• Title/Summary/Keyword: combustion characteristic

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Effect of Chamber Configuration on Combustion Characteristic Velocity of Full-scale Combustion Chamber (실물형 연소기의 형상에 따른 연소특성속도 비교)

  • Kim, Jong-Gyu;Han, Yeoung-Min;Ahn, Kyu-Bok;Kim, Mun-Ki;Seo, Seong-Hyeon;Choi, Hwan-Seok
    • 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.

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Hot- Fire Injector Test for Determination of Combustion Stability Boundaries Using Model Chamber

  • Sohn Chae Hoon;Seol Woo-Seok;Shibanov Alexander A.;Pikalov Valery P.
    • Journal of Mechanical Science and Technology
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    • v.19 no.9
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    • pp.1821-1832
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    • 2005
  • This study realizes the conceptual method to predict combustion instability in actual full-scale combustion chamber of rocket engines by experimental tests with model (sub-scale) chamber. The model chamber was designed based on the methodologies proposed in the previous work regarding geometrical dimensions and operating conditions, and hot-fire test procedures were followed to obtain stability boundaries. From the experimental tests, two instability regions are presented by the parameters of combustion-chamber pressure and mixture (oxidizer/fuel) ratio, which are customary for combustor designers. It is found that instability characteristics in the chamber with the adopted jet injectors can be explained by the correlation between the characteristic burning or mixing time and the characteristic acoustic time: In each instability region, dynamic behaviors of flames are investigated to verify the hydrodynamically-derived characteristic lengths of the jet injectors. Large-amplitude pressure oscillation observed in upper instability region is found to be generated by lifted-off flames.

Performance Prediction of Combustion Chamber for 75 ton LRE through Firing Tests at Low Pressure (75톤급 액체로켓엔진 연소기 저압시험을 통한 연소성능 예측)

  • Han, Yeoung-Min;Kim, Jong-Gyu;Lee, Kwang-Jin;Lim, Byoung-Jik;Seo, Seong-Hyeon;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.66-70
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    • 2010
  • The performance of 75 ton liquid rocket engine combustion chamber for a space launch vehicle was predicted through firing tests at low pressure. In low pressure tests of 75 ton LRE combustor chamber, the combustion characteristic velocity of 1750 m/sec and the specific impulse of 240 sec were obtained which are higher than the low pressure performance of 30ton combustion chamber. The combustion characteristic velocity of 1770 m/sec and the specific impulse of 278 sec at design point for 75 ton LRE combustion chamber were predicted by using the low/high pressure performance correlation of 30ton LRE combustion chamber.

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Understanding and Engineering Meaning of Meso-Scale Combustion Phenomena (메소-스케일 연소 현상의 공학적 의미와 이해)

  • Kim, Nam Il
    • 한국연소학회:학술대회논문집
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    • 2015.12a
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    • pp.287-289
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    • 2015
  • Meso-scale combustion is defined as combustion phenomena within limited characteristic length scales that are comparable with the laminar flame length scales. In the laminar flame theory, four representative length scales have been involved; i.e., a reaction layer thickness, a thermal layer thickness, a quenching distance, and a Markstein length. When the effects of these length scales on the flame characteristics are understood, the laminar flame theories can be clarified. Therefore, a study on the meso-scale combustion phenomena should not be thought as just a specific phenomena occurring in an exceptional combustion condition. Instead, all combustion phenomena within meso-scale spaces need to be explained by our knowledge. During this challenge, our understanding on laminar flame structures can be extended. Considering that most turbulent combustion phenomena in engineering application are still have local laminar flame structures, studies on laminar flame structures need to be re-visited especially in academic aspects.

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Effect of Gasoline-premixing on Combustion and Exhaust Emissions Characteristics in Compression Ignition Engines (압축착화 엔진에서 가솔린 예혼합이 연소 및 배기 특성에 미치는 영향)

  • Cha, June-Pyo;Kwon, Seok-Joo;Heo, Jeong-Yun;Lee, Chang-Sik;Park, Sung-Wook
    • Journal of the Korean Society of Combustion
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    • v.15 no.4
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    • pp.53-57
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    • 2010
  • The purpose of the present work is to investigate the effect of gasoline-premixing on a combustion and emissions characteristics in a compression ignition engine. For studying combustion characteristics, a combustion pressure and rate of heat release (ROHR) were measured using a single-cylinder DI compression ignition engine with a common-rail injection system and premixed fuel injection system. In addition, exhaust emissions characteristics were studied using emission analyzers and smoke meter. The experimental results showed that the case of gasoline-premixing had longer ignition delay and lower combustion pressure compared to the cases of diesel direct injection. Furthermore, premixed gasoline-air mixture reduced NOx emissions due to low peak of ROHR.

