• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.40 no.3
• /
• pp.315-320
• /
• 2020

Pellets are manufactured using wood by-products. The combustion efficiency of pellets depends on the pellet manufacturing process, the types of materials mixed while manufacturing and the wood pellet stoves themselves. In this study, we developed a multi-layer combustor to be used in a wood pellet stove, for the purpose of reducing environmental pollution and energy waste due to incomplete combustion. The multi-layer combustor was designed to compensate for the shortcomings of existing combustors. A CAD (Computer Aided Design) model was verified using a 3D printer and a prototype was developed. The combustion experiments were conducted on commercial and proposed combustors using pellets of the same brand, manufacturing date, place and specifications. From the experiments, it was found that the proposed combustor produced the lowest carbon monoxide (CO) emission and highest thermal efficiency.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.69-73
• /
• 2009

Combustion test results of 1/2.5-scale thrust chamber for 75tonf-class liquid rocket engine were described. The thrust chamber has chamber pressure of 60 bar, propellant mass flow rate of 89 kg/s, and nozzle expansion ratio of 12. The combustion tests were conducted to verify the combustion performance, the regenerative cooling performance and the durability of thrust chamber at design point condition, and then were performed to confirm the operation and the combustion performance at low combustion pressure condition. All the tests had been successfully executed without the damage of the hardware. These test results present a possibility of hot firing test at low combustion pressure condition, and can be used as fundamental data to predict the combustion performance at design point condition for 75 tonf thrust chamber.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.139-143
• /
• 2007

The overall results of combustion tests performed for a 30 tonf-class full-scale combustion chambers of a liquid rocket engine were described. The combustion chambers have chamber pressure of 53${\sim}$60 bar and propellant mass flow rate of 89 kg/so The combustion chamber is composed of mixing head, SUS baffle, baffle injector, ablative chamber, channel cooling chamber and regenerative cooling chamber. The test results show that the combustion characteristic velocity is in the range of 1673${\sim}$1730 m/sec and the specific impulse of the combustion chamber is in the range of 254${\sim}$263 sec. As the recess number of the injectors increases, the combustion characteristic velocity increases. And as the combustion characteristic velocity increases, the specific impulse of the combustion chamber also increases.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.5
• /
• pp.92-100
• /
• 2010

Combustion stability rating tests of 75-tonf-class thrust chamber for technology demonstration were carried out at a low pressure. Two kinds of mixing heads were used in this study. One of them has injectors of 631 and the other has injectors of 721. Mixing head with injectors of 631 showed a self-oscillation instability at the chamber pressure of 30 bar. Mixing head with injectors of 721 showed that a high frequency combustion stability was maintained under the same pressure and the same mass flow rate. But mixing head with injectors of 721 generated a self-oscillation instability at the chamber pressure of 20 bar and it was found that stability boundary region was changed due to the configuration of a mixing head from these results.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.14 no.5
• /
• pp.8-14
• /
• 2010

For the development of a liquid rocket engine, hot-firing tests of a regeneratively cooled thrust chamber were performed at chamber pressures of approximately 30 and 60 bars. In the paper, pressure fluctuation data, which were obtained from the dynamic pressure transducers installed in propellant manifolds and combustion chamber, were analyzed. Compared to the data at chamber pressure of 60 bar, the results at chamber pressure of 30 bar showed low-frequency oscillations around 150 Hz in the combustion chamber. The low-frequency waves in the combustion chamber were coupled with those in the manifolds. However, the RMS values of the chamber pressure fluctuations at chamber pressure of 30 bar were only 0.8% of the chamber pressures. Thus, it can be inferred that the thrust chamber operates in the stability boundary even at low chamber pressure.

