Abstract
The results of measurement of fluctuations of brightness temperature T in the region of exposure to laser radiation of a 3 mm-thick steel plate are presented. The local luminosity along the cut-front was measured using two-color multichannel pyrometer. Cutting trials were carried out with CO2 laser (10.6 μm, 1200 W) and fiber laser (1.07 μm, 1800 W). Special attention was given to the frequency range of temperature fluctuations above frequency of melt overflight, aiming on on-line monitoring applications. It is shown that local fluctuations of T are related to local melt’s surface deformations due to unequal radiation absorption; thus the noise spectrum of T fluctuations reflects turbulent surface deformation, caused by gas jet and capillary waves. It is also shown that the thermo-capillary effect with capillary-wave turbulence generation can be observed in case of exposure to 10.6 μm radiation with a laser intensity of about 1 MW/cm2. The power law of “−7/6” describes the spectrum of the T fluctuation variance in this case of anomalous absorption of radiation, and the standard deviation of T is in excess of 10 K for a frequency of 14 kHz. There is no such effect in case of fiber-laser radiation applying, and the source of the capillary waves is only forced low-frequency deformations of the melt surface. The standard deviation of T does not exceed 3 K on the frequency of 14 kHz, and above, and a power law of the spectrum fluctuation is described by about “−3” in that range.
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M. Hansmann, I. Decker, J. Ruge, in Power Beam Technology, Brighton, England (1986), pp. 440–445
I. Decker, H. Heyn, D. Martinen, H. Wohlfahrt, Proc. SPIE 3097, 29 (1997)
J.R. Duflou, E.F. Sichani, J. De Keuster, J.-P. Kruth, in ICALEO Proceedings, Orlando, USA, vol. 102 (2009), pp. 527–536
F. Bardin, S. Morgan, S. Williams, R. McBride, A.J. Moore, J.D.-C. Jones, D.P. Hand, Appl. Opt. 44, 6841 (2005)
J. De Keuster, J.R. Duflou, J.-P. Kruth, Int. J. Adv. Manuf. Technol. 35, 115 (2007)
P. Sforza, V. Santecesaria, Proc. SPIE 2207, 836 (1994)
P. Sforza, D. de Blasiis, V. Lombardo, Proc. SPIE 3097, 97 (1997)
T. Engel, M. Kane, J. Fontaine, Proc. SPIE 3097, 727 (1997)
I. Miyamoto, H. Maruo, Weld. World 29, 283 (1991)
R.V. Grishaev, V.D. Dubrov, N.G. Dubrovin, Y.N. Zavalov, J. Guangdong Non-Ferrous Met. 3, 635 (2005)
V.S. Golubev, A.V. Dubrov, Yu.N. Zavalov, V.D. Dubrov, in Theses of 5th International Conference on Advanced Optoelectronics and Lasers (CAOL’2010), Sevastopol, Ukraine, 10–14 Sept. (2010), pp. 182–184. IEEE CN: CFP10814-PRT
V.S. Golubev, R.V. Grishaev, V.D. Dubrov, N.G. Dubrovin, Yu.N. Zavalov, in Theses of XIId International Conference on Physical and Chemical Processes in Selection of Atoms and Molecula, Zvenigorod, Russia, 31 March–4 Apr 2008 (TsNIIAtomInform, Moscow, 2008), pp. 255–260. ISBN 978-5-89513-133-6, in Russian
V.S. Golubev, Proc. SPIE 2713, 219 (1995)
P.G. Frick, Turbulence: Method and Approach (Moscow, 2003), in Russian
V.E. Zakharov, V.S. L’vov, G. Falkovich, Kolmogorov Spectra of Turbulence I: Wave Turbulence, Springer Series in Nonlinear Dynamics (Springer, Berlin, 1992)
G.V. Kolmakov, A.A. Levchenko, M.Yu. Brazhnikov, L.P. Mezhov-Deglin, A.N. Silchenko, P.V.E. McClintock, Phys. Rev. Lett. 93, 074501 (2004)
E. Falcon, C. Laroche, Phys. Rev. Lett. 98, 094503 (2007)
M.Yu. Brazhnikov, A.A. Levchenko, L.P. Mezhov-Deglin, Instrum. Exp. Tech. 45, 758 (2002)
N.I. Koroteev, V.I. Emel’yanov, V.N. Seminogov, S.A. Akhmanov, Usp. Fiz. Nauk 28, 1084 (1985)
V.E. Zakharov, N.N. Filonenko, J. Appl. Mech. Tech. Phys. 5, 310 (1967)
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Dubrov, A.V., Dubrov, V.D., Zavalov, Y.N. et al. Application of optical pyrometry for on-line monitoring in laser-cutting technologies. Appl. Phys. B 105, 537–543 (2011). https://doi.org/10.1007/s00340-011-4611-3
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DOI: https://doi.org/10.1007/s00340-011-4611-3