Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer
Multipulse laser processing of materials is promising because of the additional possibilities to control the thickness of the treated and the heat-affected zones and the energy efficiency. To study the physics of mutual interaction of pulses at high repetition rate, a model is proposed where heat tr...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-11-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/9/22/4785 |
| _version_ | 1818822096331997184 |
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| author | Andrey V. Gusarov Oleg B. Kovalev |
| author_facet | Andrey V. Gusarov Oleg B. Kovalev |
| author_sort | Andrey V. Gusarov |
| collection | DOAJ |
| description | Multipulse laser processing of materials is promising because of the additional possibilities to control the thickness of the treated and the heat-affected zones and the energy efficiency. To study the physics of mutual interaction of pulses at high repetition rate, a model is proposed where heat transfer in the target and gas-dynamics of vapor and ambient gas are coupled by the gas-dynamic boundary conditions of evaporation/condensation. Numerical calculations are accomplished for a substrate of an austenitic steel subjected to a 300 ns single pulse of CO<sub>2</sub> laser and a sequence of the similar pulses with lower intensity and 10 μs inter-pulse separation assuring approximately the same thermal impact on the target. It is revealed that the pulses of the sequence interact due to heat accumulation in the target but they cannot interact through the gas phase. Evaporation is considerably more intensive at the single-pulse processing. The vapor is slightly ionized and absorbs the infrared laser radiation by inverse bremsstrahlung. The estimated absorption coefficient and the optical thickness of the vapor domain are considerably greater for the single-pulse regime. The absorption initiates optical breakdown and the ignition of plasma shielding the target from laser radiation. The multipulse laser processing can be applied to avoid plasma ignition. |
| first_indexed | 2024-12-18T23:18:39Z |
| format | Article |
| id | doaj.art-5472cc9038b9473fbe1e562b4c86231d |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-12-18T23:18:39Z |
| publishDate | 2019-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-5472cc9038b9473fbe1e562b4c86231d2022-12-21T20:48:04ZengMDPI AGApplied Sciences2076-34172019-11-01922478510.3390/app9224785app9224785Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat TransferAndrey V. Gusarov0Oleg B. Kovalev1Moscow State University of Technology STANKIN, Vadkovsky Per. 3a, 127055 Moscow, RussiaKhristianovich Institute of Theoretical and Applied Mechanics SB RAS, Institutskaya Str. 4/1, 630090 Novosibirsk, RussiaMultipulse laser processing of materials is promising because of the additional possibilities to control the thickness of the treated and the heat-affected zones and the energy efficiency. To study the physics of mutual interaction of pulses at high repetition rate, a model is proposed where heat transfer in the target and gas-dynamics of vapor and ambient gas are coupled by the gas-dynamic boundary conditions of evaporation/condensation. Numerical calculations are accomplished for a substrate of an austenitic steel subjected to a 300 ns single pulse of CO<sub>2</sub> laser and a sequence of the similar pulses with lower intensity and 10 μs inter-pulse separation assuring approximately the same thermal impact on the target. It is revealed that the pulses of the sequence interact due to heat accumulation in the target but they cannot interact through the gas phase. Evaporation is considerably more intensive at the single-pulse processing. The vapor is slightly ionized and absorbs the infrared laser radiation by inverse bremsstrahlung. The estimated absorption coefficient and the optical thickness of the vapor domain are considerably greater for the single-pulse regime. The absorption initiates optical breakdown and the ignition of plasma shielding the target from laser radiation. The multipulse laser processing can be applied to avoid plasma ignition.https://www.mdpi.com/2076-3417/9/22/4785multipulse laser processingheat transfergas dynamicslaser evaporationlaser plasma |
| spellingShingle | Andrey V. Gusarov Oleg B. Kovalev Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer Applied Sciences multipulse laser processing heat transfer gas dynamics laser evaporation laser plasma |
| title | Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer |
| title_full | Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer |
| title_fullStr | Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer |
| title_full_unstemmed | Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer |
| title_short | Sequences of Sub-Microsecond Laser Pulses for Material Processing: Modeling of Coupled Gas Dynamics and Heat Transfer |
| title_sort | sequences of sub microsecond laser pulses for material processing modeling of coupled gas dynamics and heat transfer |
| topic | multipulse laser processing heat transfer gas dynamics laser evaporation laser plasma |
| url | https://www.mdpi.com/2076-3417/9/22/4785 |
| work_keys_str_mv | AT andreyvgusarov sequencesofsubmicrosecondlaserpulsesformaterialprocessingmodelingofcoupledgasdynamicsandheattransfer AT olegbkovalev sequencesofsubmicrosecondlaserpulsesformaterialprocessingmodelingofcoupledgasdynamicsandheattransfer |