• Nuclear Engineering and Technology
• /
• v.27 no.6
• /
• pp.911-917
• /
• 1995

로듐 자기 기전력형 중성자 계측기는 단위 중성자당 발생되는 전류 신호가 매우 커 계측성이 우수하나 연소율이 빨라 자주 교체해야 하므로 재장전 기간 연장 및 새로운 로듐계측기 구입 등의 문제점이 있다. 75% 연소에 해당하는 제5핵 연료 주기 기간 동안 영광 3, 4호기와 같은 C-E 원자로에 사용되고 있는 로듐 자기 기전력형 중성자 계측기의 연소 거동이 C-E에 의해서 연구되었다. 약 제3핵연료주기까지 분석한C-E의 초창기 연구에서는 중성자 방사화율 개념에 근거하여 약 66%연소시점까지 로듐계측기 연소특성곡선은 선형적임이 밝혀진 바 있다. ［l, 2］ 그 후 C-E의 연구에 의하면 약 75% 연소에 해당하는 제5핵연료 주기까지도 로듐계측기 연소 특성 곡선은 선형적임이 밝혀졌다. 그 결과로 C-E형 원자력발전소에서 사용되는 로듐 노내계측기의 수명을 약 60%연소에서 66%연소 시점까지 연장시킬 수 있게 되었다. ［3］이 정도의 계측기 수명 연장은 약 반년의 원자로 운전 기간에 해당되며 차기 핵연료주기에서 많은 로듐 노내계측기를 계속 사용할 수 있게 한다. 특히 영광 3, 4호기가 12개월 핵연료 주기에서 18개월 핵연료 주기로 재장전 전략을 바꿀 경우 로듐 노내계측기의 수명 이 연장되지 않으면 계측기 교체가 빈번해 질 것으로 사료되어 로듐 수명 연장과 관련된 기술 특히 C-E 및 B&W의 로듐 노내계측기 연소도 특성곡선 불확실도 평가 및 출력 측정 계통 오차 분석 기술을 소개하고자 한다. 영광3, 4호기에서 사용중인 로듐 노내계측기 수명을 현재 연소도 기준 66%내로 한정하고 있는데 C-E 및 B&W의 로듐 노내계측기연소 특성에 관한 연구 내용을 분석한 결과 노내계측기 수명을 연소도가 66%를 초과하는 계측기가 있어도 전체적으로 불확실도가 안전한계를 넘지 않으면 노내상주가 가능한 것으로 평가되었다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.25 no.3
• /
• pp.89-100
• /
• 2021

This paper deals with the construction of a combustion test facility and preliminary tests for hot-firing tests of a methane engine. First, the combustion test facility for a 1 kN-class thrust chamber using liquid oxygen/gas methane as propellants was designed and built. Before hot-firing tests, the cold-flow tests of each propellant line and the ignition tests of torch igniter/afterburner were performed to verify propellant supply stability of the combustion test facility, operation of the control and measurement system, and successful ignition. Finally, a preliminary hot-firing test was conducted to measure the combustion efficiency, heat flux, and combustion stability of a thrust chamber prototype. The constructed combustion test facility will be helpfully used for basic research and development of methane engine thrust chambers.

• 한국연소학회:학술대회논문집
• /
• 2014.11a
• /
• pp.283-284
• /
• 2014

• Journal of the korean Society of Automotive Engineers
• /
• v.15 no.6
• /
• pp.14-22
• /
• 1993

본 글에서는 자동차엔진을 모형화한 정적연소기내의 라디칼 계측기술에 관해 언급하고자 한다. 밀폐연소기내에서 연소반응에 의해 발생된 국소 및 평균 라디칼 강도를 계측하여 순간당량비를 구할 수 있는 관계식을 유도할 수 있으며, 이것을 이용하면 기관에서 발생되는 연소과잉에 의하여 순간당량비를 구하거나, 각종 산업용 버너 등 다양한 연소기에 적용할 수 있을 것이다.

• Journal of the KSME
• /
• v.56 no.9
• /
• pp.54-57
• /
• 2016

로켓연소기는 수백 개의 분사기로 구성된 연소실에서 연소반응이 발생하게 된다. 이때 구조적인 특성으로 난류유동, 밀도, 온도 등의 변화가 매우 불균일한 3차원적인 분포를 가지게 된다. 이러한 불균일한 분포에 의해 발생되는 압력의 시간변화가 연소기의 고유진동수와 일치될 경우 공진이 발생하게 되어 폭발이 발생하게 된다. 이러한 현상을 연소불안정이라 하고 이글에서는 관련된 연구의 동향을 소개하고자 한다.