New flame diagnostics scheme applicable to an ultra-lean combustion, so called "acetone-OH simultaneous PLIF", is presented. By using this scheme, a flame zone is indirectly imaged as the one between unburned and burned zones. Unburned zone is imaged by small amount of acetone seeded into fuel flow (less than 5% of fuel flow rate), whereas the burned zone is imaged by OH generated by combustion. Planar Laser-induced Fluorescence (PLIF) is applied for the 2-D imaging purpose. The combined excitation lines of 266nm and 283nm could pump up acetone as well as OH simultaneously and their fluorescence signals are properly collected by ICCD camera through the dual-peak band-pass filter, which is specially designed to pass efficiently OH and acetone fluorescence signals. Merit and demerit of the present scheme are both pointed in the body and an imaging capability of ultra-lean flame, whose equivalence ratio is less than 0.6, is presented under the demerit-minimized conditions.

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A novel technique consists of the following two conventional technique is presented in this article.; (1) multi-directional simultaneous photography and (2) 3D-CT(Computed Tomography). First, examples of the multi-directional simultaneous photography are given for entertainment use and research field. Next 3D-CT method is explained. Experimental results of the combined technique of 3D-CT with Guinness world record winning 158-lens-camera and 3D-PTV are shown. Time-series 3D-CT measurement, that is, 4D-CT accomplished with a single-high-speed camera and multi-mirror system is also introduced.

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Detailed understanding of turbulent combustion phenomena is very important to develop high efficiency combustors which contribute to resolve global environmental issues. Since turbulent combustion involves strong interactions between turbulence and combustion reactions, highly-sophisticated measurement techniques both for fluid motion and flames are required. For fluid velocity, state-in-art dual-plane stereoscopic particle image velocimetry (PIV) is shown and its importance in turbulent combustion researches is discussed. For flame measurements, advanced planar laser induced fluorescence (PLIF) techniques such as simultaneous CH-OH PLIF, double-pulsed CH PLIF and simultaneous dual-plane CH/single-plane OH PLIF are presented and investigations on local flame structure, global/local flame dynamics and three-dimensional flame structures are surveyed. Finally, current state and challenges of multi-dimensional/multi-variables laser diagnostics which consist of the advanced PLIF and color-based dual-plane stereoscopic PIV are presented.

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