A Study about an Operating Characteristic of Hydrogen Burner by Using Catalytic Combustion (촉매연소를 이용한 수소버너의 작동 특성에 관한 연구)

  • Kim, Tae-Young;Park, Chang-Kwon;Oh, Byeong-Soo
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.1
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    • pp.1-9
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    • 2008
  • Human has faced in lack of fossil fuel and environmental crisis because of high population growth and development of industry. Hydrogen, unlimited amount and clean resource from water electrolysis, is remarkably known as the solution of recent energy crisis. One of the special characteristics of hydrogen is that a little amount of catalytic such as platinum and palladium makes nonflammable combustion, in other words catalyst combustion. Catalytic combustion fueled by hydrogen is environmentally friendly. This paper considers some comparisons of characteristic of catalytic combustion between a single layer of platinum catalyst, double layer of platinum and nickel catalysts and mixture of platinum and nickel catalysts. Some experiments of temperature distribution at different positions and characteristic of combustion in low temperature region were done in order to find an applicable possibility as a house-cooking burner.

Combustion Performance Results of Combustion Chamber for 30ton-f Class Liquid Rocket Engine (30톤급 액체로켓엔진 연소기 연소시험 성능결과)

  • Han, Yeoung-Min;Kim, Jong-Gyu;Lee, Kwang-Jin;Seo, Seong-Hyeon;Lim, Byoung-Jik;Ahn, Kyu-Bok;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.139-143
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    • 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.

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A Study on Design and Combustion Characteristic of a $H_2O_2$/Kerosene Uni-Injector Rocket Engine (과산화수소/케로신 단일 인젝터 설계 및 혼합비에 따른 연소특성)

  • Kim, Bo-Yeon;Lee, Yang-Suk;Kim, Geun-Chul;Ko, Yung-Sung;Kim, Yoo;Kim, Sun-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.81-84
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    • 2010
  • In this study, a coaxial swirl injector using hydrogen peroxide and kerosene was designed and combustion performance tests were performed to evaluate combustion characteristic according to mixture ratio. Spray characteristic of the injector was verified by cold flow test and combustion performances according to mixture ratio were evaluated by the characteristic exhaust velocity. Test results showed that the combustion efficiency at the design condition was about 95% and the pressure fluctuation was very small.

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Combustion Characteristics of Blended Coals with Bituminous and Sub-bituminous in Oxy-fuel Combustion Conditions (순산소연소 조건에서 역청탄과 아역청탄 혼탄의 연소특성)

  • Sung, Yon-Mo;Moon, Cheor-Eon;Ahn, Seong-Yool;Kim, Seung-Il;Seo, Sang-Il;Kim, Tae-Hyung;Jeong, Ji-Hwan;Choi, Gyung-Min;Kim, Duck-Jool
    • Journal of the Korean Society of Combustion
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    • v.16 no.1
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    • pp.22-29
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    • 2011
  • This paper focuses on the combustion characteristics of blended coals with bituminous and sub-bituminous coals under air and oxy-fuel combustion conditions. The effects of oxygen concentration and blending ratio on the combustion characteristics were experimentally investigated using a thermogravimetric analyser (TGA). Characteristic temperatures including ignition, burnout temperature and activation energy were determined from TG and DTG combustion profiles. As oxygen concentration increased and the presence of sub-bituminous coal, characteristic temperatures and activation energy decreased. The ignitability, reactivity and kinetics have all been greatly improved under oxy-fuel combustion conditions. Based on this, co-firing with bituminous and sub-bituminous coals under oxy-fuel combustion conditions may be suggested as an alternative method to the fuel flexibility and cost-effective power production with carbon capture and sequestration.

Mechanisms of Oblique Shock-Induced Combustion Instability

  • Choi, Jeong-Yeol;Jeung, In-Seuck
    • Journal of the Korean Society of Combustion
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    • v.7 no.1
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    • pp.23-30
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    • 2002
  • Instability of oblique detonation waves (ODW) at off-attaching condition was investigated through a series of numerical simulations. Two-dimensional wedge of finite length was considered in $H_2/O_2/N_2$ mixtures at superdetonative condition. Numerical simulation was carried out with a compressible fluid dynamics code and a detailed hydrogen-oxygen combustion mechanism. Present result reveals that there is a chemical kinetic limit of the ODW detachment, in addition to the theoretical limit predicted by Rankine-Hugoniot theory with equilibrium chemistry. Result also presents that ODW still attaches at a wedge as an oblique shock-induced flame showing periodically unstable motion, if the Rankine-Hugoniot limit of detachment is satisfied but the chemical kinetic limit is not. Mechanism of the periodic instability is considered as interactions of shock and reaction waves coupled with chemical kinetic effects. From the investigation of characteristic chemical time, condition of the periodic instability is identified as follows; at the detaching condition of the Rankine-Hugoniot theory, (1) flow residence time is smaller than the chemical characteristic time, behind the detached shock wave with heat addition, (2) flow residence time should be greater than the chemical characteristic time, behind an oblique shock wave without heat addition.

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