• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.38-44
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• 2000

In general liquid rocket nozzles are protected from hot combustion gas by regenerative cooling techniques. But due to the complexity of the cooling system, it causes increase of system cost and frequently source of the system malfunction. Recently, instead of regenerative cooing, ablative material are used to protect combustion chamber wall and nozzle. To determine the nozzle material erosion rate and erosion shape, more than 500 hot fire test were performed by using 100 lb thrust experimental liquid rocket. Test variable were propellant feed sequence, injector, position of igniter and liquid oxygen supply temperature.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.359-364
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• 2003

Heat regenerator occupied by regenerative materials improves thermal efficiency of regenerative combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of regenerator with spherical particles, were numerically analyzed to evaluate the heat transfer and pressure losses and to suggest the parameter for designing heat regenerator. It is confirmed that the computational results, such as air preheat temperature, exhausted gases outlet temperature, and pressure losses, agreed well with the experimental data conducted from Chugairo. The thermal flow in heat regenerator varies with porosity, configuration of regenerator and diameter of regenerative particle. Assuming a given exhaust gases temperature at the regenerator outlet, the regenerator length need to be linearly increased with inlet Reynolds number of exhaust gases. It is considered that inlet Reynolds number of exhaust gases should be introduced as a regenerator design parameter.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.53-56
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• 2003

This paper describes the general design procedure of cooling system for liquid rocket engine(LRE). From this design logic, cooling channels are designed and fabricated. The measured heat flux from firing test is similar to the heat flux predicted by design logic. Therefore, the proposed design procedure of cooling channel can be applied to real LRE system. Also the result of firing test indicates that combustion pressure and mixture ratio have an influence on the heat flux to be produced in combustion chamber.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.242-247
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• 2004

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swirl flow (DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microrstructure using thermophoretic sampling particle diagnostic (TSPD) as TEM were carried out. The NOx, $CO_2$, $O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.573-578
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• 2003

본 논문은 산업체에서 발생하는 휘발성 유기물질을 연소하는 직접연소기술에 선회연소 개념을 접목하여 개발된 Cyclonic recuperative thermal oxidation system의 연소성능 실험 결과이다. 기존의 recuperative system의 열효율이 75%로 regenerative thermal oxidation보다 낮아 운전비가 많이 소요되는 단점을 극복하기 위해 기존의 연소실에 cyclone 연소시스템을 적용하여 고효율화 시키고자 하는 것이 핵심이다.(중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.313-317
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• 2005

The facility improvement for hot firing test of combustion chamber having thrust of 30-tonf class and chamber pressure of 60bara were performed at ReTF in KARI. The KSR-III main engine having combustion pressure of 13bara and thrust of 12.5tonf had been successfully tested in this facility. To increase the capability of the facility, the feeding and the trust measurement system have been modified. The modification of the feeding system plays also a role of ensuring the stability of propellant supply and two step ignition sequence of combustion chamber. The one-axis thrust measurement system of up to 60tons has been newly manufactured and installed in test stand and the water/kerosene supply lines with high pressure vessel of $4m^3$ and gas nitrogen vessel of $10m^3$ have been designed for regenerative cooling system. The results of cold flow test show that this facility has been successfully improved to satisfy the requirement for hot firing test of high performance combustor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1412-1419
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• 2003

Heat regenerator occupied by regenerative materials improves thermal efficiency of combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of regenerator with spherical particles, was numerically analyzed to evaluate the heat transfer and pressure losses and to derive the design parameter for heat regenerator. It is confirmed that the computational results, such as air preheat temperature, exhausted gases outlet temperature, and pressure losses, agreed well with the experimental data. The thermal flow in heat regenerator varies with porosity, configuration of regenerator and diameter of regenerative particle. As the gas velocity increases with decreasing the cross-sectional area of the regenerator, the heat transfer between gas and particle enhances and pressure losses decrease. As particle diameter decreases, the air is preheated higher and the exhaust gases are cooled lower with the increase of pressure losses. Assuming a given exhaust gases temperature at the regenerator outlet, the regenerator need to be linearly lengthened with inlet Reynolds number of exhaust gases, which is defined as a regenerator design parameter.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.3
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• pp.1-9
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• 2004

We conducted the firing test with the regenerative cooling LRE and calculated the heat flux from measured coolant temperature, that was compared with the heat flux predicted by previously developed numerical analysis method. The difference between the measured heat flux and the numerical calculation value was within nine percents. Therefore, developed numerical analysis method can be applied to the design/fabrication of a real LRE system. and, it was investigated that combustion pressure and mixture ratio have an Influence on the heat flux with a constant relation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.232-235
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• 2017

Scramjet combustor materials are exposed at ultra high temperature over 2000K and severe erosion environment. Inconel alloys are usually applied for combustor material however its mechanical properties are decreased beyond temperature of 1000K so that is impossible for long term operation and reuse. In this study, fiber reinforced ceramic material was used as scramjet combustor material and its feasibility studied. To increase combustion efficiency, regenerative combustor system developed and channel fabrication in composite material also studied.

• Journal of Energy Engineering
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• v.12 no.1
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• pp.35-41
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• 2003

Heat regenerator occupied by regenerative materials improves thermal efficiency of regenerative combustion system through the recovery of heat of exhaust gaset. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of heat regenerator with spherical particles, was numerically simulated to evaluate the heat transfer and pressure drop and thereby to suggest the parameter for designing heat regenerator. It takes about 7 hours for the steady state of the flow field in regenerator, in which heat absorption of regenerative particle is concurrent with the same magnitude of heat desorption. The regenerative particle experiences small temperature fluctuation below 10 K during the reversing process. The performance of thermal flow in heat regenerator varies with inlet velocity of exhaust gas and air, configuration of regenerator (cross-sectional area and length) and diameter of regenerative particle. As the gas velocity increases, the heat transfer between gas and particle enhances and with the increase the pressure losses. As particle diameter decreases, the air is preheated higher and the exhaust gases are cooled more with the increase of pressure losses.