• 한국연소학회:학술대회논문집
• /
• 2007.05a
• /
• pp.31-36
• /
• 2007

The supersonic combustion experiments are carried out using T3 free-piston shock tunnel. Hydrogen Fuel is injected in the cavity parallel with air(or nitrogen fuel) flow. The equivalence ratios in this study are 0.132 and 0.447. Experimental measurements use OH-PLIF near the cavity and pressures in the combustor. For parallel fuel injection case, direct fuel add into cavity leads to increase of cavity pressure. And Flame exists just near the bottom wall for low equivalent ratio. There is no flame in the cavity because of no mixing in it. Compared to the inclined fuel injection, ignition delay length is longer for low equivalence ratio in both case. OH distribution is not a single line but a repeatable fluctuation flame structure by turbulence. Pressure distributions have nothing to do with the fuel injection position.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.229-232
• /
• 2002

For the purpose of Thermal Protection Material design problem, a numerical analysis of axisymmetric high temperature supersonic impinging jet flows of exhaust gas from combustor on curved surfaces has been accomplished. A modifed CSCM Upwind Navier-Stokes method which is able to cure the carbuncle Phenomena has been developed to study strong shock wave structure and thermodynamic wall properties such as pressure and heat transfer rate on various curved surfaces. The results show that the maximum heat transfer rate which is the most important parameter affecting thermo-chemical surface ablation on the plate did not occur at the center of jet impingement, but rather on a circle slightly away from the center of impingement and the shear stress distribution alone the wall is similar to the wall heat transfer late distribution.

• 한국전산유체공학회:학술대회논문집
• /
• 2002.05a
• /
• pp.17-22
• /
• 2002

This paper describes numerical research on transverse jet behind rearward-facing step in turbulent supersonic flowfields without chemical reaction. The purpose of transverse jet behind rearward-facing step is to improve mixing of the fuel in the combustor. Two-dimensional unsteady flowfields generated by slot injection into supersonic flow are numerically simulated by integration of Navier-Stokes equation. Final-scale turbulence effects are modeled with two-equation $\kappa-\epsilon$ model. Numerical methods are modeled high-order upwind TVDschemes. A total of 4 cases are computed, comprising slot momentum flux ratios at four step heights downstream of the step. These numerical results are represented periodic phenomenon in unsteady flowfields.

• 한국전산유체공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.245-248
• /
• 2005

SCRamjet is the key technology for hypersonic flight over mach number 6. It is characterized by very short residence time in combustor because its internal flow is supersonic. In this short time, the whole process of combustion must be done. Especially numerical study of combustor is important because air-fuel mixing rate influences the performance of combustor. Various methods of air-fuel mixing enhancement are proposed. Among these, cavity injection method is selected to study in this paper. The numerical study is conducted with the variation of the cavity length at the fixed height of unit and jet injection on the downstream of cavity.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.419-422
• /
• 2010

An unsteady numerical combustion analysis was performed to investigate the combustion characteristics of A Dual Combustion Ramjet(DCR) engine using a gas generator. According to a variance of the equivalence ratio of the gas generator, the flow pattern in the combustor was analyzed. A typical acoustic frequency in the combustor was observed by detail analysis of pressure fluctuation at each location of the combustor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.294-296
• /
• 2017

In this study heat transfer characteristics of kerosene at supercritical condition was predicted. And a sample heat transfer calculation was performed using this result. The prediction was done by assuming kerosene as a mixture of a number of pure substances, and combining the thermodynamic properties of them, using NIST SUPERTRAPP. A regeneratively cooled supersonic combustor will be desinged using the resultant thermophysical property data of supercritical kerosene. Comparing with the combustion test results of the regenerative cooling combustor, the predicted thermophysical property data will be verified.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.3 no.4
• /
• pp.51-57
• /
• 1999

Temperature and velocity controlling of air at inlet position of Ramjet combustor is important under Ramjet engine grounding-test condition since temperature of inlet air increases due to compression process by supersonic flow at inlet position of Ramjet combustor. In this study, Vitiated Air Heater methodology was used to control temperature of air that is inducted into Ramjet combustor. Temperature and velocity of air at Vitiated air heater exit, which is inducted into Ramjet combustor, were measured to evaluate Vitiated air heater system developed in this study. It is shown that temperature and velocity of inducted air can be well controlled using Vitiated air heater system developed in this study, and we could make a Vitiated Air which is almost same with real air.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.3
• /
• pp.258-263
• /
• 2008

Performance of injector equiped with screw type swirler which is suitable for supersonic cruise engine combustor was investigated using theoretical, numerical, and experimental methods. Based on discharge coefficient and spray angle which represent the performance of injectors, the geometrical parameters which affect these performance parameters were defined, control group injectors were designed, and variation of performance parameters according to the geometrical parameters were examined. Within the defined range, measured value of performance of injectors was smaller than result of theoretical prediction, and prediction result from numerical simulation using VOF method agreed with the result of experiments very well. The viscous barrier was not observed, and minimum discharge coefficient and maximum spray angle, 0.05 and 104 respectively, was obtained for this type of injector.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.12 no.1
• /
• pp.57-63
• /
• 2008

In combustor of SCRamjet of air-breathing engine type, the flow duration time is very short because of the supersonic air flow. In this short duration, the whole process of combustion should be done, so it is very important to study supersonic combustion technologies. In this study, we focus fuel-air mixing enhancement method using cavity and conducted 3-dimensional Navier-Stokes computational analysis. Cavity height is fixed by 10mm, length is changed from 0 to 40mm. There is a supersonic jet injection downstream of the cavity and the hole size is 1mm. As a result, the higher ratio of cavity length/height is, the higher value of vorticity gets. The increased area of vorticity expands to upper and sidewise combustor. However, the stagnation pressure loss which generates thrust loss becomes higher when the vorticity is higher. Considering these result, we can conclude that optimized design which considers the highest mixing performance and the least stagnation pressure loss is needed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.330-335
• /
• 2017

Recently many studies have been made for the development of propulsion system with wide range flight from supersonic to hypersonic. Dual Mode scramjet engine as a hybrid cycle with advantage of ramjet and scramjet has one combustor. It works under the ramjet mode (subsonic combustion) and scramjet mode (supersonic combustion) respectively. In this study, Experimental results of hot firing tests of dual scramjet engine designed on the condition of Mach 3.5~6 as a flight Mach number are discussed. The tests were carried out on a ground test bench under free stream condition of Mach 6 at 27.6km altitude. In the tests, the adopted design and technological solutions were verified and efficient operation of the dual mode ramjet engine with Kerosene combustion during 5 seconds was demonstrated.