatures of 5500 to 9600 deg K. The subsequent relaxation toward ionization equilibrium is examined in its early stages by the reflection, transmission, and phase shifts of a 24.0 Gc (1.25 cm) transverse microwave beam propagating between two rectangular horns abreast a glass test section. The data yield effective activation energies of 11.9 plus or minus 0.5 ev for argon, 10.4 plus or minus 0.5 ev for krypton, and 8.6 plus or minus 0.5 ev for xenon. These coincide, within experimental error, with the first excitation potentials, rather than the ionization potentials of the gases, indicating that in this range ionization proceeds via a two-step process involving the first excited electronic states, of which the excitation step is rate-controlling. (auth).
Nonequilibrium Ionization Behind Shock Waves in Argon
Author: R. L. AlpertPhysics of Shock Waves and High–Temperature Hydrodynamic Phenomena
Author: Wallace HayesPublisher: Elsevier
ISBN: 0323147852
Category : Science
Languages : en
Pages : 479
Book Description
Physics of Shock Waves and High-Temperature Hydrodynamic Phenomena, Volume II presents interpretations of the physical basis of shockwaves and high-temperature hydrodynamic phenomena and gives practical guidance to those who work with these subjects in science and modern technology. This volume contains chapters discussing such topics as the shockwave structure in gases; physical and chemical kinetics in hydrodynamic processes; the radiative phenomena in shock waves and in strong explosions in the air; thermal waves and shockwaves in solids; and self-similar processes in gasdynamics. Physicists, engineers, researchers, and professors and students in the field of the physical sciences will find the book very educational.