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Spectroscopic Imaging of Combustion and Flames for Energy Systems
( Kuniyuki Kitagawa ) 경남대학교 신소재연구소 2013 신소재연구 Vol.25 No.-
From a viewpoint of green energy, visualization of physical properties that can not be seen by our eyes, by spectroscopic imaging, is a key to optimizing energy systems which utilize combustion and flames. Among the physical properties involved in combustion and flames, spatial distributions of temperature and chemical species are the most important physical properties. In this paper, the author will review several results of visualization by spectroscopic imaging as well as some basic principles involved in these applications. For example, you usually think that temperature is temperature, and no other properties. Do you know, however, what the definition of temperature is? Have you ever imagined that there are several sorts of temperatures, and that sometime they are not identical in magnitude? What is the reality of flame. Have you ever seen what chemical species are inside flames? In addition to combustion flames, spectroscopic imaging has been applied to discharge plasmas at temperatures over 4000 K. Do you know how to measure such high temperatures? Thermo couples that is employed at temperatures of up to 3000 K, can not be applied to measure plasma temperatures. It is a wonderful thing if we can visualize unseen properties, isn`t it?
Spectroscopic Examination and Analysis of Unconfined Swirling Flames
Ashwani Gupta,Sean Archer,Kuniyuki Kitagawa 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.1
Spectroscopic techniques have been used to examine the dynamic behavior of unconfined swirling flows and flames under fuel-lean combustion conditions. Specific spectroscopic diagnostics used include 3-D stereo particle image velocimetry (PIV) for the flow field, optical emission spectroscopy for CH, OH and C2 chemiluminescence, and infrared thermometry for the temperature. The effect of the radial distribution of the combustion air swirl is examined under burning and non-burning conditions in an experimental double concentric swirl burner that simulates one swirl cup of a practical gas turbine combustor using propane as the fuel. Results show the roles of the co- and the counter-swirl distributions in a burner on the flow structure, both with and without combustion. Both the swirl distribution and combustion significantly influence the flow field, as well as the spatial distributions of CH, OH, C2, and the thermal field in flames. Combustion causes a significant increase in the velocity magnitudes and in the entrained mass flow rate for the co-swirl distribution.0
Ceramic Nano-particles for Better microstructure of Thin Film: Pb(Zr0.58 TiO0.42)O3
( Jun Byung Sei ),( Kuniyuki Kitagawa ) 경남대학교 신소재연구소 2012 신소재연구 Vol.24 No.-
Many efforts to develop ceramic products for high technology systems have concentrated on obtaining green state microstructures with uniformly packed, equiaxed, narrow size distribution powders and pores of inter-particles. The ultrasonic spray combustion synthesis method is employed, in this study, to synthesize ultrafine PZT(x=0.52 to 0.55) powders, To initiate exothermic combustion of the droplets, metal nitrates is used as an oxidizer and carbohydrazide is used as fuel source. The flow rate is controlled by use of O2 carrier gas. And also a filter media is used to avoid the coagulation of droplets. Electrophoretic deposition(EPD) method is employed to get a uniform green microstructure of Pb(Zr0.58 TiO0.42)O3 film highly homogeneous cast with a high mechanical strength and a low surface roughness if a well dispersed suspension is used. Moreover the EPD method is also well known due to the low equipment cost, high deposition rate, and easily controlled layer thickness, allowing for an even, dense, and large deposition layer. Viscous sintering methods is introduced to avoid a shrink during sintering process. This shrinkage may cause a stress between film and substrate.
( Yoko Nunome ),( Hyun Kook Park ),( Kenji Kodama ),( Yasuaki Ueki ),( Ryo Yoshiie ),( Sang Chun Lee ),( Kuniyuki Kitagawa ),( Ichiro Naruse ) 경남대학교 신소재연구소 2013 신소재연구 Vol.25 No.-
Toxic volatile organic compounds (VOCs) have serious implications for the environment and human health. An analytical method for the rapid, direct detection of VOCs without any sample pretreatment was successfully developed by combining soft plasma ionization (SPI) with time-of-flight mass spectrometry (TOFMS). The SPI source, based on Ref. 1 and re-designed for this work, is shown schematically in Fig. 1. Vapor from a liquid sample was diluted to a ratio selected in accordance with the amount of ambient air. To achieve softer ionization of VOCs by the SPI method, discharge parameters (current and pressure) were varied to determine the optimal experimental conditions. Use of ambient air as the discharge gas was the aim for practical in situ analysis. Optimal conditions for the SPI source were determined to be: sample dilution ratio, R = 0.30; discharge current, 50 mA; and ambient air pressure, 1000 Pa. All mass spectra of the the organic solvents exhibited molecular ion base peaks, which demonstrated the achievement of soft ionization by the SPI method. From these results, an ionization mechanism in the SPI-TOFMS system was suggested in which excitation of N2 would facilitate the ionization of sample molecules. It is noteworthy that the SPI-TOFMS system enabled highly soft ionization by using practical ambient air as the discharge gas rather than cylinder gas. Therefore, this SPI-TOFMS system was validated and was well suited for the in situ on-line monitoring of VOCs. Further work will be necessary to evaluate quantification methods for the accuracy and reproducibility of our measurements.