• Transactions of Materials Processing
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• v.8 no.1
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• pp.108-115
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• 1999

In this paper, the analysis of cold forging in final state has been performed by using rigid-plastic FEM. For the analysis, the geometry and flow stress of the workpiece are required. One method to obtain the geometry is measurement of that made from experimet. To evaluate the flow stress, average effective strain is calculated from the load-stroke diagram by using energy method. The numerical test performed to show the validity of propose method. The analysis of PFIR, the precision forging of spurgear with inside relif, is performed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.40-45
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• 2005

Techniques used for throcket motors are mainly classified as fixed nozzles with mechanical exhaust jet interferences on the expansion region (such as jet tabs and jet vanes) and movable nozzles(such as ball&socket md flexible seal). Using the numerical analysis and the cold-flow test, this paper evaluates the performance of supersonic nozzle for asymmetric entrance shape at tilted position of ball&socket nozzle. Numerical results show that the asymmetric effects in the flow fields are gradually diminished up to the nozzle throat and are not noticeable downstream of the nozzle throat. Although the calculated thrust and the lateral force are less than those of cold-flow test, two results show a flirty good agreement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.268-271
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• 2008

In order to understand mixing characteristics of the APU combustor, sector combustor which size is 1/6 of the real combustor was manufactured. To see the inner side of combustor, Poly Carbonate material is used as a combustor riner. Turbo blower is used as a air supplying device and valves are used as controling the air flow. Maximum flow rate of the blower is 7 $m^3$/min and maximum inlet velocity is up to 100 m/s.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.69-75
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• 2016

This paper covers the result of construction and start-up tests of the KSLV(Korea Space Launch Vehicle)-II combustion chamber hot-firing test facility. This facility was constructed from 2012 to 2014. Start-up test of this facility began in the second half of 2014. Oxidizer cold flow test, fuel cold flow test and cooling water cold flow test were carried out as start-up test. Afterward, ignition test of combustion chamber was accomplished. The result of ignition test is applied to set up start-up sequence of KSLV-II combustion chamber and utilized as base line data for hot-firing test of low and normal design point.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.38-45
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• 2015

This paper describes an ejector design technique which used for simulating low pressure environment corresponding to high altitude. Also the ejector performance characteristics was investigated according to performance and geometric variables by cold gas flow test. Entrainment ratio, compression ratio and expansion ratio were designated as performance variables and an ejector gap ratio was designated as a geometric variable. A relationship between the performance variables to predict the ejector performance was identified and it was confirmed that the performance variables have much more effective than the ejector gap ratio through the ejector cold gas flow test.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03a
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• pp.49-52
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• 1999

In the present study the tensile test was carried out for steel sheets to offer the database for the material characteristics at various temperature condition. The results are constructed with tensile strength total elongation Lankford vale and the flow curve and these can be employed usefully into the analyzing program as input data for the sheet metal forming processes at warm condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.2
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• pp.62-69
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• 2003

Swirl injectors have the advantage of stable combustion, high efficiency, and insensibility to variable O/F ratio. Recess length is the length from outer orifice tip to inner orifice tip. It is the very important variable of performance of swirl type injector Recess length have influence on collision, mixing, spray, and combustion of propellants. This study investigated on the engine performance with the change of recess length through CFD, cold flow test, and combustion test. In result, we could confirm the change of engine performance with the change of recess length. And we found that performance forecast process through CFD, cold flow test is the right process through combustion test.

• Progress in Superconductivity and Cryogenics
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• v.5 no.1
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• pp.133-135
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• 2003

Cryogenic systems are requirement for the operation of HTS power cables. In general, HTS power cables require temperature below 77K, a temperature that can be achieved from the liquid nitrogen at latm or sub-cooled LN2 above latm. HTS power cable needs sufficient refrigeration to overcome its low temperature heat loading. This loading typically cones in two forms : (1) heat leaks from the surroundings and (2) internal heat generation. This paper explains the cooling test system of 10m HTS power cable. This system is composed of storage dewar, auto fill system, core cryostat and cold-box. Storage dewar is a LN2 storage tank and auto fill system is a LN2 supply device to the sub-cooler, Core cryostat is a LN2 flow line. Cold box is a control unit of temperature and flow rate. It is composed of control valve, flow meter, sub-cooler and circulation pump, etc..

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.602-605
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• 2007

Soybean and rape seed are common feedstocks for biodiesel product ion in USA and Europe, respectively. On the other hand, South Eastern countries like Malaysia and Indonesia have surplus palm crops. However due to substantial amount of saturated fats in palm, the palm biodiesel has poor low temperature properties. To improve the low temperature flow properties as biodiesel, the dependence of the cold filter plugging point (CFPP) on the fatty acid compositions was examined. Two different kinds of biodiesels, palm and soybean biodiesels, were blended with the different volume ratios. And the low temperature flow properties of 0.5%, 1%, and 5% biodiesel in diesel blend fuels was tested. The decrease of CFPP was not observed for BD1 with Palm BD. Also, WDI test didn't exceed in the range of 4oC by the mixing of Palm BD upto 5% in commercial diesels.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.1067-1072
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• 2011

If the flow of booster gas which is exhausted to the rear part of a canister is properly restricted in the canister of a hot-launch system, the resultant pressure built up in the canister provides additional force to accelerate the missile to a required launch velocity. These thrust augmentation performances can be controlled through the configuration design of baseplate orifices. In this paper, the simple technique to analyze the thrust augmentation performances of baseplate orifices is suggested and the thrust augmentation characteristics by its various configurations are compared. According to the initial displacement of a missile, the inner pressure of a canister is measured from scaled cold flow tests, and the discharge coefficient of baseplate orifices is calculated. Then the thrust augmentation in a canister is simulated by applying these discharge characteristics to the AMESIM software for launch dynamics.