• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.347-356
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• 2015

A study has been conducted numerically to investigate the lifted flat syngas flame structure of impinging jet flame configuration with the global strain rates in 10% hydrogen content. In this study, the effects of strain rate were major parameters on chemistry kinetics and flame structure at stagnation point. The numerical results were calculated by SPIN application of the CHEMKIN package. The strain rates were adjusted with Reynolds numbers of premixed syngas-air mixture. Different flame shapes were observed with different strain rates. As strain rate has increased, the flame temperature and axial velocity have been decreased due to the flame heat loss increment, and the OH radical reaction zones become narrower but each mole fractions are still constant. Also, the reversion of $H_2O$ product near stagnation point has been found out when strain rate has increased. This phenomenon is attributed to the rapid production of oxidizing radical reaction such as the R12 ($H+O_2(+M)=HO_2(+M)$), which makes the R18 ($HO_2+OH=O_2+H_2O$) reaction increment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1246-1252
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• 1993

Coal-Water slurry (CWS) is a new potential form of fuel for use in power plants and industrial furnaces. The evaporation and ignition characteristics of CWS have been studied in the post-flame region generated by a flat flame burner. Individual droplets with initial diameters of 1-3mm were supported around the thermocouples and raidly exposed to a hot gas stream. The gas temperature ranged between $950^{\circ}C$ and 1600.deg. C at atmospheric pressure. The effect of droplet size, gas temperature and radiative heat transfer by screen were studied experimentally. The ignition criterion was either a rapid temperature rise in time-temperatuire curves or onset of visible flame in experiment. Incresing the gas temperature or decreasing the droplet size reduced the time required for evaporation and ignition.

• Journal of the Korean Society of Combustion
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• v.1 no.2
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• pp.9-20
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• 1996

We construct a mobile broadband coherent anti-Stokes Raman spectroscopy system to measure the temperature of combustion gases. To improve the accuracy of CARS temperatures due to Stokes lasers, a modeless dye laser is constructed. A monochromator to disperse CARS spectra is also constructed in the spectrometer for easy portability. The accuracy of CARS temperature, measured in graphite tube furnace in reference to a radiation pyrometer, is better than 2 % from 1000 K to 2400 K. The CARS temperature error due to the variation of the spectral distribution of the modeless laser is measured to be less than 1.5 % during five hours operation. As a demonstration of combustion diagnosis, we applied the spectrometer to measure the temperature distribution of the propane air premixed flame.

• Korean Journal of Computational Design and Engineering
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• v.14 no.2
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• pp.129-136
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• 2009

Generally, curved surfaces of ship hull are deformed by flame bending (line heating), multi-press forming, and die-less forming method. The forming methods generate the required in-plane/bending strain or displacement on the flat plate to make the curved surface. Multi-press forming imposes the forced displacements on the flat plate by controlling the position of each pressing points based upon the shape difference between the unfolded flat plate and the curved object shape. The flat plate has been obtained from the unfolding system that is independent of the ship CAD. Apparently, the curved surface and the unfolded-flat surface are expressed by different coordinate systems. Therefore, one of the issues is to find a registration of the unfolded surface and the curved shape for the purpose of minimum amount of forming works by comparing the two surfaces. This paper presents an efficient algorithm to get an optimized registration of two different surfaces in the multi-press forming of ship hull plate forming. The algorithm is based upon the ICP (Iterative Closest Point) algorithm. The algorithm consists of two iterative procedures including a transformation matrix and the closest points to minimize the distance between the unfolded surface and curved surfaces. Thereby the algorithm allows the minimized forming works in ship-hull forming.

• Fire Science and Engineering
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• v.23 no.5
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• pp.78-83
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• 2009

17 kinds of fire resistant paint which are currently used were painted on the MDF, to find flame resistance performance and smoking characteristics according to principal ingredient and characteristics of fire resistant paint. 45 degree combustion test and smoke density test were conducted to investigate the flame resistance performance and smoking characteristics. According to the 45 degree combustion test, acrylic resin type fire resistant paint showed the most excellent fire resistance performance. And the water soluble fire resistant paint showed better fire resistance performance compare to the solvent soluble paints. Also gloss paint showed better fire resistance performance than the flat paint. Based on the smoke density test, the smoke generation of fire resistant treated specimen of acrylic resin type was least. And the water soluble fire resistant paint generate little smoke than solvent soluble fire resistant paint.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.23-29
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• 1999

