• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.4
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• pp.137-144
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• 2006

The basic data obtained in this research for single element performance were directly applied to the design of injector head(7 elements). Designed performance of the 7-element Swirl Coaxial injector was $245kg_f$ sea level thrust with 20bar combustion chamber pressure. Numerical analysis were performed to obtain the change of spray pattern for the design of injector head, and we confirmed the feasibility and application of those results. Hot tests were performed for the multi-element injector to compare with the performance of the single element injector and those can be applied to the design of scaled liquid rocket engine. The basic data obtained in this research can be directly applied to the real liquid rocket injector design.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.47-53
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• 2015

Design parameters required for Methane/oxygen bipropellant small-rocket-engine were derived through a theoretical performance analysis. The theoretical performance of the rocket engine was analyzed by using CEA and optimal propellant mixture ratio, characteristic length, and optimal expansion ratio were calculated by assuming chemical equilibrium. A coaxial-type swirl injector was chosen because of its outstanding atomization performance and high combustion efficiency compared to other types of injector and also a bell nozzle with 80% of its full length was designed. The rocket engine configuration with 1.72 MPa of chamber pressure, 0.18 kg/s in total propellant mass flow, and O/F ratio of 2.7 was proposed as a ground-firing test model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.224-228
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• 2005

Dynamic control tests for Backhole as a dynamic damper were performed. For the forced oscillation generated by pressure drop in the feed line and internal wave analysis of swirl injector, hydrodynamic pulsator and 1D visualization model injector was produced, respectively We focus on effect of Backhole as a dynamic damper instead of a acoustic one. So, the breakup length and film thickness of liquid sheet on the steady state and the forced oscillation state have been measured and compared.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.115-118
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• 2008

Many theoretical and experimental studies have been conducted to investigate elements of the hydrodynamic process, such as variations in liquid film thickness or air core diameter. From these studies, some theoretical relationships have been established through an approximated analytical solution of flow hydrodynamics in a swirl nozzle. However, experimental studies on elements such as internal flow have not produced conclusive results. In this study, the variations and stability of the internal flow were examined by visualizing the air core and measuring the liquid film thickness.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.6
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• pp.30-37
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• 2008

Many theoretical and experimental studies have been conducted to investigate elements of swirl injector hydrodynamics, such as variations in liquid film thickness or air core diameter. From these studies, some theoretical relationships have been established through an approximate analytical solution of flow hydrodynamics in a swirl nozzle. However, experimental studies on elements such as the stability of internal flow have not produced conclusive results. In this study, the stability of the internal flow under tangential entry conditions was examined by visualizing the formation of the air core in the swirl chamber and measuring the liquid film thickness in the orifice.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.97-101
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• 2007

The spray characteristics of the oxidizer-rich preburner are investigated. From the PDPA measurement, droplet SMD of $210{\mu}m$ and droplet axial velocity of 38 m/s are measured at 100 mm distance from the nozzle tip on the fuel pressure of $25kgf/cm^2$ and oxidizer pressure of $10kgf/cm^2$. The droplet velocity is decreased with the axial distance and the oxidizer spray makes dominant effect on the combined spray characteristics of the oxidizer-rich preburner injector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.81-84
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• 2010

In this study, a coaxial swirl injector using hydrogen peroxide and kerosene was designed and combustion performance tests were performed to evaluate combustion characteristic according to mixture ratio. Spray characteristic of the injector was verified by cold flow test and combustion performances according to mixture ratio were evaluated by the characteristic exhaust velocity. Test results showed that the combustion efficiency at the design condition was about 95% and the pressure fluctuation was very small.

• Journal of ILASS-Korea
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• v.11 no.3
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• pp.147-154
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• 2006

A specially designed injector using electric conductivity was used to measure the liquid film thickness accurately. The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement. The variation of air core and stability are examined through the visualization of the formation of air core in swirl chamber and the variation of liquid film thickness by the time.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.70-77
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• 2006

A specially designed in;ector using electric conductivity was used to measure the liquid film thickness exactly, The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The variation of internal flow and stability are examined through the variation of liquid film thickness by the time. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.82-85
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• 2009

In the development of Liquid Rocket Engine(LRE) systems, it is essential to understand the spray characteristics which influence mainly the performance and the stability of combustion. The injectors for this study have a recessed Liquid-swirl/Gas-centered jet coaxial type. For the similarity with actual conditions, the experimental conditions are calculated by using the momentum ratio as a matching parameter, and the stimulants of fuel and oxidizer are gaseous nitrogen and water respectively. The spray fields were measured by means of a photographic technique. Moreover, an effect of the momentum ratio has been investigated.