• Transactions of the Korean hydrogen and new energy society
• /
• v.28 no.2
• /
• pp.181-189
• /
• 2017

This paper describes experimental results on combustion characteristics with hydrogen contents of synthetic natural gas (SNG) in low swirl combustor. To investigate the effect of hydrogen contents for premixed SNG flame, stability map, CH chemiluminescence images, flame spectrum analysis and emission performances were measured. In the results, as the hydrogen content was increased, the lean flammable limit was expanded and the flame length was decreased. The hydrogen contents affected the flame liftoff height, and it has different tendency according to the equivalence ratio and flame shape. The change of height and length of flame according to hydrogen contents is caused by the fast burning velocity of hydrogen, which can be confirmed by GRI 3.0 reaction mechanism in PREMIX code. The intensity of $OH^*$, $CH^*$ and $C_2^*$ was confirmed by spectrum analysis of flame. As a result, the $CH^*$ intensity was not significantly different according to hydrogen content. The increase of hydrogen contents influenced positively CO and NOx emission performances.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.58-65
• /
• 2004

A cylindrical constant volume combustion chamber was used to investigate the combustion characteristics of stratified methane-air mixture under several initial charge conditions in the author's previous reports. The results showed that the improvement of thermal efficiency and reduction of heat loss was realized simultaneously by using 2-stage injection method. This paper deals with the reason why the stratified combustion has showed better combustion rate through the measurement and analysis of chemiluminescence of C $H^{*}$ and $C_{2}$$^{*}$ radicals. An optic fiber bundle is used to measure the local emission of C $H^{*}$ and $C_{2}$$^{*}$ radicals to map the relationship between the excess air ratio and local radical intensity ratio in the combustion vessel at 5 mm apart form the geometric center. The results show that there exist a relationship between the intensity ratio and the air-fuel ratio. It is revealed that the improvement of combustion rate in a lean-stratified mixture is realized through the 2-stage injection method. method.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.1
• /
• pp.1-8
• /
• 2019

To analyze the dynamic behavior and the structure of the gaseous methane-gaseous oxygen diffusion flame formed by a swirl/shear-coaxial injector, combustion experiments were carried out under different propellant injection conditions. As a result, the OH radical emission intensity of the diffusion flame visualized through chemiluminescence was observed to increase as the propellant mass flow and the momentum flux ratio increased. And flames with swirl showed a more high radical emission intensity than those without swirl.

• Journal of Mechanical Science and Technology
• /
• v.18 no.10
• /
• pp.1859-1868
• /
• 2004

Monitoring of OH chemiluminescence through an optical fiber was demonstrated to be a useful method in detecting self-excited combustion oscillations. OH chemiluminescence intensity detected by the optical fiber showed mostly excellent agreement with those obtained by high speed CCD camera measurements when combustion oscillations were strong. Symptoms of self-excited combustion oscillation were also studied in order to predict the onset of combustion oscillation before it proceeded to a catastrophic failure. For the purpose, we have found and proposed unique measures to tell the onset of self-excited combustion oscillations based on the careful statistics of fluctuating properties in flames, such as pressure or emission of OH radicals.

• Archives of Pharmacal Research
• /
• v.28 no.3
• /
• pp.358-363
• /
• 2005

We have studied the interaction of 3-nitrotyrosine with peroxynitrite using three different methods; chemiluminescence, spectrophotometry and HPLC. Peroxynitrite-induced luminol or lucigenin chemiluminescence were significantly decreased by 3-nitrotyrosine, in concentration­dependent manners. The intensity of the peroxynitrite spectrum was also markedly reduced in the presence of 3-nitrotyrosine in the spectrophometric assay. However, there was no attenuation of the 3-nitrotyrosine signal in the HPLC assay after mixing with peroxynitrite. The interaction of 3-nitrotyrosine and hypochlorous acid (HOCI) was also studied via the chemilumines-cence assay, where the HOCI-induced responses were markedly inhibited by 3-nitrotyrosine. These results suggest that caution should be taken when studying the levels or interactions of 3-nitrotyrosine.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.11
• /
• pp.1368-1375
• /
• 2004

Measurements of OH chemiluminescence in an atmospheric pressure, laboratory-scale dump combustor at equivalence ratios ranging from 0.63 to 0.89 were reported. The signal from the first electronically excited state of OH to ground state was detected through a band-pass filter with an ICCD. The objectives of this study are two: One is to see the effects of equivalence ratio on global heat release rate and local Rayleigh index distribution. To get the local Rayleigh index distribution, the line-of-sight images were inverted by tomographic method, such as Abel do-convolution. Another aim is to investigate the validity of using OH chemiluminescence acquired with an ICCD as a qualitative measure of local heat release. For constant inlet velocity and temperature, the overall intensities of OH emission acquired at different equivalence ratio showed periodic and higher value at high equivalence ratio. OH intensity averaged over one period of pressure increased exponentially with equivalence ratio. Local Rayleigh index distribution clearly showed the region of amplifying or damping the combustion instability as equivalence ratio increased. It could provide an information/insights on active control such as secondary fuel injection. Finally, local heat release rate derived from reconstructed OH images were presented fur typical locations.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.4
• /
• pp.276-282
• /
• 2008