Experimental studies are conducted to investigate the flame stability and the thermal/fuel NOx formation characteristics of the low calorific value (LCV) coal derived gas fuel. Synthetic LCV fuel gas is produced by mixing carbon monoxide, hydrogen, nitrogen and ammonia on the basis that the thermal input of the syngas fuel into a burner is identical to that of natural gas. The syngas mixture is fed to and burnt with air on flat flame burner. With the variation of the equivalence ratio for specific syngas fuel, flame behaviors are observed to identify the flame instability due to blow-off or flashback and to define stable combustion range. Measurements of NOx content in combustion gas are made for comparing thermal and fuel NOx from the LCV syngas combustion with those of the natural gas one. In addition, the nitrogen dilution of the LCV syngas is preliminarily attempted as a NOx reduction technique, and its effects on thermal and fuel NOx production are discussed.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.1
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• pp.59-71
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• 2014

An experimental study has been conducted to investigate the heat transfer characteristics of laminar syngas/air mixture with 10% hydrogen content impinging normally to a flat plate of cylinder. Effects of impinging distance, Reynolds number and equivalence ratio as major parameters on heat fluxes of stagnation point and radial direction were examined experimentally by the direct photos and data acquisitions from heat flux sensor. In this work, we could find the incurved flame behavior of line shaped inner top-flame in very closed distance between flat plate and burner exit, which has been not reported from general gas-fuels. There were 3 times of maximum and 2 times minimum heat flux of stagnation point with respect to the impinging distance for the investigation of Reynolds number and equivalence ratio effect. It was confirmed that the maximum heat flux of stagnation point in 1'st and 2'nd peaks increased with the increase of the Reynolds number due to the Nusselt number increment. There was a third maximum rise in the heat flux of stagnation point for larger separation distances and this phenomenon was different each for laminar and turbulent condition. The heat transfer characteristics between the stagnation and wall jet region in radial heat flux profiles was investigated by the averaged heat flux value. It has been observed that the values of averaged heat flux traced well with the characteristics of major parameters and the decreasing of averaged heat flux was coincided with the decreasing trend of adiabatic temperature in spite of the same flow condition, especially for impinging distance and equivalence ratio effects.

• Journal of the Semiconductor & Display Technology
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• v.12 no.4
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• pp.45-48
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• 2013

The electronic device, such as flat panel display (FPD), is very important in our life as a means of communication between humans. Liquid crystal display (LCD), which is categorized as a flat panel display, has been used in many display products, especially in TV industry. An LED TV is composed of several electrical components, such as liquid critical module (LCM), analog to digital convertor (AD), power supplier, and inverter board. These modules are very vulnerable to particulate contamination, and causing malfunction or visibility degradation. In this study, we developed a test method for prediction of LCM's lifetime. The test system consists of carbon particle generation flame, dilution system, test chamber, and particle concentration monitoring instrument. Since the carbon particles are the most abundant in the atmosphere and easily absorb light, soot particles are used as a challenging material for this test. The concentration of generated soot particles is set around 4,000,000 #/cc, which is 400 times higher than that of usual atmospheric particles. Through this experiment, we deduced the relationship between the dust concentration and life time of the test specimen.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.278-285
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• 2002

For planar optical devices, silica film deposited by FHD was fabricated at low temperature. To prepare silica film at low temperature, we have changed B, P amounts and investigated consolidation effect with varying consolidation temperature and atmosphere on microstructural change, and also observed optical property. The optimum consolidation temperature in He was lower than that of other atmosphere, its temperature could be lowered to 1050$^{\circ}C$. As a result, the roughness of flat silica film prepared at 1050$^{\circ}C$ showed 5, 6nm.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1550-1557
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• 2002

Diode laser sensor for measuring gas temperature and species concentration in combustion chamber was developed using 2.0 tim distributed feed back lasers. To evaluate the measurement sensitivity of diode laser sensor system, CO2 survey spectra near 2.0 Um were measured and compared with the calculated one. This diode laser absorption sensor was applied to measure gas temperatures in a premixed flat flame of CH$_4$-air mixture. Experimental results were in good agreement with the values by an R-type thermocouple within 6.12%. In addition, successful demonstration of measurement of gas temperature and species concentration in a soot flame showed the promising possibility of diode laser absorption sensors for practical combustion system with non-intrusive method.