Flow field and flame surface density of turbulent flames by simultaneous PIV/OH-PLIF measurements

Yamamoto, Kazuhiro; Yamamori, Kenta; Asada, Yasuo

doi:10.1299/jtst.2018jtst0009

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…To see the appearance of the flame in the C-J combustor, photographs of flames are shown in Fig. 2 (Yamamoto et al, 2018). As seen in this figure, it is found that the flame length is longer for higher U m .…”

Section: Cyclone-jet Combustormentioning

confidence: 81%

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Flow field and local burning velocity affected by stretch in swirl flow of turbulent premixed flames

Yamamoto

Yamamori

Suzuki

2022

JTST

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In this study, we have investigated turbulent premixed flames affected by local stretch in a swirl flow, measured by the simultaneous OH-PLIF/SPIV system. Evaluating the transient of burning velocity and stretch rate, the flow and the flame dynamics in a cyclone-jet combustor were discussed. The flame front was determined by the OH fluorescence signal. Results show that the axial mean velocity becomes the maximum around the center axis, whereas the axial or the radial rms velocity takes the maximum at the position far from the center axis. These could be caused by the velocity fluctuation due to the flame and flow interactions. According to the local burning velocity and the stretch rate, the estimated Markstein number (Ma) roughly matches the value of the laminar flame. With an increase of the swirl number (S w ), the rms velocity is enlarged. Interestingly, the probability of higher burning velocity increases at larger S w . At the same time, the flame extinction occurs more frequently. Thus, it is derived that the swirl flow has a positive effect to increase the local burning velocity, but it simultaneously has a negative effect which causes the local flame extinction.

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Section: Cyclone-jet Combustormentioning

confidence: 81%

“…Propane and air were completely mixed and fed before flowing the mixture into the main nozzle and the cyclone nozzles. (Yamamoto et al, 2018).…”

Section: Cyclone-jet Combustormentioning

confidence: 99%

Flow field and local burning velocity affected by stretch in swirl flow of turbulent premixed flames

Yamamoto

Yamamori

Suzuki

2022

JTST

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“…Here, the variation of the chemiluminescence intensity along the height from the burner outlet was investigated. It should be noted that, different from the OH fluorescence signal by PLIF system (Yamamoto et al, 2007(Yamamoto et al, , 2009(Yamamoto et al, , 2018Tanahashi et al, 2008), the chemiluminescence intensity is the integrated value along the optical path. Therefore, if the flame has a conical shape, the signal depends on the flame diameter.…”

Section: Oh Chemiluminescence Intensity 321 Image Of Oh Chemiluminescence Intensitymentioning

confidence: 97%

OH chemiluminescence of methane-hydrogen premixed flames

Moriyama

Kimura

Asai

et al. 2021

JTST

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In this study, OH chemiluminescence of methane-hydrogen premixed flames formed on a Bunsen burner was investigated. As for the chemiluminescence intensity, we obtained the values at the edge of the flame and at the central axis of the flame, compared with the value calculated by the inverse Abel transform. It was found that the value at the central axis of the flame was less dependent on the measurement position than that at the edge of the flame, because the effect of integrated chemiluminescence intensity on the optical path was small. In addition, four filters with different center wavelengths were tested. Although the chemiluminescence intensity was changed by the filter, the dependence of the chemiluminescence intensity on the equivalence ratio was almost the same. For more discussion, the OH concentration and the heat release rate predicted by the numerical simulation of a one-dimensional methane-hydrogen flame were compared with the OH chemiluminescence and the burning velocity in experiments. It was revealed that, even when hydrogen was added by keeping the total equivalence ratio constant, the OH chemiluminescence intensity was proportional to the production rate of excited OH* produced by the reaction of CH and O2 concentrations. Similarly, the OH chemiluminescence intensity was apparently related with the heat release rate.

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“…As described, laser diagnostics including PLIF method are usually used to visualize the combustion field. So far, we have studied the combustion field when methane and hydrogen are used as fuels by the OH-PLIF method (Yamamoto et al, 2009(Yamamoto et al, , 2011(Yamamoto et al, , 2018. Normally, a very high-power laser is needed in PLIF measurements, combined with an expensive CCD camera with the image intensifier that amplifies the signal.…”

Section: Chemiluminescence Intensity and Digital Camera Signalsmentioning

confidence: 99%

“…For further study, it is necessary to study the CH and C2 chemiluminescence intensities of the mixed fuel of city gas and hydrogen, since CH and C2 chemiluminescence are in the range of visible light. In the case of the laser-induced fluorescence (PLIF) method which combines a high-power laser and a camera that captures weak signals, it is possible to adopt it for the direct combustion diagnosis, but it is an inexpensive system (Yamamoto et al, 2009(Yamamoto et al, , 2011(Yamamoto et al, , 2018. It is better to use a commercially available digital camera which can be used for visible light measurement.…”

Section: Introductionmentioning

confidence: 99%

Measurements of C2 and CH chemiluminescence of CH4/H2 flames by a digital camera

YAMAMOTO,

SAWADA

2024

JTST

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Since hydrogen does not emit carbon dioxide when it is burned, burning hydrogen directly is one option. However, as the hydrogen ratio in the total fuel increases, the visible flame emission becomes weaker. Therefore, when using fuels with hydrogen mixed with city gas, it is necessary to have a system that monitors incomplete combustion to ensure safe use of combustion equipment. In this study, we measured the C2 and CH chemiluminescence intensities of a laminar premixed flame of hydrogen and methane. These chemiluminescence intensities were evaluated using the ICCD camera, compared with flame images taken by the commercially available digital camera. Especially, we proposed a method to determine the C2 and CH chemiluminescence intensities simultaneously in terms of the signals composed of three primary colors of red (R), green (G), and blue (B) obtained by the digital camera images. The G signal of the flame obtained by the digital camera is almost proportional to the C2 chemiluminescence intensity. The B signal also shows a good linear relationship when data are divided into two groups according to the presence or the absence of the outer flame. We concluded that if the C2 and CH chemiluminescence intensities are predicted from the G signal and the B signal.

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Flow field and flame surface density of turbulent flames by simultaneous PIV/OH-PLIF measurements

Cited by 5 publications

References 8 publications

Flow field and local burning velocity affected by stretch in swirl flow of turbulent premixed flames

Flow field and local burning velocity affected by stretch in swirl flow of turbulent premixed flames

OH chemiluminescence of methane-hydrogen premixed flames

Measurements of C<sub>2</sub> and CH chemiluminescence of CH<sub>4</sub>/H<sub>2</sub> flames by a digital camera

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