• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.58-63
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• 2005

As fuel cells approach commercialization, hydrogen production becomes a critical step in the overall energy conversion pathway. Reforming is a process that produces a hydrogen-rich gas from hydrocarbon fuels. Hydrogen production via autothermal reforming (ATR) is particularly attractive for applications that demand a quick start-up and response time in a compact size. However, further research is required to optimize the performance of autothermal reformers and accurate models of reactor performance must be developed and validated. The design includes the requirement of accommodating a wide range of experimental set ups. Factors considered in the design of the reformer are capability to use multiple fuels, ability to vary stoichiometry, precise temperature and pressure control, implementation of enhancement methods, capability to implement variable catalyst positions and catalyst arrangement, ability to monitor and change reactant mixing, and proper implementation of data acquisition. A model of the system was first developed in order to calculate flowrates, heating, space velocity, and other important parameters needed to select the hardware that comprises the reformer. Predicted performance will be compared to actual data once the reformer construction is completed. This comparison will quantify the accuracy of the model and should point to areas where further model development is required. The end result will be a research tool that allows engineers to optimize hydrogen production via autothermal reformation.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.320-327
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• 2005

An experimental study was performed to investigate the effects of partially premixing, varying the equivalence ratios from $1.36{\sim}{\infty}$, and swirlers with swirl numbers of 0, 0.28, 0.64, and 1.32, on the characteristic of radical ($OH^{\ast}$, $CH^{\ast}$, and $C_2^{\ast}$) and pollutant emission in partially premixed swirling flames. The signal from the electronically excited state of $OH^{\ast}$, $CH^{\ast}$, and $C_2^{\ast}$ was detected through a band pass filter with a photo multiplier tube, and flow fields images were detected through a schlieren system. The results demonstrated that the flame height decreases and jet spreading angle increase with increasing a swirl number. The more momentum ratio and swirl number increase, the more decrease flame height, and the generation of sooting flame is promoted.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.231-237
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• 2005

Interruption of good fluidization in a fluidized bed ash cooler(FBAC) for discharging bed materials such as sand or coal ash particles from the CFB combustor is frequently happened because of agglomeration of the particles in the bed. This unstable operation may, in the worst case, result in an unscheduled boiler shut down. In this study, we examined the operation problems of the FBAC of Tonghae CFB boiler and studied and introduced the simple detection and solution techniques with analyzing the mixing property and the occurrence of defluidization in a simulated fluidized bed ash cooler system (0.5m-H x 0.5m-W x 1.0m-L). The bridge of the large particles at the bed surface could be observed, and this caused to form the defluidization area at the entrance of the FBAC. The defluidization was affected not only by airflow rates but also by the particles discharging rates as well as particle size distribution in the FBAC. The local defluidization could be detected by analysis of the accumulated standard deviation error at a given period of time. Also, the regulation of the overall or local airflow rate made clearing up the local defluidization possible.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.107-110
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• 2009

A basic design for a Technical Development Model (TDM) of liquid oxygen lines from the turbopump exit to the oxidizer valves of the combustion chamber and the gas generator was conducted to develop a turbopump-fed liquid rocket engine. The TDM is composed of straight lines, elbows, bellows, a branch, an orifice, flanges and a heat insulator. Materials were determined by consideration of operation conditions, weight constraint and manufacturing procedures. The size and the location of each component were determined by flow analysis of the required flowrate and the pressure loss. Basic designs of the components were conducted by consideration of the operating temperature and the maximum expectation operating pressure. The safety factors were evaluated by structural analysis of design of each component.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.213-216
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• 2009

In order to see the flame behavior in the gas turbine combustor, combustion test was performed by using sector combustor. Ignition test with torch ignition system was carried out at the various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with fixed air mass flow rate. In the test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet air velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity.

