Melt removal mechanism by transverse gas flow during laser irradiation

Wei, Chenghua; Zhu, Yongxiang; Zhou, Menglian; Ma, Zhiliang; Wu, Taotao

doi:10.1117/12.2267060

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…The air flow can lead to faster removal of molten material, but it can also lead to sufficient cooling of the specimen, which prolongs the perforation 11,12,19,21 . Melt pool dynamics can strongly depend on experimental conditions such as air flow velocity and direction of gravity 9,21,22 . Furthermore, a varying laser penetration is reported for nitrogen or normal air 9,23 .…”

Section: Introductionmentioning

confidence: 99%

Change of dominant material properties in laserperforation process with high-energy lasers up to 120kilowatt

Reich,

Goesmann,

Heunoske

et al. 2023

Preprint

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In laser materials processing, energy losses due to reflection, heat conduction and thermal radiation play an important role. In this publication, we show that with increasing laser intensity, the energy lost within the sample becomes less important for metal perforation processes. We compare the laser-matter interaction of aluminium and steel plates. Material parameters such as density, melting point and especially thermal conductivity differ strongly, leading to much longer perforation times for aluminium in comparison to steel at laser powers of 20 kW. However, this behaviour changes at laser powers of more than 80 kW where the perforation times of aluminium become shorter than the corresponding times for steel. By comparing experimental data and simulations, we conclude that thermal conduction is the dominant factor of energy loss at low powers, but is reduced at high laser powers.

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Section: Introductionmentioning

confidence: 99%

Change of dominant material properties in laserperforation process with high-energy lasers up to 120kilowatt

Reich,

Goesmann,

Heunoske

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Moreover, oxidation processes of the metal surface were observed to have a major influence on the absorptance of the laser. Baek et al and Wei et al irradiated metal samples with a 1.07 µm cw laser and studied the melt-through characteristics in flow speeds up to 90 m/s [7] [8]. In addition to a reduced perforation time by the gas flow, Baek et al determined threshold irradiances in dependence of material thickness and beam absorptivity.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of high-power laser irradiation of missile materials in subsonic and supersonic flows

Schäffer

Allofs²,

Gruhn³

et al. 2022

High-Power Lasers and Technologies for Optical Countermeasures

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The technology of missiles and of their countermeasures is evolving continuously. High-power lasers are an option to encounter these threats. In order to understand their potential in such a scenario, it is vital to investigate the laser effects in the presence of a corresponding aerodynamic environment. Thus, experimental and numerical investigations were conducted cooperatively by Fraunhofer Ernst-Mach-Institut and the Supersonic and Hypersonic Technologies Department of DLR. An ytterbium fiber laser system was installed at the supersonic wind tunnel VMK. The laboratory was fit to meet necessary laser safety requirements. Combined subsonic and supersonic flow and high-power laser experiments with flow velocities up to a Mach number of 3 and a laser power up to 10 kW were realized. Two kind of tests were performed, focusing on laser beam distortion through aero-optical effects and on high-power laser effects, respectively. The interaction effects between aerodynamics, laser radiation and irradiated targets were studied on flatplates as well as cylindrical and radome targets, simulating generic missile design. Irradiated objects consisted of steel, aluminum, carbon-fiber-reinforced polymer and the ceramic-based composite WHIPOX. While beam distortions were studied with a wavefront sensor, damaging processes were investigated by measuring the perforation time of the targets, as well as via high-speed imaging, thermography as well as Schlieren imaging. Numerical three-dimensional, steady, and uncoupled simulations were performed. The data indicated complex interactions between material, laser beam, and aerodynamics. This investigation can be used as an initial basis for further analysis of laser-material-aerodynamic interactions with respect to missile defense.

show abstract

Change of dominant material properties in laser perforation process with high-energy lasers up to 120 kilowatt

Reich,

Goesmann,

Heunoske

et al. 2023

Sci Rep

View full text Add to dashboard Cite

In laser materials processing, energy losses due to reflection, heat conduction and thermal radiation play an important role. In this publication, we show that with increasing laser intensity, the energy lost within the sample becomes less important for metal perforation processes. We compare the laser-matter interaction of aluminum and steel plates. Material parameters such as density, melting point and especially thermal conductivity differ strongly, leading to much longer perforation times for aluminum in comparison to steel at laser powers of 20 kW. However, this behavior changes at laser powers of more than 80 kW where the perforation times of aluminum become shorter than the corresponding times for steel. By comparing experimental data and simulations, we conclude that thermal conduction is the dominant factor of energy loss at low powers, but is reduced at high laser powers.

show abstract

Melt removal mechanism by transverse gas flow during laser irradiation

Cited by 4 publications

References 8 publications

Change of dominant material properties in laserperforation process with high-energy lasers up to 120kilowatt

Change of dominant material properties in laserperforation process with high-energy lasers up to 120kilowatt

Experimental investigation of high-power laser irradiation of missile materials in subsonic and supersonic flows

Change of dominant material properties in laser perforation process with high-energy lasers up to 120 kilowatt

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