• Journal of the korean Society of Automotive Engineers
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• v.27 no.3
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• pp.14-18
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• 2005

• Geotechnical Engineering
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• v.23 no.11
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• pp.32-45
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• 2007

• Proceedings of the Korean Nuclear Society Conference
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• 2003.10a
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• pp.240.1-240.1
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• 2003

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.128-134
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• 2007

Combustion performance and characteristics of high-pressure subscale liquid rocket combustors were studied experimentally. Four different models of combustor were considered in this paper. The high-pressure subscale combustor is composed of the mixing head, the water cooling cylinder and the nozzle. One model of the combustors employed regenerative cooling combustor in that the kerosene used for the chamber cooling is burned. This combustor was damaged due to a high frequency combustion instability occurred during a firing test. The results of the firing tests, comparison of performance, and characteristics of static and dynamic pressures of the combustors are described.

• Geotechnical Engineering
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• v.12 no.4
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• pp.33-46
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• 1996

When structures are constructed in ground with poor bearing capacity, deformation of ground may induce foundation settlements and cracks of structures. Recently, high pressure jet grouting is widely used to improve the engineering properties of such foundation. Sometimes, the grouting columns are built in the ground by jet grouting method. They are used as in -situ piles to increase the bearing capacity of existing foundation. In this paper, as for the grouting columns built in ground by high pressure jet grouting with double tube rod, the effects on reinforcement and bearing capacity of ground are investigated. A series of laboratory tests has been performed on the specimens sampled from the grouting columns and a pile load test has been performed on a grouting column. The test results show that high pressure jet grouting has a sufficient effect on reinforcement of ground and restraint of settlement of structure.

• Geotechnical Engineering
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• v.12 no.5
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• pp.5-16
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• 1996

When braced excavation with temporary retaining wall installation, is performed in loose sand with high ground water level boiling may be induced and considerable damage on the excavation works and structures in the vicinity can take place. Recently, for the purpose of reinforcement of ground and cut-off of ground water behind the temporary retaining wall, high pressure jet grouting is widely used. The purpose of this paper is to investigate the effects of jet grouting on ground reinforcement and cut -off of the ground water behind temporary retaining walls for braced excavation. A series of both laboratory and field tests has been performed. The test results show that high pressure jet grouting has sufficient effects on reinforcement of stiffness of ground and retaining wall. The permeability of the improved ground was 10-f_ 10-3cm l s smaller than those of the original ground. Therefore, the effect on cut off of ground water behind temporary retaining walls could be improved by high pressure jet grouting method.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.68-77
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• 2010

In the case of operating steam generators for long periods in nuclear power plants, sludge is accumulated inside the steam generator. This phenomenon could adversely affect the operation of the steam generator. This paper is about the design of a sludge washing apparatus which can remove the sludge efficiently and the control methods of the apparatus. In this paper, to design the sludge washing apparatus, firstly, we design nozzles for spraying high-pressure water through applying mathematical models and lab tests. Secondly, we establish the mathematical theory for performance parameters required to drive the sludge washing apparatus. Thirdly, we design physical structures of the apparatus based on the established performance parameters. Finally, we present the control methods of the apparatus. The sludge washing apparatus presented in this paper moves along the walls of the steam generator according to cracks in the tube array, and spray the high pressure water to remove the sludge. By this way, a relatively large amount of sludge formed in the inner surfaces can be washed very effectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.637-642
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• 2017

In this study, cold flow and combustion tests are conducted and analyzed to validate designed rocket engine head generating high temperature/pressure steam. At first, uni-injector was designed and manufactured, and cold flow test was conducted. Through this, differential pressure that can supply designed flow rate was confirmed. Also, Each injector's spray pattern were confirmed by patternator. Based on cold flow test results, we selected injectors among the candidates and arranged them on engine head, and cold flow and propellant spray tests were conducted. Finally, combustion test was carried out to analyze the flow rate, pressure, combustion efficiency. As a result, validation of rocket engine head for the development of the high temperature and high pressure steam generator has been completed.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.3
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• pp.1-6
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• 2007

A 3-tonf-class high pressure sub-scale combustor was designed and manufactured to study the performance improvement of combustor. The combustor consists of a combustion chamber with film cooling, thermal barrier coating and water cooling channels to prevent thermal demage of the hardware and an injector head with 37 coaxial swirl injectors. Hot-firing tests were carried out at the design point with varying flow rate for film cooling. The test result revealed that the increase of film cooling flow rate decreases the combustion performance, but in the cases of similar film cooling flow rates, the combustion performance is dependent on the mixture ratio of main injector excluding the film cooling flow rate.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.135-141
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• 2005

The procedure of conceptual and detailed design of sub-scale combustor using bipropellant swirl or impinging injector with external or internal mixing for a liquid rocket engine are described in this paper. The sub-scale combustor uses liquid oxygen(LOx) and kerosene as propellants and has a 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 or impinging injector and 18 main swirl or impinging injectors.