• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.5
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• pp.37-46
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• 2012

The calculation model for heat transfer analysis of rocket engine combustion chamber considering film-cooling has been established. Convective, radiative heat transfers and film-cooling effect in combustion chamber were evaluated using empirical equations especially for rocket engine combustors, and for heat transfer outward from chamber wall general convective and radiative equations were applied. Structural grid has been generated inside chamber wall for FVM calculations, and transient thermal analyses were carried out by time-marching techniques. LOx/kerosene rocket engine with chamber pressure of 50 bar has been analysed, and it is shown that, in that case, the film-cooling less than 4% remarkably contributes to reduce wall temperature, but the effect of the effect of film-cooling more than about 4% is not significantly increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.867-868
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• 2011

Transient Analysis on heat transfer of rocket engine combustion chamber and wall temperature variation was carried out, especially, calculations of LOx/kerosene rocket engine with/without fuel film-cooling were conducted. Convective and radiative heat flux inside combustion chamber wall were calculated by the empirical equations for rocket engine combustion, and conduction of wall interior was calculated by numerical method with 2D axisymmetric grid. In this calculations the transient variations of wall temperature, the location changes of peak temperature and so on affected by film-cooling were analyzed.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.57-64
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• 2011

It has been suggested that turbulent effect should be considered for the study of highly unstable detonation of hydrocarbon fuels, as in the case of pulse detonation engine (PDE). A series of numerical study are carried out to understand the characteristics of the highly unstable detonation by considering viscosity, turbulence model and turbulence-combustion interaction model. Through studies of the different levels of modeling, it is understood that the viscosity and turbulence have negligible effects on low frequency characteristics, but tend to enhance the high frequency characteristics. It is also considered that the turbulence-chemistry interaction model should be taken the influence of the activation energy into account for detonation studies.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.21-24
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• 2010

The cooling channel of the preburner for staged combustion engines was studied. The combustion pressure of the researched preburner is about 210 bar which is very high compared with the engines of the Korean Launch Vechicle and 30 ton class liquid rocket engines developed as a pre-research program. Also, the combustion is an oxygen rich process unlike the gas generators of open cycle kerosene engines. Thus the cooling process is very important to make the preburner stable. Many configurations for the preburner were developed and numerically analyzed. As a result, the pressure loss could be reached below the target.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.1
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• pp.64-72
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• 1997

An analytical study has been performed to investigate the unsteady ignition characteristics of pulse combustion. In many combustion applications, strain rate of the flow can significantly affect the combustion features; ignition, extinction, and reignition. In the pulse combustion, two jets (hot combustion gases and fresh mixtures) coming from the opposite side of the combustor will collide in the combustor forming a stagnation region where the chemical reaction is suppressed by the strain rate until this becomes below the critical value. In this research, the method of large activation energy asymptotic is adopted with one step irreversible kinetics to examine the ignition response to the periodic variation of the strain rate of flow. The results show the variation of the maximum value of strain rate can determine whether the ignition or extinction occur.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.69-76
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• 2003

For stable combustion and safety of a structure of the propulsion system, a cooling system to the liquid rocket engine should be incorporated. In this study, Eulerian-Lagrangian scheme for two phase combustion, nongray radiation and soot formation effect, and film-wall interaction have been introduced to study the effect of film cooling. After briefly introducing the governing equation, combustion characteristics with change of wall temperature has been investigated by varying such parameters as fuel mass fraction for film cooling, diameter of the fuel droplet, overall mixture fraction of oxygen to fuel. Also, radiative heat flux is compared with the conductive one at the combustor wall.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.636-640
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• 2011

Film cooling technique has been applied to effectively reduce thermal load on liquid rocket combustion chambers by direct injection of a portion of propellant, which flows through the regeneratively cooling channels, into the chamber wall. This study developed a comprehensive model to quantitatively predict the effects of kerosene film cooling on propulsive performance and wall cooling at supercritical pressure conditions, and assessed the predictive capability against hot-firing tests of an actual combustor. The present model is expected to be utilized as a design and analysis tool to meet the conflicting requirements in terms of performance, cooling, pressure loss and weight.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.289-292
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• 2009

Injector dynamics of multi swirl injectors in an annular combustor have been investigated by LES(Large Eddy Simulation) turbulent model with MPI parallel computation technique. The present study employs the LM6000 lean premixed swirl-stabilized annular combustor. Real shape combustor is simulated in order to investigate the detail interaction mechanism among multi-injectors. The strong vortex breakdown occurs at the impinging surface between the adjacent injectors so that the complex and strong oscillatory pressure propagates inside of the combustor. Tangential pressure fluctuation mode was captured by including multi injectors in computational domain.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.1-8
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• 2010

Acoustic tuning of quarter-wave resonator is investigated numerically to suppress combustion instability in liquid rocket engines. A model combustion chamber is adopted. First, basic acoustic characteristics are examined and acoustic damping is pursued by quarter-wave resonators. Next, for frequency tuning of the resonators, thermodynamic properties inside the acoustic resonators are estimated based on the numerical data. Maximum damping capacity is obtained when the resonators are designed to have the optimum length calculated with the properties. But, damping capacity induced by the resonators with the same length is comparable with it.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.36-42
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• 2004

The Properties of material, C18200 which is used for development of high performance liquid rocket engine combustor chamber were obtained by tension tests. The specimen for regenerative combustor was designed by structural analysis using that Properties. After the designed specimen was manufactured by the same manufacturing process of regenerative combustor. the yielding stress and yielding strain were obtained by strength tests. The properties of C18200 was degraded very much after brazing. The estimation of yielding pressure by structural analysis was almost same as that of strength test. The collector Part was yielded and failed previously than that of cooling channel part during strength test.