Numerical modelling of fast-flow CO<sub>2</sub>lasers. I. The model

Rudolph, Rainer; Harendt, Andreas; Bisin, P.; Gundel, Hartmut

doi:10.1088/0022-3727/26/4/006

Cited by 16 publications

(9 citation statements)

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“…These equations can be described by the conservation laws of mass, momentum, and by the equation of state for an ideal gas in one-dimension (assuming that the gas mixture motion is in the x direction) written in differential form as follows [3,6]:…”

Section: Article In Pressmentioning

confidence: 99%

“…During the past years, many papers on the subject of FAF lasers have concerned the modeling of laser processes in the lasing medium [1][2][3][4][5][6]. For example, the work of Sazhin et al [1,2] was concerned with three-temperature approximation; they predicted the development of the velocity profile and the gradual increase in T 1 , T 3 and T 4 along the laser.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of a fast-axial-flow CW CO2 laser

Jelvani

Saeedi

2008

Optics & Laser Technology

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Section: Article In Pressmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical investigation of a fast-axial-flow CW CO2 laser

Jelvani

Saeedi

2008

Optics & Laser Technology

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“…[7][8][9][10][11][12][13][14][15] The earliest research on computer modeling of a gas laser is Smith and Thompson. 7 Then Beverly proposed the six-temperature Boltzmann-equilibrium kinetics model.…”

Section: Introductionmentioning

confidence: 99%

“…10 Rudolph et al presented a complete integration of the onedimensional (1-D) equations of a continuous wave (cw) CO 2 laser plasma with fast turbulent motion. 11 Sazhin et al studied the three-temperature model by computations and available experimental data. 12,13 Al-Hawat and Al-Mutaib proposed a four-temperature model using the Runge-Kutta method.…”

Section: Introductionmentioning

confidence: 99%

Kinetic modeling and optimum design of the discharge tube for the CO<sub>2</sub> laser with computational fluid dynamics method

Huang

Wang

2010

Opt. Eng

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The performance of a high-power fast-axial-flow CO 2 laser is directly determined by the characteristics of the turbulent flow of the active medium in the discharge region. To research the influence of the discharge tube structure on the internal gas flow field and determine the optimum design of the discharge tube, we use the computational fluid dynamics method and a set of governing equations to predict and compare the internal gas flow field of various sizes of discharge tubes. The influence of the tube diameter and gas inflow opening size on the gas flow velocity and turbulence intensity is discussed. There is good agreement between the theoretical prediction and the experimental results. The results obtained provide a basis for the optimum design of a high-power industrial fast-axial-flow CO 2 laser. C 2010 Society of Photo-Optical Instrumentation Engineers.

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“…In the literature (see, e.g, [4][5][6][7][8][9][10][11][12][13]), quantities that are called the occupation numbers of modes e i or the numbers of vibrational quanta in a mode per molecule are used. In this case, each of the vibrational modes of the CO 2 molecules is considered as an independent harmonic oscillator, so that for the quantities e 1 -e 4 the following expressions are used:…”

Section: Introductionmentioning

confidence: 99%

Vibrational kinetics of the active media of CW CO2 lasers

Невдах

Ganjali

2005

J Appl Spectrosc

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The vibrational kinetics of CW CO 2 lasers has been analyzed within the framework of a temperature model. The necessity of taking into account the coupling of the vibrational modes of the CO 2 molecule in determining the occupation numbers and the store of vibrational energy in individual modes is shown. Expressions that connect vibrational temperatures with the rates of excitation and relaxation of the lower vibrational levels of modes have been obtained. The ratios between the vibrational temperatures on selective excitation of the 00 o 1 level and on excitation of CO 2 molecules in an electric discharge as well as the character of the dependences of vibrational temperatures on the pumping-energy value are discussed. Introduction.The most widespread mathematical model used for calculating the energy and spectral characteristics of continuous wave and pulsed (with pulse duration longer than 10 −6 sec) CO 2 lasers is a temperature model. Physically, the model is based on the "hierarchy" of relaxation times that is typical of the CO 2 molecule under the conditions of an active medium:are the times of rotational-translational, vibrational-vibrational intramode, vibrational-translational, and vibrational-vibrational intramode relaxation, respectively (see, e.g., [1][2][3][4]). Within the framework of the temperature model, the vibrational modes ν 1 , ν 2 , and ν 3 of the CO 2 molecules and ν 4 of the N 2 molecules are considered as simple harmonic oscillators. The distributions of populations over the vibrational levels of each of these modes are described by the Boltzmann distributions with vibrational temperatures T i (i = 1, 2, 3, 4). Knowing the vibrational temperatures, it is possible to determine the population of any vibrational level of the CO 2 and N 2 molecules and also the stores of vibrational energy in their modes. The main drawback of this approach is that the vibrational modes of the CO 2 molecule are considered as independent modes, whereas the vibrational temperatures of these modes are regarded as independent parameters.In the present work, within the framework of the temperature model we analyze the vibrational kinetics of continuously pumped CO 2 lasers taking into account the fact that because of the coupling of the vibrational modes of the CO 2 molecule the vibrational temperatures are not independent parameters.Occupation Numbers of the Vibrational Modes of the CO 2 Molecule. In the temperature model the vibrational temperatures of the CO 2 and N 2 molecules are determined [1-4] from the conditions

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Numerical modelling of fast-flow CO₂lasers. I. The model

Cited by 16 publications

References 4 publications

Numerical investigation of a fast-axial-flow CW CO2 laser

Numerical investigation of a fast-axial-flow CW CO2 laser

Kinetic modeling and optimum design of the discharge tube for the CO<sub>2</sub> laser with computational fluid dynamics method

Vibrational kinetics of the active media of CW CO2 lasers

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Numerical modelling of fast-flow CO2lasers. I. The model

Cited by 16 publications

References 4 publications

Numerical investigation of a fast-axial-flow CW CO2 laser

Numerical investigation of a fast-axial-flow CW CO2 laser

Kinetic modeling and optimum design of the discharge tube for the CO<sub>2</sub> laser with computational fluid dynamics method

Vibrational kinetics of the active media of CW CO2 lasers

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Numerical modelling of fast-flow CO₂lasers. I. The model