• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.180-185
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• 2004

Our previous study showed that although the hybrid rocket engine with swirling gaseous oxygen had high performance, a direct injection of LOX with swirl into the combustion chamber of the hybrid rocket engine lowered the performance of the engine, compared to that with gaseous oxygen. In order to clarify this reason, combustion tests of a small PMMA combustor with an inner port diameter of 2 mm were conducted in liquid oxygen flow by comparison with gaseous oxygen flow. Although the oxygen mass fluxes of LOX were about two orders of magnitude larger than those of gaseous oxygen, the fuel regression rate of LOX were remarkably smaller than those of gaseous oxygen. For both liquid and gaseous oxygen, diffusion flames in the port of the grain controlled the combustion process of PMMA in oxygen flow. These results may be explained by the fact that only small amount of LOX vaporized and consumed in the combustion with PMMA while flowing through the port due to relatively larger latent heat of injected liquid oxygen compared to the heat of release by combustion which depended on the burning surface area of PMMA.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.211-215
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• 2004

For design of cryogenic propellant feeding system, one of the main requirements is to meet temperature requirement for satisfying turbo-pump NPSH requirement. In this paper improved method of estimating the thermal stratification in liquid oxygen tank is presented to help design. In the case of liquid rocket using turbo-pump, the inner pressure of liquid oxygen tank is maintained low, so vaporization of liquid oxygen is generally occurred. In this paper, inner process of LOX tank is analyzed by two phase flow modeling. The vaporization rate and required helium mass is investigated.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.262-265
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• 2004

As a cryogen, LOx is a light blue, odorless, transparent liquid. Also it is not shock sensitive and does not decompose. However, it is a strong oxidizer and will vigorously support combustion. Therefore all harmful contaminants (such as grease, oil, fingerprint and organic materials) that could cause malfunctions, fires, or explosions in a oxygen environments must be completely removed prior to the introduction of oxygen. Especially, grease ingredient located inside of the LOx supply line, pipe and PHS (Pneumo-Hydraulic System) part can make drastic chemical reaction with oxygen. Therefore, to protect rapid reaction such as explosion, grease ingredient must be surely eliminated by a regular and irregular degreasing. Study on the availability, effectiveness and selection of degreasing detergents and method is described in this paper, and it will be useful for the construction and management of IPP test facility.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.4
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• pp.440-446
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• 2003

Steady-state structure and acoustic pressure responses of GH$_2$-LOx diffusion flames in stagnation-point flow configuration have been studied numerically with a detailed chemistry to investigate the acoustic instabilities. The Rayleigh criterion is adopted to judge the instability of the GH$_2$-LOx flames from amplification and attenuation responses at various acoustic pressure oscillation conditions for near-equilibrium to near-extinction regimes. Steady state flame structure showed that the chain branching zone is embedded in surrounding two recombination zones. The acoustic responses of GH$_2$-LOx flame showed that the responses in near-extinction regime always have amplification effect regardless of realistic acoustic frequency. That is, GH$_2$-LOx flame near-extinction is much sensitive to pressure perturbation because of the strong effect of a finite-chemistry.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.90-98
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• 1998

The vaporization process of liquid oxygen(LOX) at high pressure environment is numerically investigated. The present vaporization model can account for the high-pressure effects such as ambient gas solubility, real gas behavior and variable properties. The predicted phase-equilibrium compositions for $N_2$/$H_2$ and $O_2$/He system are well agreed with experimental data. The LOX vaporization characteristics is parametrically studied for wide range of the operating conditions encountered in the high-pressure combustion process of liquid rocket engine.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.41-46
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• 2006

A study was conducted to investigate the problem caused by the mechanical particles in LOX system during operating and testing propulsion system, especially concentrated on effects of contaminants accumulation and transfer in LOX system. Several methods for system operation decreasing accidents caused by oxidizer Beakage and contaminants accumulation was investigated. These methods can be applied to LOX system and other propellants system in liquid propellants propulsion system.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.6
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• pp.91-100
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• 2016

Efficiency characteristics of centrifugal turbopumps for a liquid rocket engine were investigated. Predicting the performance of pumps for a turbopump assembly test, the variation on pump efficiency by working fluids was analyzed from pump component tests. Water and liquid nitrogen (LN2) were used for the component test, kerosene (Jet A-1) and liquid oxygen (LOX) were adapted for the turbopump assembly (TPU) test as working fluids. Overall performance of the pumps was investigated covering design/off-design operating points and the pump efficiency on the environment of real media (LOX/kerosene) could be modified from the pump component tests.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.363-367
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• 2009

For the liquid rocket propulsion system using liquid oxygen as oxidizer, helium for pressurizing LOX is usually stored in the LOX tank with cryogenic temperature. For that kind of pressurizing system, cryogenic helium is discharged from the immerged pressurant cylinder and passes through the heat exchanger downstream of gas generator. During the process, helium pressurant is heated from cryogenic temperature to high one and supplied to the ullage of propellant tank. To develop the pressurizing system, a cryogenic heating apparatus is needed to simulate the heat exchanger. In this paper, the cryogenic heating apparatus for development of the pressurization system is presented along with its heating test results with cryogenic helium.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.63-68
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• 2011

For the liquid rocket propulsion system using liquid oxygen as oxidizer, helium for pressurizing LOX is usually stored in the LOX tank with cryogenic temperature. For that kind of pressurizing system, cryogenic helium is discharged from the immerged pressurant cylinder and passes through the heat exchanger downstream of gas generator. During the process, helium pressurant is heated from cryogenic temperature to high one and supplied to the ullage of propellant tank. To develop the pressurizing system, a cryogenic heating apparatus is needed to simulate the heat exchanger. In this paper, the cryogenic heating apparatus for development of the pressurization system is presented along with its heating test results with cryogenic helium.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.279-282
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• 2006

Upon a turbopump's running, cavitation may occur at the inlet of the LOx pump by pressure drop and heat transfer along the LOx feeding line. Since the cavitation can cause serious damage to the pump or to stop running, the absence of the cavitation at the inlet of a turbopump should be confirmed before the using the turbopump. In the present study, the calculation of the volume fraction of LOx gas phase at the inlet of the pump are performed with different temperatures of LOx in the tank, pressure drops and heat transfers along the feeding line. This calculation method can be applied to define the limits of thermal and hydraulic characteristics during the design of a LOx feeding system.