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An assessment of high-power light-emitting diodes for high frame rate schlieren imaging

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Abstract

The feasibility of using high-power light-emitting diodes (LED) as a light source for high frame rate schlieren imaging is investigated. Continuous sequences of high-intensity light pulses are achieved by overdriving the LED with current pulses up to a factor of ten beyond its specifications. In comparison to commonly used pulsed light sources such as gas discharge lamps and pulsed lasers, the pulsed LED has several attractive advantages: the pulse-to-pulse intensity variation is on the same order of magnitude as the detector (camera) noise permitting quantitative intensity measurements. The LED’s narrow emission bandwidth reduces chromatic abberations, yet it is spectrally wide enough to prevent the appearance of speckle and diffraction effects in the images. Most importantly, the essentially lag-free light emission within tens of nanoseconds of the applied current pulse allows the LED to be operated at varying frequencies (i.e., asynchronously), which generally is not possible with neither lasers nor discharge lamps. The pulsed LED source, driven by a simple driver circuit, is demonstrated on two schlieren imaging setups. The first configuration visualizes the temporal evolution of shock structures and sound waves of an under-expanded jet that is impinging on a rigid surface at frame rates of 500 kHz to 1 MHz. In a second application, long sequences of several thousand high-resolution images are acquired on a free jet at a frame rate of 1 kHz. The low-intensity fluctuation and large sample number allow a reliable computation of two-point correlation data from the image sequences.

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References

  • Bretthauer B, Meier GEA, Stasicki B (1991) An electronic Cranz–Schardin camera. Rev Sci Instrum 62(7):364–368. doi:10.1063/1.1142129

    Article  Google Scholar 

  • Buttsworth DR, Sercombe DBT (2008) Cranz–Schardin visualisation of a hypersonic cone with gas injection. In: 28th International congress on high-speed imaging and photonics, SPIE vol 7126. University of New South Wales at ADFA, Canberra. doi:10.1117/12.822032

  • Deblock Y, Ducloux O, Derbesse L, Merlen A, Pernod P (2007) High speed single charge coupled device Cranz–Schardin camera. Rev Sci Instrum 78(3):035,111–1–035,111–4. doi:10.1063/1.2714771

    Google Scholar 

  • Etoh TG, Poggemann D, Ruckelshausen A, Theuwissen A, Kreider G, Folkerts HO, Mutoh H, Kondo Y, Maruno H, Takubo K, Soya H, Takehara K, Okinaka T, Takano Y, Reisinger T, Lohmann C (2002) A ccd image sensor of 1 mframes/s for continuous image capturing of 103 frames. In: IEEE International solid-state circuits conference, 2002, digest of technical papers. ISSCC, vol 1, pp 46–443. San Francisco, CA, USA. doi:10.1109/ISSCC.2002.992931

  • Henderson B (2003) The connection between sound production and jet structure of the supersonic impinging jet. J Acoust Soc Am 111(n2):735–774. doi:10.1121/1.1436069

    Article  Google Scholar 

  • Henderson B, Bridges J, Wernet M (2005) An experimental study of the oscillatory flow structure of tone-producing supersonic impinging jets. J Fluid Mech 542:115–137. doi:10.1017/S0022112005006385

    Article  MATH  Google Scholar 

  • Hiller W, Lent HM, Meier GEA, Stasicki B (1987) A pulsed light generator for high speed photography. Exp Fluids 5(2):141–144. doi:10.1007/BF00776185

  • Klinner J, Willert C (2011) On the implementation of tomographic shadowgraphy for spray diagnostics. In: 9th International symposium of particle image velocimetry (PIV’11). Kobe University, Kobe, Japan

  • Luminus Devices, Inc (2008) Technical product data sheet PDS-001226: CBT-120 series, PhlatLight LED Illumination products

  • Risborg A, Mitchell D, Honnery D, Soria J (2008) Instabilities in underexpanded impinging jets. In: Fifth Australian conference on laser diagnostics in fluid mechanics and combustion. The University of Western Australia

  • Risborg A, Soria J (2008) High-speed optical measurements of an underexpanded supersonic jet impinging on an inclined plate. In: 28th International congress on high-speed imaging and photonics, SPIE vol 7126. UNSW at ADFA, Canberra. doi:10.1117/12.822137

  • Settles GS (2001) Schlieren and shadowgraph techniques. Springer, Berlin

    Book  MATH  Google Scholar 

  • Stasicki B, Hiller W, Meier GEA (1984) Hochfrequenz-Stroboskop mit LED-Lichtquelle. Tech Messen 51:217–220

    Google Scholar 

  • Stasicki B, Hiller W, Meier GEA (1990) Light pulse generator for high speed photography using semiconductor devices as a light source. Opt Eng 29(7):821–827. doi:10.1117/12.55647

    Article  Google Scholar 

  • Stasicki B, Kompenhans J, Willert C (2010) Pulsed high-power LED illuminator for the visualisation and measurement of flows. In: ISFV14—14th International symposium on flow visualization, ISFV14-3E-6 206, pp 1–8. http://elib.dlr.de/62801/

  • Umeda Y, Ishii R (2002) Existence of mach cones and helical vortical structures around the underexpanded circular jet in the helical oscillation mode. J Acoust Soc Am 112:99–107. doi:10.1121/1.1487839

    Article  Google Scholar 

  • Willert C, Freitag S, Hassa C (2008) High speed imaging of fuel sprays using a low-cost illumination source. In: 22nd European conference on liquid atomization and spray systems (ILASS 2008). http://elib-v3.dlr.de/55164/

  • Willert C, Mitchell D, Soria J (2010) Megahertz schlieren imaging of shock structure and sound waves in under-expanded, impinging jets. arXiv physics.flu-dyn. http://arxiv.org/abs/1010.3186v1

  • Willert C, Moessner S, Freitag S, Hassa C (2010) High speed shadowgraphy of a combusting air blast atomizer spray at elevated pressure. In: 23rd Annual conference on liquid atomization and sprays, ILASS Europe 2010. http://elib.dlr.de/65220/

  • Willert C, Stasicki B, Klinner J, Moessner S (2010) Pulsed operation of high-power light emitting diodes for imaging flow velocimetry. Meas Sci Technol 21(7):075,402. http://stacks.iop.org/0957-0233/21/i=7/a=075402

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Acknowledgments

The financial support of this research by the Australian Research Council is gratefully acknowledged.

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Correspondence to Christian E. Willert.

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Willert, C.E., Mitchell, D.M. & Soria, J. An assessment of high-power light-emitting diodes for high frame rate schlieren imaging. Exp Fluids 53, 413–421 (2012). https://doi.org/10.1007/s00348-012-1297-1

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  • DOI: https://doi.org/10.1007/s00348-012-1297-1

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