• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.149-152
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• 2008

Effects of chamber configuration on combustion characteristic velocity of full-scale combustion chamber for 30-tonf-class liquid rocket engine were studied. The configurations of combustion chamber are ablative and channel cooling chamber (${\varepsilon}$=3.2) which have detachable mixing head, and single body regenerative cooling chamber which has nozzle expansion ratio of 3.5 and 12, respectively. The combustion chambers have chamber pressure of 53${\sim}$60 bar and propellant mass flow rate of 89 kg/s, and the injectors of all combustion chamber have recess number 1.0 and double-swirl characteristics. The hot firing test results at design point show that the combustion characteristic velocity of the regenerative cooling chamber which has nozzle expansion ratio of 12 is higher than that of other combustion chambers. The reasons for the above result are the increases of combustion pressure and enthalpy of kerosene which is heated due to cooling of the chamber wall before injection into the combustion field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.2
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• pp.2980-3001
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• 1973

Nozzle is a part of sprayer and is consists of several elements; swirl plate, vortexchamber, cap and body. The travelling distance of sprayed particles is important in the wide reach nozzle. The factors to influence the travelling distance of the sprayed particles may be the helical angle of swirl plate, the distance of vortex hamber, the slope and the size of cap hole. The study was conducted to examine the effects of these factors on the travelling distance. The results of this study are summarized as follows; 1) There was higher positive correlation(+0.96) between the maximum travelling distance for which amount of sprayed particles was 5cc/cm min. and centro-position of the travelling distance. 2) There was a higher positive correlation(+0.85) between total discharge of sprayed particles and the centro-position of the travelling distance. 3) Main effects and interaction effects of helical angle, pressure, vortex chamber distance and cap slope were significantly affected the travelling distance of sprayed particles. 4) Main effects of helical angle, pressure and cap slope were especially highly significant to influence the travelling disance. 5) Helical angle, pressure, vortex chamber distance and cap slope influenced spraying forward velocity of dise hole, among which cap slope and pressure of nozzle was the most important factors. 6) Effect of change of helical angle on the travelling distance of sprayed particles, was generally a quadratic, the least value of the distance being showed about $45^{\circ}$ and the largest at about $15^{\circ}\;and\;55^{\circ}$, the decreasing rate of the change between $15^{\circ};and\;25^{\circ}$ was very small. 7) Effect of change of pressure on the travelling distance sprayed particles was generally a linear, the increasing rate of the charge was about 1.68, which was the most effective compared to the change of the other factors. 8) Effect of change of vortex chamber distance on the spraying distance was also generally a linear, the increasing rate being about 0.16, which was the least effective. 9) Effect of change of cap slope on the travelling distance was also generally a linear, the increasing rate was about 0.61 and its effect was about medium.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2284-2291
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• 2006

The present study investigates gas residence time and mixing characteristics for various swirl numbers generated by injection of secondary air into a lab-scale cylindrical combustor. Fine dust particles and butane gas were injected into the test chamber to study the gas residence time and mixing characteristics, respectively. The mixing characteristics were evaluated by standard deviation value of trace gas concentration at different measurement points. The measurement points were located 25 mm above the secondary air injection position. The trace gas concentration was detected by a gas analyzer. The gas residence time was estimated by measuring the temporal pressure difference across a filter media where the particles were captured. The swirl number of 20 for secondary air injection angle of 5$^{\circ}$ gave the best condition: long gas residence time and good mixing performance. Numerical calculations were also carried out to study the physical meanings of the experimental results, which showed good agreement with numerical results.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1178-1184
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• 1999

The in-cylinder flow field of gasoline engine comprises unsteady compressible turbulent flows caused by the intake port, combustion chamber geometry and the change of the spatial shape. Thus the quantitative analysis of the in-cylinder bulk flow plays an important role in the improvement of engine performances and the reduction of exhaust emission. The influences of tumble intensifying valve (TIV) and swirl intensifying valve (SIV), and various intake-flow conditions are compared with the tumble ratio obtained by the measured results of the in-cylinder gas flow. In order to obtain the quantitative analysis of the in-cylinder gas flows of gasoline engine this investigation applied the particle tracking method to the analysis of gas flow characteristics. Various intake conditions such as tumble and swirl intensifying valve, the deactivated condition of one valve among two intake valves, and the other factors of gas flow are considered.

• Journal of the Korean Society of Combustion
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• v.8 no.1
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• pp.25-35
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• 2003

The objective of this research is to determine generally applicable design principles for the development of internally staged combustion devices. Utilizing a triple annulus combustor, the detailed combustion characteristics are studied. For this triple air staged combustor, the angular momentum weighted by it#s swirl number and air distribution ratio was observed to be the critical criteria of NOx emission. An internal recirculation zone which develops on the centerline of the flame immediately downstream of the burner entraps the fuel into a fuel rich eddy. Then sufficient heat must be transferred from the flame via radiation to the chamber heat transfer surfaces, such that the peak flame temperatures are suppressed when the second air is introduced. It is experimentally found out that the total NOx emission level in this type of burner is below 50ppm(3% Ref. O2) at optimum operating conditions.

• 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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.247-250
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• 2005

In the case of appling a unielement injector developed for a full scale liquid rocket combustor, a operating condition or configuration of the injector is changed by combustion pressure, arrangement and injector quantity of a full scale liquid rocket combustor. In order to verify application, swirl coaxial injectors propelled by jet-A1 and liquid oxygen are tested at different conditions of a combustion pressure, a flowrate and an injector length. As a test result, the application of the present swirl coaxial injectors is excellent because an efficiency of a characteristic velocity is increased at the each test condition beyond that variation of dynamic pressure intensity is small.

• 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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.42-46
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• 2009

For understanding of high performance liquid rocket engine operating at high pressure, dynamic characteristics of liquid oxygen in a swirl injector operating at supercritical conditions has been numerically investigated. Turbulent numerical model is based on large eddy simulation and contains full conservation laws including Soave modification of Redlich-Kwong equation of state and Chung's model. Preconditioning method is applied to get an effective convergence rate. Numerical analysis results are compared with the one that ideal equation of state applied to. Differences of thermodynamic properties and mixing dynamics are investigated at liquid phase area inside injector and combustion chamber.