• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.35-44
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• 2011

Mathematical modelling for liquid rocket engine(LRE) main components were conducted to predict the dynamic characteristics when the LRE operates at the transient condition, which include engine start up, shut down, or thrust control. Propellant feeding system is composed of fuel and oxidizer feeding components except for regenerative cooling channel for the fuel circuit. Components modeling of pump, pipe, orifice, control valve, regenerative cooling channel and injector was serially made. Hydraulic tests of scale down component were made in order to validate modelling components. The mathematical models of engine components were integrated into LRE transient simulation program in concomitant with experimental validation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.186-190
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• 2006

This study was performed to investigate the characteristics of a co-axial swirl injector. Especially to predict the initial liquid sheet thickness and spray cone angle of an outer orifice a concept of effective area was introduced from hydraulic analysis. In addition, the parameters determining the characteristics of a co-axial swirl injector were re-defined around outer orifice. The calculated results-SMD, spray cone angle, and spray thickness agreed well with the test results qualitatively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.157-160
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• 2007

Spray characteristics of an injector employed in liquid rocket engine is investigated by Particle Image Velocimetry and Dual-mode Phase Doppler Anemometry measurements. Instantaneous plane images captured by PIV technique are examined in order to judge a pass-fail criteria of spray injection performance. DPDA technique is also applied in order to measure the velocity and diameter of spray droplets. The eternal objective of this study is to evaluate an injector performance which may be utilized for the design of brand-new ones through the clear understanding of spray characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.61-65
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• 2010

To research and develop a liquid rocket engine injector, it needs empirical studies about the hydrodynamic and spray characteristics such as pressure drop, mixing and atomization. In this study, the design and implementation of lab-scale cold-flow/hot fire test stand which can supply cryogenic propellant and be controlled by time-critical LabVIEW cyclogram logic has been done. In order to visualize the spray of a liquid-centered swirl coaxial injector in cryogenic condition, LN2-GN2 cold-flow test has been done, and combustor assembly and thrust bed for LOX-$GCH_4$ hot-fire test have been fabricated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.49-53
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• 2009

The paper presents the results of the experimental study about flow discharge characteristics of double swirl coaxial injectors for a liquid rocket engine. Flow discharge characteristics of injectors become one of critical design issues for LRE combustion devices. Tap water and liquid oxygen/kerosene were used for ambient and hot firing tests, respectively. A combustion discharge coefficient varies depending on a mixture ratio and a recess ratio, and magnitudes of the variations are different with respect to injector shapes and operating conditions. The variation of a combustion discharge coefficient with a LOx injector is considered to result from flame structure changes due to physical property changes.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.2
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• pp.62-69
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• 2003

Swirl injectors have the advantage of stable combustion, high efficiency, and insensibility to variable O/F ratio. Recess length is the length from outer orifice tip to inner orifice tip. It is the very important variable of performance of swirl type injector Recess length have influence on collision, mixing, spray, and combustion of propellants. This study investigated on the engine performance with the change of recess length through CFD, cold flow test, and combustion test. In result, we could confirm the change of engine performance with the change of recess length. And we found that performance forecast process through CFD, cold flow test is the right process through combustion test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.205-209
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• 2004

The configuration and arrangement of injector in LRE gas generator and combustor have a great impact on combustion process and heat exchange because of affecting atomization, vaporization, mixing and chemical reaction. A relation between injector array and mixing distribution of propellants based on a physical approach was investigated in this study. Programming method of this relation is used to predict mixing distribution of propellants. Simplicity of physical approach and various assumptions make it reduce the accuracy and application of the results of present study. But, this method is very useful to predict the mixing distribution of full scale combustor due to difficulties in cold flow testing.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.619-625
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• 2015

Swirl injectors are widely used for Liquid Rocket Engine(LRE) as fuel injection system and following researches are also being carried out throughout the world. Especially, solving combustion instability problem is essential for every type of LREs. In this study, cold test was carried out for open type swirl injector as a fundamental research to solve combustion instability problem. Pressure fluctuation was applied to the inlet flow coming into the injector and the following response characteristics were observed. The effect of swirl chamber geometry was also studied by changing both swirl chamber length and diameter.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.72-76
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• 2010

To research and develop a high performance injector for LRE, it needs not only cold flow test, but also investigations of combustion performance, optimization of cyclogram and thermo-fluid dynamical characteristics of combustion flow field through hot-fire test. In this study, hot-fire test of LOX-CH4 coaxial swirl injector has been carried out using lab-scale hot fire test stand which can supply and control cryogenic propellant. Ignition and continuous combustion for LOX-$GCH_4$ propellant of 0.19 kg/s total mass flowrate and 2.80 O/F Ratio was achieved through cyclogram optimization. The mean combustion chamber pressure and thrust were measured as approximately 1.43 MPa and 38.7 kgf respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.117-120
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• 2007

This study investigated the spray modeling of the pressure-swirl atomizer installed in liquid rocket engine and the effect of drop distribution function especially. The $X^2$, originally implemented to KIVA, Rosin-Rammler and modified Rosin-Rammler distribution functions were investigated theoretically and compared to each other. Also, they were applied to pressure-swirl atomizer similar to the injector installed in liquid rocket engine to evaluate the feasibility for LRE injector. Among the distribution functions, original Rosin-Rammler distribution function was the most compatible with predicting the spray characteristics of pressure-swirl atomizer installed in liquid rocket engine.