• Journal of Hydrogen and New Energy
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• v.18 no.4
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• pp.406-412
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• 2007

An experimental study on the design of a catalytic combustor for 1.6 kW MCFC system has been performed. The roles of the catalytic combustor are to completely burn anode off-gas and to supply sufficient $CO_2$ to cathode channels. In order to avoid hot spot or fuel slippage, flow uniformity at the catalyst inlet was achieved by installing two crossing perforated plates between the catalyst and the mixing chamber with minimal pressure drop. A Pd/Ce/Ni-$Al_2O_3$ catalyst was used for complete combustion of the off-gas at GHSV=36,000.

• Journal of Environmental Science International
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• v.16 no.1
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• pp.9-19
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• 2007

Comparing predicted PCDF isomer patterns with those obtained from a municipal waste incinerator assessed the role of two-phenol condensation pathways in the formation of PCDFs. Complete PCDF homologue and isomer distributions were obtained from a Fluidized Bed Incinerator (FBI). Two-phenol condensation model, dependent only on the distributions of phenols, was developed to predict the PCDF congeners produced from phenol precursors. R-squared values from linear correlations are presented for the dichlorinated through hexa-chlorinated isomer distributions between measured and predicted. They range from 0.00: to 0.1 far the di-chlorinated through hexa-chlorinated isomer sets. Agreement between predicted and measured PCDF isomer distributions was very poor for all homologues. Two-phenol condensation pathways are not likely to be the pre-dominant pathways in the formation of PCDF in a FBI. However, dibenzofuran (DF) is likely to be produced from a condensation of two phenols. This work demonstrates the use of PCDF homologue and isomer patterns for testing PCDF formation mechanism from two-phenol condensation pathways in municipal waste incinerators.

• Journal of Hydrogen and New Energy
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• v.8 no.1
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• pp.5-10
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• 1997

Because of environmental pollution and reserve limitations of fossil fuels, several alternative energies have been developing. One of them, the hydrogen is researched as a highly probable solution. In this study pure hydrogen gas and oxygen gas are burned in combustor to reduce the emission, and a gas turbine is used. Cooling water around the combustor recovers the cooling heat loss to useful work by being expanded from liquid to vapor, being injected into the combustor and making pressure rise with working fluid to get more turbine power. Because pure hydrogen and oxygen are used, there is no carbonic emission such as CO, $CO_2$, HC nor $NO_x$, and $SO_x$. The power is obtained by turbine system, which makes lower noise and vibration than any reciprocating engine. Running of a turbine is searched under various conditions of hydrogen flow rate and water injection rate. Maximum speed of the turbine is obtained when the combustion reaches steady state. It is enable to determine the optimum rate between hydrogen flow and water injection which makes turbine run maximum speed.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.93-100
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• 2017

Four-stroke cycles in an automobile engine are suction stroke, compression stroke, combustion stroke and exhaustion stroke. A normal operation of engine in compression and power stroke must be processed in optimal fuel-air pressure. In this paper we describe a development of measuring equipment for engine cylinder pressure with observing supply current to self motor(start motor). By comparing the current wave on pressure of the 4 or 6 cylinder in engine, a abnormal cylinder state will be found. The validity of the proposed measuring equipment was shown by experiment for real automobile.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.7
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• pp.905-914
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• 2001

A large eddy simulation(LES) is performed for turbulent flow around a bluff body inside a sudden expansion cylinder chamber, a configuration which resembles a premixed gas turbine combustor. To promote turbulent mixing and to accommodate flame stability, a flame holder is installed inside the combustion chamber. The Smagorinsky model is employed and the calculated Reynolds number is 5,000 based on the bulk velocity and the diameter of the inlet pipe. The simulation code is constructed by using a general coordinate system based on the physical contravariant velocity components. The predicted turbulent statistics are evaluated by comparing them with the laser-doppler velocimetry (LDV) measurement data. The agreement of LES with the experimental data is shown to be satisfactory. Emphasis is placed on the time-dependent evolutions of turbulent vortical structure behind the flame holder. The numerical flow visualizations depict the behavior of large-scale vortices. The turbulent mixing process behind the flame holder is analyzed by visualizing the sectional views of vortical structure.