• Title, Summary, Keyword: Field burning

Search Result 104, Processing Time 0.038 seconds

Reactive Fields Analysis of End-Burning Hybrid Combustor Using Tangential Oxidizer Injectors with Various Momentum Ratio (접선형 산화제 주입기의 운동량비에 따른 End-Burning 하이브리드 연소기의 연소유동장 해석)

  • Min, Moon-Ki;Kim, Soo-Jong;Kim, Jin-Kon;Moon, Hee-Jang
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.11 no.2
    • /
    • pp.37-46
    • /
    • 2007
  • In this study, combustion fields of the end-burning hybrid combustor with tangential oxidizer injectors are examined. Momentum ratio of oxidizer is used as a main parameter to analyse the combustion efficiency with temperature, pressure, swirl velocity and mixture fraction field. It was found that as momentum ratio decreases the overall combustion efficiency is enhanced with the pressure field being insensitive to momentum ratio keeping quasi-uniform distribution. Irrespective to the momentum ratio, annular hot region commonly occurred in the upper combustion chamber where this phenomenon was left for a future improvement to be followed.

Emission of Air Pollutants from Agricultural Crop Residues Burning (농업잔재물 소각에 의한 대기오염물질의 배출 특성)

  • Park, Seong-Kyu;Hong, Young-Shil;Kim, Daekeun;Kim, Dong Young;Jang, Young Kee
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.31 no.1
    • /
    • pp.63-71
    • /
    • 2015
  • The gaseous and particulate emissions from agricultural crop residues burning were investigated. The test residues included white soybean stem, pepper stem, apple branch, peach branch, pear branch, grape branch, sesame stem, perilla stem, and barley stem. Particulate emissions were dominated by fine particles (< $0.1{\mu}m$ in size). The highest $PM_{2.5}$ Emission factors were from barley stems (35.2 g/kg), and the lowest from pepper stems (7.9 g/kg). Emission factors for CO, NO, and VOCs were 146~305 g/kg, 4.94~15.02 g/kg, 27.4~353.3 g/kg, respectively. Benzene played an important role in VOCs emissions from biomass burning.

Thermal Stress Anaysis of Burning Plate by Configuration of Outdoor Gas Boiler (야외용 가스보일러의 연소판 형상에 따른 열응력 해석)

  • Lee, Suk Young
    • Journal of Energy Engineering
    • /
    • v.24 no.4
    • /
    • pp.48-54
    • /
    • 2015
  • This study investigates the result of thermal stress analysis on burning plate by classes at outdoor gas boiler. In the analysis results at the steady state, the maximum stress and deformations are 666,8MPa at A type and 0.20476mm at B type respectively. The deformation becomes larger as the field goes on from the center to the outside at burning plate. As there are 8 types in the order of maximum stress and deformation, F and C type have safest among 8 types respectively. Therefore, F type becomes most excellent on strength and safety among 8 types. By using the analysis result of burning plate model at gas boiler, it is possible to design the model applied practically at the safe component parameters of boiler system.

Estimation of Source Contribution for Ambient Particulate Matters in Suwon Area (수원지역 입자상 오염물질의 오염원 기여도의 추정)

  • 이태정;김동술
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.13 no.4
    • /
    • pp.285-296
    • /
    • 1997
  • The suspended particulate matters had been collected on quartz fiber fiters by a cascade impactor having 9 size stages for 4 years (Sep. 1991 to Dec. 1995) in Kyung Hee University-Suwon Campus. Membrane filters were used to collected the particulate matters on each stage. The weight concentration on each stage was obtained by a microbalance and further chemical element levels were determined by an x-ray fluorescence system. Based on these chemical information, our study focused on applying the target transformation factor analysis (TTFA), a receptor model, to identify aerosol sources and to apportion quantitatively their mass contribution. There are total of 63 ambient data sets. Each data set consists of the 8 size-ranged subdata sets characterized by 16 elemental variables. By the results, four to five sources were extracted from each size range and some sources reappeared in other size ranges. Then total of 8 source profiles were statistically generated from all the ranges, such as oil burning source, soil source, field burning source, gasoline related source, coal burning source, marine source, glass related source, and unknown sources. Apportioning aerosol mass to each source was intensively examined by investigating emission inventories near the study area. The results showed that soil particle source was the most significant contributor. However, coal and oil burning sources were the major anthropogenic ones. The study finally proposed some air quality control strategies to achieve the clean air quality in Suwon area.

