• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.2147-2159
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• 1991

The effects of principal dimensions of internal mixing twin-fluid atomized and operating conditions on the atomizing characteristics are experimentally investigated. The tests are conducted over the wide range of air/liquid ratio to predict influences of the diameter and length of nozzle, contacting angle between air and liquid in the mixing chamber, and air orifice diameter on the mean drop size(SMD), spray angle, distribution of drop size, and spray dispersion, And also, initial distribution of liquid column by air stream within the mixing chamber are observed through the transparent nozzles. A He-Ne laser particle sizer(MALVERN Model 2604) was used to measure the Sauter.s mean diameter( $D_{321}$) and droplet sizes distribution. In this experiment the air/liquid ratio, mixing length and nozzle diameter have a great influence on SMD, spray angle, droplet sizes distribution and spray dispersion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.41-47
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• 2006

A liquid rocket thrust chamber should have a high confidence in its combustion performance and combustion stability. Expecially, the injector of which function is spraying and mixing propellants plays an important role in getting the confidence. This study was carried out to evaluate combustion stability of a double swirl coaxial injector by using the model similarity method. Besides, in case of a baffle which was used to improve combustion stability, the length and gap effects of the baffle were investigated.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.1-9
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• 2004

The flow in the LOX manifold of liquid rocket (KSR-III) has been analyzed using a CAE technique with an objective of modeling injector orifices in order to reduce the computational cost for the flow analysis without much losing the accuracy of capturing the flow physics. The numerical result shows that the flow just above the injector orifices is not uniformly distributed in terms of pressure and mass flow rate in case pre-distributors are not equipped inside the manifold. This non-uniformity of mass flux is attributed to the presence of large-scale flow patterns. Several boundary conditions which were designed to effectively replace the presence of injector orifices have been tested and it was found that a simple modeling can be possible by mimicking the actual shape of the orifices.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.257-263
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• 2006

Liquid rocket combustion chamber must have high confidence in combustion performance and combustion stability. Expecially, an injector playing a part in the mixing of propellants is an important parameter to determine it. The present study was carried out in the viewpoint of combustion stability to evaluate the combustion stability characteristics of Coaxial Swirl Injector, using a model similarity method. Besides, in case of baffle applied to improve combustion stability, the effectiveness getting from changing the axial length and the gap of baffle was investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.11
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• pp.1140-1147
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• 2009

Flow analyses have been performed to investigate the uniformity of propellant flow through the fuel and oxidizer manifolds of a full-scaled gas generator for a pump-fed liquid rocket engines. Injectors were simulated as porous medium layers having equivalent pressure drops. The uniformity of propellants has been analyzed for 3 fuel rings and 3 injector head configurations. The mixture ratio distribution at the exit of injectors has been estimated from the mass flow rates of fuel and oxidizer. The best configuration of fuel ring and injection head was selected through these flow analyses.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.31-34
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• 2012

Numerical simulations of the steady and unsteady state were conducted for a coaxial swirl injector with Kerosene fuel. Non-premixed equilibrium model based on chemical equilibrium assumption was used as turbulence-chemistry interaction model. As an equations of state, SRK(Soave-Redlich-Kwong) EOS was applied to deal with the behavior of real fluid in a high pressure condition. Through the steady and unsteady computations, mean values of steady and time-averaged unsteady state were compared on the temperature and OH mass fraction and it was shown that the flame structure of steady state was different to that of time-averaged unsteady state.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.32-39
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• 2018

Supercritical injection behavior of liquid hydrocarbon compounds, which are used as main components of propellant fuel, was analyzed. Decane and Methylcyclohexane (MCH) with different critical points were selected as experimental fluid and Shadowgraphy technique was used. Decane and MCH behave differently in the initial state under the subcritical condition. However, near the critical point, the enthalpy of evaporation became close to 0, so that phase change into supercritical fluid occurred, not vaporization process, and no breakup of both fluids occurred.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.305-308
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• 2005

This paper presents a fabrication of a full-stale combustion chamber of a liquid rocket engine for a ground hot firing test. Engine drawings for manufacturing were prepared after conceptual and detail designs. The combustor is composed of a head and a chamber. SUS316L is used for materials of the head because of the good quality in low temperature. Inner materials of the ablative cooling chamber is silica/phenolic and outer case materials is the SUS316L. Materials of the regenerative cooling chamber are C18200 and SUS316L. After lathe, general milling and MCT machinings, components were finished by electrolytic polishing. A brazing method was applied for bonding the injectors and the injector plate, the regenerative cooling chamber because of structure configurations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.48-58
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• 2006

The spray and combustion characteristics of liquid jet in cross flow with variation of injection angle are numerically studied. Numerical analysis was carried out using KIVA code, which may be used to generate numerical solutions to spray and chemical reactive fluid problem in three space dimensions and modified to be suitable for simulating liquid jet ejected into the cross flow. Wave model and Kelvin- Helmholtz(KH) /Rayleigh-Taylor(RT) hybrid model were used for the purpose of analyzing liquid column, ligament, and the breakup of droplet. Penetration length increases as flow velocity decreases and injection velocity increases. Numerical error increases as inflow velocity increases. The results of flame propagation contour in combustion chamber and local temperature distribution, combustion emissions were obtained.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.869-872
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• 2011

Ignition tests of an oxidizer rich preburner for a staged combustion cycle liquid rocket engine were performed to evaluate combustion performance. Design operation conditions of the tested oxidizer rich preburner are about 60 of OF ratio and 20 MPa of combustion pressure. The entire kerosene and some LOx injected into the mixing head is burned in combustion chamber and the remaining LOx injected through center holes of combustion chamber is vaporized. Full flow ignition method with hypergolic fuel was used. Each propellant was supplied in two stages for soft ignition. Test results, low frequency oscillation was occurred in low flow rate conditions under 45% of design flow rate. Stable ignition in the course of design combustion pressure was able to induce by minimization of low flow rate ignition region to escape low frequency oscillation.