• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.904-907
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• 2011

Various types of gases and propellants are used in launch vehicle. In order to fulfill the mission of the launch vehicle, the components and systems used in launch vehicle should ensure flawless operation in these environments. The pneumatic test is the test performed using compressed gas to prove requirements of the components and systems. This paper describes the requirements of the gas quality for pneumatic test, leak test method, and pneumatic test of the launch vehicle.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.82-87
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• 1998

The opening temperature of emit heat, caloric value and decomposition hear were investigated by DSC & TGA in order to find the hazard of sanitary feed-stuff, also explosion hazard of dust was observed with electrical ignition after fodder dispersion by compressed air. Then opening temperature of emit heat of supporting gas. $O_{2}$ was much lower than inert gas. Ar. and caloric value increased 20. and the particle size of sanitary feed-stuff were appeared fire or explosion at 50/60 mesh and 60/80 mesh.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.749-755
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• 2011

The performance and emission characteristics of a CNG (compressed natural gas) engine were experimentally investigated under different natural gas compositions. The engine specifications were as follows: 6606 cc, turbo, lean-burn-type; its ignition timing was fixed for the fuel gas with a HHV (higher heating value) of 10454 kcal/$Nm^3$. The experimental results showed that when the HHV of the fuel gas was changed from 10454 kcal/$Nm^3$ to 9811 kcal/$Nm^3$ and 9523 kcal/$Nm^3$, the average power reductions were 3.2 % and 3.4 % (1.5 % and 2.1 %, respectively, with A/F control switched off), respectively, and the average thermal-efficiency reductions were 1.1 % and 1.5 % (1.5 % and 2.1%, respectively, with A/F control switched off), respectively. The emissions of $CO_2$, CO, and $NO_x$ decreased as the HHV of the fuel gas was lowered. On the other hand, the emissions of THC (total hydrocarbon) were not consistent, and the extent of change in their emissions was small.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.3
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• pp.90-96
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• 1995

In general, natural gas engine converted from gasoline engine has disadvantage of power decrease. In order to increase power output in natural gas engine, the improvement of in-cylinder flow motion has been believed as the most effective method. In this study, the geometry of combustion chamber in 4 valve DOHC natural gas engine is modified, and in-cylinder flow patterns is analyized. Also engine performance is evaluated according to the modification of in-cylinder flow motion.

• Journal of the Korean Society for Precision Engineering
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• v.1 no.2
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• pp.47-57
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• 1984

The porous matterials are used both to control the flow of the compressed gas and to serve as the bearing surface. This porous design offers several advantages over the conventional externally pressurized gas bearings. It can simplify the construction, lower the gas consumption, and make the cleaning of the gas supply less critical. Test apparatus was cinstructed to experi- mentally investigate maximum load capacity of thrust bearing was measured 200 Kg (15Kg/$\mu$m), and radial bearing was 36 Kg/$\mu$m. And a rotation accuracy of face waving was 0.0127$\mu$m, and center waving was measured 0.5 $\mu$m. Finally, the use of this method of design and manufacturing will contribute to many practical application in the field required for precision and high stability.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.16-21
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• 2003

Natural gas is one of the promising alternative fuels because of the abundant deposits and the cleanness of emission gas. It can be used in conventional gasoline engine without major modification. Natural gas has some advantages than gasoline i.e. the high octane number, good mixing condition because of gas and wide inflamable limit. In the present study, a $1.8{\ell}$ conventional gasoline engine is modified for using the CNG as a fuel instead of gasoline. Performance and emission characteristics are compared between gasoline and CNG with 4 cylinder SI Engine which is controlled by programable ECU. Parameters of experimentation are equivalence ratio, spark timing and fuels. We analyzed the combustion characteristics of the engine using the cylinder pressure i.e. ignition delay, combustion duration and cycle variation. As a result, CNG engine shows lower exhaust emissions but brake torque is slightly reduced compared to gasoline engine. Overall combustion duration is longer than that of gasoline because of lower burning speed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.156-161
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• 2005

Dynamic flow characteristics of a solenoid valve are affected by pressure difference in inlet and outlet of orifice, gas temperature, and supply voltage of a coil. In this paper, the dynamic flow characteristics for deviations of various conditions are studied Static and dynamic flow for variation on-time of a solenoid valve open signal are measured in basic bench test. The solenoid valve is applied to a compressed natural gas(CNG) engine test for validation of flow control performance. The experimental results show that flow of high pressure gas can controlled precisely by using a solenoid valve.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2984-2988
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• 2008

Numerical analyses are carried out in order to understand complex thermal characteristics of a gas turbine combustor liner such as combustion gas temperatures, wall temperatures and heat transfer distributions. As results, The maximum internal and external heat transfer is $2218W/m^2K$ and $2358W/m^2K$, respectively. The combustion gas temperatures range is 673K to 1760K. A range of temperature on TBC is 676K to 1382K. Lastly, temperature range on outer surface of combustion liner cooled by compressed air is 676K to 1188K.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.857-858
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• 2012

• 한국가스학회:학술대회논문집
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• 2004.11a
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• pp.91-96
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• 2004