Laser-induced vaporisation of metal as a Riemann problem

Aden, Mirko; Beyer, Eckhard; Herziger, G.

doi:10.1088/0022-3727/23/6/004

Cited by 56 publications

(31 citation statements)

References 3 publications

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“…Further investigation on the dependence of  R on T s is out of the scope of this work, it may be worthwhile to mention that the asymptotic convergence at high temperature depends more or less on geometry around the considered surface point. Aden et al [29,30] theoretically analysed metal vapour expansion dynamics in 3D geometry. It was shown that with the increase of the laser intensity and that of T s ,  R approaches ~ 0.2.…”

Section: Temperature Dependence Of Pmentioning

confidence: 99%

Experimental determination of temperature threshold for melt surface deformation during laser interaction on iron at atmospheric pressure

Hirano¹,

Fabbro²,

Muller³

2011

J. Phys. D: Appl. Phys.

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. . It is thus essential to estimate the recoil pressure in order to describe physical processes or to carry out numerical simulations. However, there exists no quantitative estimation of the recoil pressure near the boiling temperature (T v ), which is particularly important in welding process. In this study we experimentally investigated the recoil pressure of pure iron around T v . The main interest was to determine the threshold surface temperature to start deformation of melt surface. Using camera-based temperature measurement with accurate evaluation of emissivity from experiment, it was shown that the surface temperature has to reach T v to initiate the melt surface deformation. This result provides the first experimental evidence for the frequently used assumption that a deep keyhole welding requires surface temperature over T v . It is indicated also that, in normal gas-assisted laser cutting process, the recoil pressure hardly contributes to material ejection when the surface temperature is lower than T v , as opposed to commonly believed presumption.

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Section: Temperature Dependence Of Pmentioning

confidence: 99%

Experimental determination of temperature threshold for melt surface deformation during laser interaction on iron at atmospheric pressure

Hirano¹,

Fabbro²,

Muller³

2011

J. Phys. D: Appl. Phys.

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“…Experimental measurements of plume flow fields at conditions comparable to those used in this simulation are not available in the literature. In a prior simulation, Aden et al 6 solved the Euler equations, steady heat-flow equation, and the kinetic equation to calculate the gas dynamic properties at the edge of the Knudsen layer. They calculated the velocity of the metal vapor and the displaced ambient air for an absorbed laser intensity of 10 10 W m Ϫ2 .…”

Section: Numerical Modeling Study Resultsmentioning

confidence: 99%

CO 2 laser–plume interaction in materials processing

Kim

Farson

2001

Journal of Applied Physics

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In laser materials processing, localized evaporation caused by focused laser radiation forms a plume of mixed vapor and ambient gas above the material surface. The beam is refracted and absorbed as it traverses the plume, thus modifying its power density on the surface. In this work, plume–beam interaction is studied using an axisymmetric, high-temperature gas-dynamic model of a plume formed by vapor from an iron surface. The beam propagation in the plume is calculated from the paraxial wave equation including absorption and refraction. The simulation results quantify the effects of plasma plume properties on the beam radius and laser power density variations at the material surface. It is shown that absorption and refraction in the plume have significant impacts on the laser–material interaction. Absorption of the beam in the plume has much less direct effect on the power density at the material surface than refraction does. However, absorption is essential for the formation of the plume, without which there is no refraction. Helium gas is more efficient than argon for reducing the beam refraction and absorption effects. Laser energy reflected from the material surface has significant effects on the plume properties.

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“…He treated this layer as a gasdynamic discontinuity across which certain jump conditions expressing conservation mass, momentum, and energy. The laser-induced vaporization process of metal was also theoretically investigated by Aden et al [12], who calculated the gas dynamical properties of the edge of the Knudsen layer using the Euler equations, the stationary heat flow equation and the kinetic equations. On an assumption that a stationary limit of the vaporization process is reached, the solution of the Euler equations is equivalent to that of a Riemann problem.…”

Section: Laser-induced Ablationmentioning

confidence: 99%

Thermal and Mechanical Effects of Laser Irradiation on Targets

Chen

2001

Engineering Plasticity and Impact Dynamics

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The essence of laser beam is a directed high-intensity energy flow. Laser-material interaction features highly sophisticated microscopic mechanisms and a variety of macroscopic effects. This chapter discusses laser-induced macroscopic thermal and mechanical effects on targets from energy sediment with laser irradiance lying in the "material damage range" (10°W/cm 2 < I L < 10 13 W/cm 2 ). As laser power density decreases in this range, a large spectrum of macroscopic thermal and mechanical phenomena, such as impulse coupling, laser-induced shock wave and target spallation, melting and vaporization, thermal softening, thermal stress, prevail. These phenomena are closely related to intense shock or elasoplastic characteristics of materials and structures.

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Laser-induced vaporisation of metal as a Riemann problem

Cited by 56 publications

References 3 publications

Experimental determination of temperature threshold for melt surface deformation during laser interaction on iron at atmospheric pressure

Experimental determination of temperature threshold for melt surface deformation during laser interaction on iron at atmospheric pressure

CO 2 laser–plume interaction in materials processing

Thermal and Mechanical Effects of Laser Irradiation on Targets

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