• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.22-30
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• 2015

A gas generator which generates turbine driving gas by burning a part of propellants is used in an open cycle liquid rocket engine and as a main component of an open cycle liquid rocket engine autonomous hot firing tests are required to investigate the combustion performance and characteristics of the gas generator. However, since the combustion gas generated by a gas generator is choked at the turbine nozzle in the turbine manifold, it is necessary to consider the internal volume of turbine manifold as well as that of the gas generator for correct investigation of the combustion performance, characteristics, and acoustic characteristics of the gas generator. Therefore, in the paper hot firing test results of a gas generator with a turbine manifold simulator are described and characteristic prediction using the autonomous test of a gas generator is explained.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.808-812
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• 1996

Reduction gear with internal gear pair need functions such as compact size, high reduction ratios, high transmission efficiency, and low noise. Feasible design region of the internal gear pair with a small tooth difference is extremely limited because the internal gear pair is subject to interference in meshing and cutting. Single-objective optimal design can not simulataneously satisfy the manifold requirements of the internal gear pair and can not determine the economical specification of a pinion cutter. Multi-objective optimal design which include the specification of the pinion cutter in design variables is developed, considering the manufacturing error of an internalgear pair and the re-sharpening of the pinion cutter.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.29-33
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• 2010

This study aim to investigate the internal flow characteristics by recess length of swirl coaxial injector for gas generator has propellant of Kerosene-LOx. Recess length is a very important element, have influence in spray stability and LOx post damage. The influence of recess length was analyzed by visualizing internal flow and measuring liquid film thickness and manifold pressures. Also, each spray characteristic by recess length was investigated in internal or external injector.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.751-767
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• 1994

Recent developments of S.I. engine, aiming to higher power, better fuel economy, lower air pollution and better driveability, have much focused on the importance of the role of computer simulation in engine research and development. In this point of view, improving engine performance requires finding some means to improve volumetric efficiency. Up to now there have been several attempts to optimize the intake and exhaust system of internal system of S.I. engine by computer simulation. There appear to be few studies available, however, of such simulation & experimental studies applied to the optimization of exhaust manifold configuration. In this study, gas exchange & power process of 4 cylinder S.I. Engine was studies numerically & experimentally, and governing equation of a one-dimensional unsteady compressible flow and combustion process were respectively solved by a characteristics method and 2-zone model. The aim of this study is to predict and investigate the influence of pressure wave interaction at the exhaust systems on engine performance with widely differing exhaust manifold configuration.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.11
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• pp.834-839
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• 2009

A three-dimensional computational fluid dynamics (CFD) analysis is performed to investigate flow characteristics in the anode channels and manifold of the internal reforming type molten carbonate fuel cell (MCFC). Considering the computational difficulties associated with the size and geometric complexity of the MCFC system, the polyhedral meshes that can reduce mesh connectivity problems at the intersection of the channel and the manifold are adopted and chemical reactions inside the MCFC system are not included. Through this study, the gas flow rate uniformity of the anode channels is mainly analyzed to provide basic insights into improved design parameters for anode flow channel design. Results indicate that the uniformity in flow-rate is in the range of ${\pm}$1% between the anode channels. Also, the mal-distributed inlet flow-rate conditions and the change in the size of the manifold depth have no significant effect on the flow-rate uniformity of the anode channels.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3120-3124
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• 2008

A three-dimensional computational fluid dynamics (CFD) analysis is performed to investigate flow characteristics in the anode channels and manifold of the internal reforming type molten carbonate fuel cell (MCFC). Considering the computational difficulties associated with the size and geometric complexity of the MCFC system, the polyhedral meshes that can reduce mesh connectivity problems at the intersection of the channel and the manifold are adopted and chemical reactions inside the MCFC system are not included. Through this study, the gas flow rate uniformity of the anode channels is mainly analyzed to provide basic insights into improved design parameters for anode flow channel design. Results indicate that the uniformity in flow-rate is in the range of ${\pm}1%$ between the anode channels. Also, the mal-distributed inlet flow-rate conditions and the change in the size of the manifold depth have no significant effect on the flow-rate uniformity of the anode channels.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.5
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• pp.72-77
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• 2007

The combustion test results of the sub-scale combustor having dual swirl injector with internal mixing for a liquid rocket engine are described. The sub-scale combustor uses liquid oxygen(LOx) and kerosene as propellants and has an injector head, an ablative material combustor wall and a water cooled nozzle. The injector head has LOx manifold, fuel manifold, fire face plate, one center swirl injector and 18 main swirl injectors of internal mixing. The combustion tests were successfully performed at design and off-design points without any damages on the injectors. Combustion characteristics velocity of 1756m/s was measured at design point. High frequency combustion instability was not observed but low frequency pulsations occurred at off-design conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.13-18
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• 2010

This study aim to investigate the internal mixing flow characteristics by recess length of swirl coaxial injector for gas generator has propellant of Kerosene-LOx. Recess length is a very important element, have influence in spray stability and LOx post damage. The influence of recess length was analyzed by visualizing internal flow and measuring liquid film thickness and manifold pressures. Also, frequency characteristics were analyzed by liquid film thickness measurement with mixing time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.54-61
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• 2018

Incomplete combustion in automotive engines is a major cause of harmful exhaust gases. In this study, to prevent incomplete combustion and reduce exhaust gas emissions, a gasket blade for increasing the air velocity was applied to the intake manifold, and the change in exhaust gas was investigated theoretically and experimentally. First, simulation analysis for flow according to the number and angle of the gasket blade was performed using a 3D flow analysis program. As an analysis result, the internal average velocity of the gasket blade was optimum at 6-blade with an angle of $30^{\circ}$. Based on the simulation results, experiments were conducted to verify the effects of the gasket blades on the exhaust gas in a non-load engine simulation system. As the engine speed was increased from 2000 to 4000 rpm, exhaust gases of HC, CO, and NOx decreased by 23.4%, 16.5%, and 3.8%, respectively, and the emission decreasing effect was reduced.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.367-376
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• 2008

To obtain the data of the pressure loss and differential pressure at the inside of the stack that was composed of 126 cells with 7,500 cm2 electrode area, 75kW molten carbonate fuel cell system has been operated. Computational fluid dynamics was applied to estimate reactions and thermal fluid behavior inside of the stack that was adopted with internal manifold type separator. The pressure loss coefficient K showed 72.29 to 84.01 in anode and 6.34 to 8.75 in cathode at low part of cells at the inside of 75 kW MCFC stack respectively. Meanwhile, the pressure loss coefficient of the higher part of cells at the interior of the stack showed 15.36 and 56.44 in anode and cathode respectively. These results mean that there is no big total pressure difference between anode and cathode at the inner part of 75 kW MCFC stack. This result will be reflected in 250kW MCFC system design.