The advantages of utilizing chemical reactions to support laser emission have been recognized for several years. However, a central problem identified in a variety of cw chemical mixing lasers is the dominance of gas-dynamics on the character of the flowing active medium, pointing to the need for a theoretical model that couples the effects of fluid mechanics of mixing with the nonequilibrium kinetics and the cascade of vibrational-rotational laser transitions. As one of the efforts to meet this need, a two-dimensional, rate equation model has been developed. A detailed discussion of the computer model is presented, as well as sample calculations for a representative "cold reaction" HF laser. Comparisons are made with experiment where appropriate.
Nomenclature
C k= mass fraction of species k c p = specific heat at constant pressure D k = laminar diffusion coefficient for species k A£y = activation energy for reaction j E r = rotational-state energy-specific total enthalpy including heats of formation h k = specific enthalpy of species k A/i k = heat of formation for species k AHj = heat of reaction for reaction j k = Boltzmann's constant, chemical rate coefficient, thermal conductivity K =V-TorV-V rate coefficient L = active optical path length Le -Lewis number = (D k + e d )/(/c + K) m -velocity ratio between primary and secondary m -mass flow rate m k -mass of one molecule of species k M -Mach number n -density ratio between primary and secondary n k *= number density of species k n v = number density of emitter molecules in vibrational state v n v>J -number density of emitter molecules in vibrational state v and rotational state J p = pressure p 0 = total pressure •p, -Prandtl number = c p (n + e)/(/c + /c) q = volumetric rate of heat addition to the gas mixture g rad = volumetric rate of radiative energy emission g rot = rotational partition function R = specific gas constant t R v , v +1 = matrix element for the radiative transition v +1 -> v r^r 2 = reflectivities of left and right mirrors i -time T = static temperaturePresented as Paper 74-224 at the AIAA 12th Aerospace Sciences = total temperature u = velocity in x (flow) direction
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.