The effects of hydrogen enrichment to methane have been investigated with swirl-stabilized premixed hydrogen-enriched methane flame in a laboratory-scale pre-mixed combustor. The hydrogen-enriched methane fuel and air were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for different amount of hydrogen addition to the methane fuel and different swirl strengths. The hydrogen addition effects and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using micro-thermocouple, particle image velocity meter (PIV) and chemiluminescence techniques to provide information about flow field. The results show that the flame area increases at upstream of reaction zone because of increase in ignition energy from recirculation flow for increase in swirl intensity. The flame area is also increased at the downstream zone by recirculation flow because of increase in swirl intensity which results in higher centrifugal force. The higher combustibility of hydrogen makes reaction faster, raises the temperature of reaction zone and expands the reaction zone, consequently recirculation flow to reaction zone is reduced. The temperature of reaction zone increases with hydrogen addition even though the adiabatic flame temperature of the mixture gas decreases with increase in the amount of hydrogen addition in this experiment condition because the higher combustibility of hydrogen reduces the cooler recirculation flow to the reaction zone.

• Journal of the Korean Chemical Society
• /
• v.46 no.6
• /
• pp.509-514
• /
• 2002

A method to determin Fe(II) and Fe(III) ion in aqueous solution by chemiluminescence method using a stopped flow system has been studied. The method is based on the increased chemiluminescence intensity with the addition of Fe(III) ion to a solution of lucigenin and hydrogen peroxide. The effects of KOH concentration, flow rate of reagents, $H_2O_2$ concentration and citric acid concentration used for the masking of Fe(II) ion on the chemilu-minescence intensity have been investigated. The calibration curve for total Fe was linear over the range from 1.0${\times}$$10^{-6}$ M to 1.0${\times}$$10^{-4}$M, coefficient of correlation was 0.996 and the detection limit was 1.0${\times}$$10^{-7}$M under the optimal exper-imental conditions of 4.0 M, 2.0 M, 3.5 mL/min for the concentration of $H_2O_2,$ KOH and flow rate of reagents, respec-tively. The calibration curve for Fe(Ⅲ) was linear over the range from 1.0${\times}$$10^{-6}$M to 1.0${\times}10^{-4}$ M, the coefficient of correlation was 0.997 and the detection limit was 5.0${\times}$$10^{-7}$M under the optimal experimental conditions.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3199-3205
• /
• 2013

The inclusion behavior of sulfobutylether-${\beta}$-cyclodextrin (SBE-${\beta}$-CD) with perphenazine (PPH) was first studied by flow injection (FI)-chemiluminescence (CL) analysis with proposed $lg[(I_0-I_s)/I_s]=lgK_{P-CD}+nlg[C_{PPH}]$ model and molecular docking. Results showed that a 1:1 complex of SBE-${\beta}$-CD/PPH could online form, with the formation constant $K_{P-CD}$ of $2.57{\times}10^7Lmol^{-1}$ at 298 K. The thermodynamic parameters showed that the inclusion behavior of SBE-${\beta}$-CD/PPH was a spontaneous process by hydrophobic interaction. The molecular docking results revealed PPH entered into the larger cavity of SBE-${\beta}$-CD with two hydrogen bonds. Based on the linear relationship of the decrement of luminol/SBE-${\beta}$-CD/PPH CL intensity against the logarithm of PPH concentration ranging from 0.03 to 30.0 ng $mL^{-1}$, the present FI-CL analysis using luminol/SBE-${\beta}$-CD/PPH system was successfully applied to PPH determination in biological fluids and tablets with recoveries from 94.5 to 105.6% and RSDs less than 2.6% (n = 5).

• Analytical Science and Technology
• /
• v.21 no.1
• /
• pp.20-24
• /
• 2008

A chemiluminescence method has been developed to determine vitamin $P_1$ in aqueous solution which is based on the enhancement of the intensity of lucigenin using lucigenin-$H_2O_2$ as chemiluminogenic system. The effects of experimental parameters such as concentrations of lucigenin, pH and concentrations of $H_2O_2$ were studied. The present method allows the determination of vitamin $P_1$ over the range $7.5{\times}10^{-6}{\sim}5.0{\times}10^{-4}mol/L$. The detection limit was $5.7{\times}10^{-7}mol/L$. The relative standard deviation was 0.75 % for 10 determinations of $7.5{\times}10^{-5}mol/L$ vitamin $P_1$. The correlation coefficient of the working curve was 0.9984 (S/N=3).