• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.44-49
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• 2011

A study of the fatigue life of copper alloy which was used in inner jacket of regenerative cooling chamber of liquid rocket engine has been performed. Generally used life prediction methods -original universal slopes method, modified universal slopes method, Mitchell's method, B$\"{a}$umel and Seeger's method, and Ong's method- have been used for predicting the fatigue data. It was found that the novel life prediction method which was modified from Ong's method was suggested since almost all data have not been predicted well with the widely used methods. The suggested modified Ong's method predicted well within 3X scatterbands.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.570-576
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• 2017

Gas turbine system with steam injection has shown outstanding advantages such as high specific power and NOx reduction. In the present work, a comparative exergetic analysis was carried out for Steam Injected Gas Turbine (STIG), Regenerative Steam Injected Gas Turbine (RSTIG), and Regenerative After Fogging Gas Turbine (RAF). Effects of pressure ratio, steam injection ratio and steam injection method on the system performance was theoretically investigated. The results showed that the order of the highest exergy efficiency is RSTIG, RAF, and STIG for low pressure ratios but STIG, RSTIG, and RAF for high pressure ratios. In each arrangement, the combustion chamber has the highest exergy destruction and the compressor has the second one.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.197-204
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• 2004

A design of regenerative cooling system of 30 ton level thrust combustion chamber for ground test has been performed. The 1-D design code has been validated by comparing with the heat flux of the NAL calorimeter for high chamber pressure and water-cooling performance of the ECC engine of MOBIS. The present design code has been confirmed to predict accurately the heat flux and water-cooling performance for high chamber pressure condition. The maximum hot-gas-side wall temperature is predicted to be about 720 K without thermal barrier coating and the coolant-side wall temperature is less than the coking temperature of RP-1. The coolant temperature rises nearly 100 K with thermal barrier coating when Jet-A1 is used as coolant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.89-92
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• 2010

A study about the fatigue life of copper alloy which is used in inner jacket of regenerative cooling chamber of liquid rocket engine has been performed. Generally used life prediction methods-original universal slopes method, modified universal slopes method, Mitchell's method, Baumel and Seeger's method, and Ong's method-have been used for predicting the fatigue data. It was found that the novel life prediction method which is modified from Ong's method was suggested since almost all data have not been predicted well with the widely used methods. The suggested modified Ong's method predicted well within 3X scatterbands.

• Journal of Auto-vehicle Safety Association
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• v.15 no.3
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• pp.27-33
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• 2023

Electric vehicles are widely produced from many car manufacturers around the world instead of internal combustion engine vehicle in order to respond a variety of environmental regulations. Also, they are applying for modular design method to develop plenty of the vehicles. And, both of these two issues will be an important trend to lead the future global automobile industries for a long time. In this paper, new brake architecture concept is proposed in order to respond to such a situation. First, physical interfaces between brake system like caliper, disc and other counter-parts are established for modular assembly. Second, we analyze effective factors of brake system for electric vehicles which need to reflect vehicle specifications such as total vehicle weight. Here, we consider ideal brake force by critical deceleration. Third, we simulate accumulated regenerative brake energy for two main driving modes to confirm to effectiveness for a variety of Electric Vehicle. Finally, we hope that it contributes to implement brake architecture for the development of Electric Vehicle platform through such a study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.109-116
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• 2005

Elastic-plastic structural analysis for regenerative cooling chamber of liquid rocket thrust chamber is performed. Uniaxial tension test is also conducted for the copper alloy in order to get material data necessary for the structure analysis. The results of uniaxial tension test reveal that copper alloy become ductile after brazing process and flow stress becomes lower as temperature becomes higher. As a result of structural analysis using the material data, the deformation of cooling channel is more increased by thermal load than by internal pressure of cooling fluid. Therefore, the results of analysis show that structural stability and cooling performance of combustion thrust chamber which is designed to endure mechanical load and minimized a channel thickness are improved by decreased thermal load as possible.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.421-425
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• 2009

A study has been performed to investigate the thermo-mechanical effects of thermal barrier coating on liquid rocket regenerative cooling chamber using finite element analysis. Two kinds of thermal barrier coatings were studied on the same loading condition: first, NiCrAlY-$ZrO_2$, coating which is currently applied to the developing combustion chamber and second, Ni-Cr coating which might be applied in the future. Analysis results showed that NiCrAlY-$ZrO_2$ coating has better decreasing effect of temperature than the Ni-Cr coating. As a results, temperature and deformation of the cooling channel in the NiCrAlY-$ZrO_2$ coating were also less than those of the Ni-Cr coating. The Ni-Cr coating has no effect on a structural stability of the outer jacket but the NiCrAlY-$ZrO_2$ coating reduced the effective stress of the outer jacket and enhanced the structural stability of the chamber.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.87-92
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• 2003

In rocket systems, somtimes special devices or equipments are installed near the nozzle exit area where high temperature and pressure combustion gas flows. To pretect these subsystems from severe thermal environment, it is necessary to have accurate thermal data measured from the experimental liquid rocket firing test. Test variables were combustion pressure (200, 300, 400 psi) and mixture ratio (1.5, 2.0, 2.5) and quartz was used as a heat probe. Measurement technique used in this research can be also applied to measure the radiative heat flux inside the combustion chamber which is important imput data for the liquid rocket regenerative cooling system design.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.2
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• pp.51-60
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• 2003

An experimental research program is being undertaken to develop a regeneratively-cooled experimental thrust chamber of liquid rocket engine using liquefied natural gas and liquid oxygen as propellants. Prior to firing test using a regenerative cooling with liquefied natural gas in this program, several firing tests were conducted with water as a coolant. Experimental thrust chambers with a thrust of about 10tf were developed and their firing test facility was built up. Injector used in the thrust chamber was of shear-coaxial type appropriate for propellants of gas and liquid phase and cooling channels are of milled rectangular configuration. Periodical variation of the soot deposition and discoloration was observed through an eyes' inspection on the inner wall of a combustion chamber and a nozzle after each firing test, and an intuitive concept of the periodical variation of mixture ratio near the inner wall of a combustion chamber and a nozzle at once was brought about and analyzed quantitatively. Thermal heat flux to the coolant was calculated and modified with the periodical variation model of mixture ratio, and the increment of coolant temperature at cooling channels was compared with measured one.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.100-109
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• 2006

In the regeneratively cooled combustion chambers using hydrocarbon fuels, coking occurs as the wall temperature increases which generates compounds deposition on the wall. This phenomenon reduces cooling capability of the coolant, finally it can cause damage to combustor by overheating of chamber wall. In this paper electrical heating equipment which is used for the coking experiments and the test results are introduced. The compatibilities of copper alloy with let A-1 were assessed at each condition based on the test results.