An experimental study on detailed flame structure of liquid fuel sprays with and without gaseous fuel

Nakabe, Kazuyoshi; Mizutani, Yukio; Hirao, T.; Fujioka, Hiroyuki

doi:10.1016/0010-2180(91)90034-9

Cited by 18 publications

(5 citation statements)

References 16 publications

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“…The premixed spray is droplet-laden two-phase flow with minimal slip velocity between air and droplets. This was introduced into a combustion study by Mizutani and Nishimoto (Mizutani, Y. and Nishimoto, 1972), and studies on the detailed structure of the spray flame were performed by Nakabe et al (Nakabe et al, 1988, Nakabe et al, 1991.…”

Section: Premixed Spray Flame Burnermentioning

confidence: 99%

Optical measurement and numerical simulation of spray combustion

Akamatsu

2016

JTST

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To elucidate the detailed combustion mechanism of spray flames, experimental and numerical studies were conducted. In the experiment, simultaneous time-series measurements of OH chemiluminescence, CH-band emission, and Mie scattering from droplets by using a Cassegrain optics, spray image illuminated by laser light sheet, the droplet diameter and velocity measured by using PDA were applied to a premixed spray flame of kerosene. In addition, numerical calculations were conducted on combustion processes of n-decane spray entering gaseous flat-flame stabilized in laminar counter flow configuration. With these experimental and numerical results, time evolution of burning processes of fuel spray was discussed in detail. impossible to measure all physical quantity in spray flame by only experiments. In this review, an outline about research contents conducting in our laboratory are presented to observe detailed structure of the spray combustion by compound optical measurements and to perform detailed numerical simulation by modeling the phenomena. Observation of detailed structure of the spray combustion by compound optical measurementsAs mentioned earlier, the behaviour not as a single droplet but as a group or cluster is the key factor in actual spray flames. Theoretically analyzing the combustion of a quasi-steady isolated spherical droplet cluster of diameter, D C

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Section: Premixed Spray Flame Burnermentioning

confidence: 99%

Optical measurement and numerical simulation of spray combustion

Akamatsu

2016

JTST

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“…This results in inhomogeneous distribution of spray droplets (regions where droplet concentration is very high above the mean value as well as regions devoid of droplets) leading to spatial and temporal fluctuations in local droplet number density within sprays. Droplet clustering have been identified in several experiments on non-reacting and reacting sprays ( [7,8,9,10,11,12]). However, the role of droplet clustering on local spray unsteadiness and droplet group evaporation/combustion are not yet well explored.…”

Section: Introductionmentioning

confidence: 99%

Two-Phase Characterization for Turbulent Dispersion of Sprays: A Review of Optical Techniques

Sahu

Manish

Hardalupas

2017

Energy, Environment, and Sustainability

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In liquid fueled combustion the interaction of spray droplets with surrounding turbulent air flow is crucial since it influences the evaporation rate of the fuel droplets and the process of air and fuel vapor mixture preparation. For detail understanding on the droplet-turbulence interaction mechanisms as well as to validate numerical simulations of sprays, simultaneous measurement of both dispersed and carrier phases of the spray is essential. This way the vortical interaction of droplets can be fully characterized such that important issues such as local spray unsteadiness and spatio-temporal inhomogeneity of droplet concentration due to droplet clustering, and group evaporation of droplets can be addressed. This review focuses on the advances in the optical diagnostics (especially the planar techniques) in the last few decades to meet these requirements. Due to broad size and velocity distributions of spray droplets, the application of the two-phase measurement techniques to sprays encounters challenges especially in phase discrimination. Additionally, for sprays, it is not sufficient to simultaneously measure two-phase velocities but the droplet size is also important since the dynamic drag on droplets is according to their size and velocity relative to the surrounding gas flow. The techniques with such capability are explored. The sources of uncertainty, and advantages and limitations of different two-phase measurement approaches are analyzed according to their application to dense and dilute sprays.

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“…Compared with laser diagnostics, 3D-CTC is substantially simpler and easier to implement, also can provide information about key combustion quantities (e.g., heat release rate, local equivalence ratio) [4] , making it attractive for applications in harsh industrial environments. Chemiluminescence of flame have been studied for more than one century, and the first approach of measurement by designing a collection system to detect relatively small volume was demonstrated in 1991 [5] . Cassegrain telescope optics subsequently have been utilized for non-intrusive measurement [6,7] .…”

Section: Introductionmentioning

confidence: 99%

Computed tomography measurement of 3D combustion chemiluminescence using single camera

Wang¹,

Li²,

Zeng³

et al. 2016

Optical Measurement Technology and Instrumentation

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Instantaneous measurement of flame spatial structure has been long desired for complicated combustion condition (gas turbine, ramjet et.). Three dimensional computed tomography of chemiluminescence (3D-CTC) is a potential testing technology for its simplicity, low cost, high temporal and spatial resolution. In most former studies, multi-lens and multi-CCD are used to capture projects from different view angles. In order to improve adaptability, only one CCD was utilized to build 3D-CTC system combined with customized fiber-based endoscopes (FBEs). It makes this technique more economic and simple. Validate experiments were made using 10 small CH4 diffusion flame arranging in a ring structure. Based on one instantaneous image, computed tomography can be conducted using Algebraic Reconstruction Technique (ART) algorithm. The reconstructed results, including the flame number, ring shape of the flames, the inner and outer diameter of ring, all well match the physical structure. It indicates that 3D combustion chemiluminescence could be well reconstructed using single camera. Three dimensional computed tomography of chemiluminescence (3D-CTC), radicals, reconstruction, AlgebraicReconstruction Technique (ART) 1.IntroductionChemiluminescence of flame are the emitted photons caused by the transition of excited-states radicals to ground-states. It is recognized as an important indictor in combustion diagnostics and control [1][2][3] . Compared with laser diagnostics, 3D-CTC is substantially simpler and easier to implement, also can provide information about key combustion quantities (e.g., heat release rate, local equivalence ratio) [4] , making it attractive for applications in harsh industrial environments. Chemiluminescence of flame have been studied for more than one century, and the first approach of measurement by designing a collection system to detect relatively small volume was demonstrated in 1991 [5] . Cassegrain telescope optics subsequently have been utilized for non-intrusive measurement [6,7] . Multiple dimension measurement could be accomplished by rapid scanning the focusing plane if the target flame is steady. This method can not resolve the temporal dynamics of the combustion processes. The second approach for multiple dimension measurement is 3D-CTC technique combining chemiluminescence with tomography to obtain spatially-resolved measurements, which can provide more directly and critical structural information. Nonetheless, high spatial resolution and rapid temporal resolution measurement is a tremendous challenge for 3D-CTC technique due to the limits of optical access and hardware. In recent years, 3D-CTC have been widely studied due to the great improvements of capabilities of optical sensing and computing technologies. Based on different imaging system, 3D-CTC can be divided into three categories [3] . The first category obtains the image projection by custom-made lens and film [8] , the second method based on lens and CCD cameras [4,9,10] , and the third method combined fiber-based endosc...

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An experimental study on detailed flame structure of liquid fuel sprays with and without gaseous fuel

Cited by 18 publications

References 16 publications

Optical measurement and numerical simulation of spray combustion

Optical measurement and numerical simulation of spray combustion

Two-Phase Characterization for Turbulent Dispersion of Sprays: A Review of Optical Techniques

Computed tomography measurement of 3D combustion chemiluminescence using single camera

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