• Title/Summary/Keyword: Combustion velocity

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Case Study on Combustion Stabilization in FASTRAC combustor using Acoustic Cavities (FASTRAC 연소기에서 음향공을 이용한 연소불안정 제어 사례 연구)

  • Kim, Hong-Jip;Kim, Seong-Ku
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.16-23
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    • 2012
  • 3-D linear acoustic analysis has been performed to elucidate damping characteristics of large Helmholtz acoustic cavities in FASTRAC combustor. Acoustic impedance concept has been introduced to quantify combustion stabilization capacity. For a given acoustic cavity, sonic velocity in cavity to achieve an optimal tuning has been determined and satisfactory agreement with the previous results has been obtained. Feasible estimation of sonic velocity in acoustic cavity has been devised. Results show similar trends without significant deviations, which can be used in the procedure of design and verification of acoustic cavity. From the satisfactory results, investigation of other combustors with acoustic cavities which have shown combustion instabilities will be done as future works.

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Combustion Characteristics and Application of Cyclon Combustor

  • Chae, J.O.;Xu, F.Z.;Yu, J.;Moon, S.I.;Kim, K.Y.
    • 한국연소학회:학술대회논문집
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    • 2001.06a
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    • pp.82-89
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    • 2001
  • This paper concerns lean gas cyclone combustion system adopting distributed inlets with different velocity to promote ignition and burnout properties. Detailed temperature measurements have been achieved under different operating conditions and flue gas compositions and NOx have been measured. Experimental results show that cyclone combustor provided increasing combustion stability and reduction NOx emission level to negligible level.

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The rapid synthesis of $MoSi_2$ for high-temperature furnace heating elements

  • Soh, Dea-Wha;Natalya, Korobova
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.38-41
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    • 2001
  • The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The influence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of $MoSi_2$ during SHS might be different and depending on experimental conditions.

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The rapid synthesis of MoSi$_2$ for high-temperature furnace heating elements

  • Soh, Deawha;Korobova, Natalya
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.38-41
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    • 2001
  • The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The inf1uence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of MoSi$_2$ during SHS might be different and depending on experimental conditions.

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Combustion Characteristics of Gas Generator for Liquid Rocket Engine (액체로켓엔진 가스발생기 연소특성)

  • Kim, Seung-Han;Han, Yeoung-Min;Moon, Il-Yoon;Lee, Kwang-Jin;Seol, Woo-Seok;Lee, Chang-Jin;Kim, Seung-Han
    • 한국연소학회:학술대회논문집
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    • 2004.11a
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    • pp.213-216
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    • 2004
  • The results of combustion performance test of fuel-rich gas generator(GG) using LOx and kerosene as propellant at design and off-design point are described. The parameters used in this analysis are the average exit temperature($T_{GG}$) and the characteristic velocity($C^{\ast}$). The average gas temperature at the exit of gas generator is found to be a function of propellant O/F ratio. For the gas generator having residence time of 4msec or more, the effect of flame residence time and combustion chamber pressure on the exit temperature is not significant. The exit characteristic velocity is found to be linearly proportional to the gas temperature at the exit of gas generator.

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Combustion Experiment Measurement Uncertainty for Hybrid Rocket Motor (하이브리드 로켓 모터에 대한 연소 실험 측정 불확도)

  • Kim, Soo-Jong;Moon, Hee-Jang;Kim, Jin-Kon
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.19 no.1
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    • pp.7-14
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    • 2011
  • In this study, the measurement uncertainty of combustion experimental system and experimental parameters for hybrid rocket were evaluated by B type evaluation method. The measurement uncertainty of all experimental parameters was lower than 3%. The highest value of expanded uncertainty was characteristic velocity efficiency with 2.83% and the expanded uncertainty of regression rate which is the design and performance parameter was indicated to 0.03%. These results shown that the reliability of hybrid combustion system was located within allowed limits.

Prediction of Development Process of the Spherical Flame Kernel (구형 화염핵 발달과정의 예측)

  • 한성빈;이성열
    • Transactions of the Korean Society of Automotive Engineers
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    • v.1 no.1
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    • pp.59-65
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    • 1993
  • In a spark ignition engine, in order to make research on flame propagation, attentive concentration should be paid on initial combustion stage about the formation and development of flame. In addition, the initial stage of combustion governs overall combustion period in a spark ignition engine. With the increase of the size of flame kernel, it could reach initial flame stage easily, and the mixture could proceed to the combustion of stabilized state. Therefore, we must study the theoretical calculation of minimum flame kernel radius which effects on the formation and development of kernel. To calculate the minimum flame kernel radius, we must know the thermal conductivity, flame temperature, laminar burning velocity and etc. The thermal conductivity is derived from the molecular kinetic theory, the flame temperature from the chemical reaction equations and the laminar burning velocity from the D.K.Kuehl's formula. In order to estimate the correctness of the theoretically calculated minimum flame kernel radius, the researcheres compared it with the RMaly's experimental values.

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Theoretical Analysis of a Spark Ignition Engine by the Thermodynamic Engine Model

  • Han, Sung Bin
    • Journal of Energy Engineering
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    • v.24 no.3
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    • pp.55-60
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    • 2015
  • Recent engine development has focused mainly on the improvement of engine efficiency and output emissions. The improvements in efficiency are being made by friction reduction, combustion improvement and thermodynamic cycle modification. Computer simulation has been developed to predict the performance of a spark ignition engine. The effects of various cylinder pressure, heat release, flame temperature, unburned gas temperature, flame properties, laminar burning velocity, turbulence burning velocity, etc. were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion model for a spark ignition engine running with isooctane as a fuel and predicting its behavior.

A Study on the Self Flue Gas Recirculating Flow of the Regenerative Low NOx Burner (축열식 저 NOx 연소기의 배기가스 내부 재순환 유동에 대한 연구)

  • Kim, Jong-Gyu;Kang, Min-Wook;Yoon, Young-Bin
    • 한국연소학회:학술대회논문집
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    • 2001.11a
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    • pp.17-26
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    • 2001
  • Self flue gas recirculation flow is an effective method for low NOx emission in the regenerative low NOx burner. The object of this study is to analyze the self flue gas recirculating flow by varying jet velocity of the combustion air. Fuel and air flow rates are fixed and combustion air jet nozzle diameters are 13, 6.5 and 5mm. The stoichiometric line is obtained from the concentration of the fuel using an acetone PLIF technique. It is found that the self flue gas recirculating flow is entrained into that line using a two color PIV technique. As the jet velocity of combustion air is increased, the flue gas entrainment rate into the stoichiometric line is increased. This result suggests that NOx emission can be reduced due to the effects of flue gas which is lowering the flame temperatures.

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Propagation Speed Characteristics of Premixed Methane-Air Flame in a Combustion Chamber with Model of Engine Cylinder (엔진실린더 모형 연소실내의 메탄-공기 예혼합기의 화염전파속도 특성)

  • 전충환
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.2
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    • pp.225-231
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    • 1998
  • Flame propagation speed characteristics of methante-air mixtures were experimentally investigated in combustion chamber modelled engine. Flame propagation process was known as a funtion of equivalence ratio initial pressure and initial temperature. Ion probe and schlieren photograph were applied to measure the local flame speed and flame radius in quiescent mixtures. Pressure was also measured to make sure of the reproducibility and to apply combustion analysis. Burning velocity was calculated from the flame propagation speed and combustion analysis. Flames were developed faster with higher initial pressure and initial temperature but showed maximum propagation speed at equivalence ratio 1.1 regardless of initial pressure and temperature. Local flame speed was maximum values at near midpoint between center and wall.

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