Use of schlieren methods to study gas flow in laser technology

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081731%3A_____%2F16%3A00465803" target="_blank" >RIV/68081731:_____/16:00465803 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1117/12.2257212" target="_blank" >http://dx.doi.org/10.1117/12.2257212</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1117/12.2257212" target="_blank" >10.1117/12.2257212</a>

Result language

angličtina

Original language name

Use of schlieren methods to study gas flow in laser technology

Original language description

Laser technologies such as welding and cutting rely on process gases. We suggest to use schlieren imaging to visualize the gas flow during these processes. During the process of laser welding, the shielding gas flows to the welded area to prevent oxidation of the weld pool by surrounding air. The gas also interacts with hot plasma spurting from the key hole induced by the laser beam incident on the molten material. This interaction is quite complicated because hot plasma mixes with the cold shielding gas while the system is moving along the weld. Three shielding gases were used in the presented experiment: Ar, He and N2. Differences in dynamics of the flow are clearly visible on schlieren images. Moreover, high speed recording reveals a structure consisting of hot gas bubbles. We were also able to determine the velocity of the bubbles from the recording. During laser cutting, the process gas flows coaxially with the laser beam from the nozzle to remove the molten material out of the kerf. The gas flow is critical for the quality of the resulting edge of the cut. Schlieren method was used to study gas flow under the nozzle and then under the material being cut. This actually creates another slot nozzle. Due to the very low speed of flow below the material the schleiren method is already at the limit of its sensitivity. Therefore, it is necessary to apply a differential technique to increase the contrast. Distinctive widening of the flow shaped by the kerf was observed.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

BH - Optics, masers and lasers

OECD FORD branch

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Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Optics and Measurement International Conference 2016 (Proceedings of SPIE 10151)

ISBN

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ISSN

0277-786X

e-ISSN

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Number of pages

7

Pages from-to

"101510I:1"-"7"

Publisher name

SPIE

Place of publication

Bellingham

Event location

Liberec

Event date

Sep 11, 2016

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

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