  • PDF

Numerical Modeling for Turbulent Partially Premixed Flames (난류 부분 예혼합 화염장에 대한 수치 모델링)

  • Kim, Hoo-Joong;Kim, Yomg-Mo;Ahn, Kook-Young
    • 한국연소학회:학술대회논문집
    • /
    • /
    • pp.191-194
    • /
    • 2003
  • The present study is focused on the subgrid scale combustion model in context with a Large Eddy Simulation. In order to deal with detailed chemical kinetic, the level-set method based on a flamelet model is addressed. In this model, the flame front is treated as an interface, represented by an iso-surface of a scalar field G. This iso-surface is convected by the velocity field and its filtered quantities are include the turbulent burning velocity, which is to be modelled. For modelling the turbulent burning velocity, an equation for the length-scale of the sub-filter flame front fluctuations was developed. The formulations and issues for the turbulent premixed and partially premixed flames are addressed in detail.

  • PDF

The effect of Volume Expansion on the Propagation of Wrinkled Laminar Premixed Flame

  • Chung, E.H.;Kwon, Se-Jin
    • 한국연소학회:학술대회논문집
    • /
    • /
    • pp.139-154
    • /
    • 1998
  • Under certain circumstance, premixed turbulent flame can be treated as wrinkled thin laminar flame and its motion in a hydrodynamic flow field has been investigated by employing G-equation. Past studies on G-equation successfully described certain aspects of laminar flame propagation such as effects of stretch on flame speed. In those studies, flames were regarded as a passive interface that does not influence the flow field. The experimental evidences, however, indicate that flow field can be significantly modified by the propagation of flames through the volume expansion of burned gas. In the present study, a new method to be used with G -equation is described to include the effect of volume expansion in the flame dynamics. The effect of volume expansion on the flow field is approximated by Biot-Savart law. The newly developed model is validated by comparison with existing analytical solutions of G -equation to predict flames propagating in hydrodynamic flow field without volume expansion. To further investigate the influence of volume expansion, present method was applied to initially wrinkled or planar flame propagating in an imposed velocity field and the average flame speed was evaluated from the ratio of flame surface area and projected area of unburned stream channel. It was observed that the initial wrinkling of flame cannot sustain itself without velocity disturbance and wrinkled structure decays into planar flame as the flame propagates. The rate of decay of the structure increased with volume expansion. The asymptotic change in the average burning speed occurs only with disturbed velocity field. Because volume expansion acts directly on the velocity field, the average burning speed is affected at all time when its effect is included. With relatively small temperature ratio of 3, the average flame speed increased 10%. The combined effect of volume expansion and flame stretch is also considered and the result implied that the effect of stretch is independent of volume release.

  • PDF

A phase transformation model for burning surface in AP/HTPB propellant combustion (AP추진제의 연소면 형성 및 전파 모델링 연구)

  • Jung, Tae-Yong;Doh, Young-Dae;Yoo, Ji-Chang;Yoh, Jack Jai-Ick
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.38 no.4
    • /
    • pp.363-368
    • /
    • 2010
  • In the solid rocket propellant combustion, the dynamic phase change from solid to liquid to vapor occurs across the melt layer. During the surface burning, liquid and gas phases are mixed in the intermediate zone between the propellant and the flame to form micro scale bubbles. The known thickness of the melt layer is approximately 1 micron at $10^5$ Pa. In this paper, we present a model of the melt layer structure and the dynamic motion of the melt front derived from the classical phase field theory. The model results show that the melt layer grows and propagates uniformly according to exp(-1/$T_s$) with $T_s$ being the propellant surface temperature.

Numerical Analysis of Combustion Field for Different Injection Angle in End-burning Hybrid Combustor (End-burning 하이브리드 연소기 인젝터 분사각에 따른 연소 유동장의 수치적 연구)

  • Yoon, Chang-Jin;Kim, Jin-Kon;Moon, Hee-Jang
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.35 no.12
    • /
    • pp.1108-1114
    • /
    • 2007
  • The effect of oxidizer injection angle on the combustion characteristics of end-burning hybrid combustor is numerically investigated. Besides the previously studied parameter(injector arrangement, port diameter and O/F ratio), three different injection angle are considered: parallel angle to fuel surface(Case 1), +30 degree inclined angle toward the fuel(Case 2) and 30 degree inclined angle toward the nozzle(Case 3). It is found that Case 2 has the best mixing pattern in the upstream area but has the worst combustion efficiency since non negligible amount of unburned fuel is expelled from the nozzle. In contrast, though Case 1 and Case 3 showed relatively low mixing effect than the Case 2, they had high combustion efficiency. The comparison of numerical results between Case 1 and Case 3 demonstrate that no major difference is encountered, however, Case 1 is expected to have the best combustion efficiency due to the low residence time of the Case 3 injector which heads toward the nozzle.