• Title/Summary/Keyword: 연료분포

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Combustion Characteristics of a Double-cone Partial Premixed Nozzle with Various Fuel hole Patterns (이중 콘형 부분 예혼합 GT 노즐의 연료 분사구 형상 변화에 대한 연소특성)

  • Kim, Han Seok;Cho, Ju Hyeong;Kim, Min Kuk;Hwang, Jeongjae;Lee, Won June
    • Journal of the Korean Institute of Gas
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    • v.24 no.4
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    • pp.25-31
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    • 2020
  • Experimental investigations were conducted to examine the combustion characteristics of a swirl-stabilized double cone premixed burner nozzle used for industrial gas turbines for power generation. Several variants with different fuel injection patterns are tested to compare the combustion characteristics such as NOx and CO emissions, stability, and wall temperature distributions. Main results show that NOx emissions and stability are decreased either when the fuel hole diameter is decreased with the same number of fuel holes, or when the number of fuel holes is reduced with the same total area of fuel holes, both of which are due to a higher penetration of fuel into the air stream. Not only is NOx reduced but also stability is enhanced when the fuel hole diameter varies in an alternating manner with the same total area of fuel holes, showing that NOx reduction is due to a higher penetration of mean fuel injection path while stability enhancement is due to a lowered penetration of minimum fuel injection path.

Performance Analysis of PEMFC Using Computational Flow Dynamics (CFD) (전산유체역학 (CFD)을 이용한 PEMFC의 성능분석)

  • Kim, Sunhoe
    • Journal of Digital Convergence
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    • v.11 no.8
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    • pp.199-204
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    • 2013
  • Computational fluid dynamics (CFD) is used to reduce number of experiments. The CFD tools are widely used for engine design and flow pattern analysis to reduce experiments. In this study the performance of a PEMFC single cell was analyzed by using STAR-CD, product of CD-ADAPCO. The effect of cell design and flow pattern on the performance of a PEMFC was analyzed with the 3-D simulation. As a result the performance of rectangular cell was the higher than that of square cell, while the flow direction scarcely affected on the performance of a PEMFC. Also the current density according to different excess ratio of air flow rate was compared and analyzed. The difference between maximum and minimum current density of flip-flow was lower than that of co-flow.

A Study on the Effect of Coal Properties on the Electrochemical Reactions in the Direct Carbon Fuel Cell System (석탄 물성에 따른 직접탄소 연료전지의 전기화학 반응 특성 연구)

  • Ahn, Seong-Yool;Eom, Seong-Yong;Rhie, Young-Hoon;Moon, Cheor-Eon;Sung, Yon-Mo;Choi, Gyung-Min;Kim, Duck-Jool
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.10
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    • pp.1033-1041
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    • 2012
  • Performance evaluation of a direct carbon fuel cell (DCFC) was conducted according to coals and a graphite particle. Several fuel properties such as thermal reactivity, textural structure, gas adsorption characteristic, and functional groups on the surface of fuels were investigated and their effects on electrochemistry were discussed. The strong carbon structure inside of fuels led the rapid potential decreasing in high current density region, because it caused small surface area and low pore volume. The functional groups on the surface were related to the low current density region. The maximum current density and power density of fuels were affected by the total carbon content in fuels. The effect of operating conditions such as stirring rate and operating temperature was investigated in this study.

Simulation on the gas fueling for the base operation of the KSTAR tokamak (KSTAR 토카막 기본운전을 위한 연료주입 모의실험)

  • In, S.R.;Kim, T.S.;Jeong, S.H.
    • Journal of the Korean Vacuum Society
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    • v.16 no.6
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    • pp.489-495
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    • 2007
  • The assembly of the main system of the KSTAR tokamak has been recently completed, and the preparation for the 1st plasma and test operations is progressed. The fueling system established for these purposes uses only one port placed at the opposite side of the pumping duct, and has a difficulty of attaining a uniform and fast supply of fuel particles to the plasma. At the base operation stage after finishing the test operation, the fueling system must be improved to provide a uniform fueling and a feed-back control in accordance with a high-density tokamak plasma maintained for a long period. As a part for understanding the points to be improved in the fueling system, a Monte Carlo simulation on the gas fueling into the tokamak plasma has been executed. After modeling the vacuum vessel and the plasma of quasi-D shapes as tori of rectangular cross-sections, the influences of the position and the number of the fueling inputs on the particle density distribution for a given pumping probability and mean free path were investigated.

Numerical Analysis of Flow Distribution Inside a Fuel Assembly with Split-Type Mixing Vanes (분할 형태 혼합날개가 장착된 연료집합체 내부유동 분포 수치해석)

  • Lee, Gong Hee;Cheong, Ae Ju
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.5
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    • pp.329-337
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    • 2016
  • As a turbulence-enhancing device, a mixing vane, which is installed at a spacer grid of the fuel assembly, plays an important role in improving convective heat transfer by generating either swirl flow in the subchannels or cross flow between the fuel rod gaps. Therefore, both the geometric configuration and the arrangement pattern of a mixing vane are important factors in determining the performance of a mixing vane. In this study, in order to examine the flow-distribution features inside a $5{\times}5$ fuel assembly with split-type mixing vanes, which was used in the benchmark calculation of the OECD/NEA, we conduct simulations using the commercial computational fluid dynamics software, ANSYS CFX R.14. We compare the predicted results with measured data obtained from the MATiS-H (Measurement and Analysis of Turbulent Mixing in Subchannels-Horizontal) test facility. In addition, we discuss the effect of the split-type mixing vanes on the flow pattern inside the fuel assembly.

Three Dimensional Computational Study on Performance and Transport Characteristics of PEMFC by Flow Direction (유동방향 변화에 따른 고분자 전해질 연료전지의 성능 및 전달특성에 대한 3차원 수치해석적 연구)

  • Lee, Pil-Hyong;Han, Sang-Seok;Hwang, Sang-Soon
    • Journal of the Korean Electrochemical Society
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    • v.11 no.1
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    • pp.51-58
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    • 2008
  • Many researches for effects of different flow configurations on performance of Proton Exchange Membrane Fuel Cell have extensively been done but the effects of flow direction at the same flow channel shape should be considered for optimal operation of fuel cell as well. In this paper a numerical computational methode for simulating entire reactive flow fields including anode and cathode flow has been developed and the effects of different flow direction at parallel flow was studied. Pressure drop along the flow channel and density distribution of reactant and products and water transport, ion conductivity across the membrane and I-V performance are compared in terms of flow directions(co-flow or counter-flow) using above numerical simulation method. The results show that the performance under counter-flow condition is superior to that under co-flow condition due to higher reactant and water transport resulting to higher ion conductivity of membrane.

A Study on Heat Release Fluctuation Using Various Hydrocarbon Fuels (다양한 탄화수소 연료를 이용한 열방출 섭동 연구)

  • Hwang, Donghyun;Ahn, Kyubok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.6
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    • pp.1-10
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    • 2016
  • For the active control of a combustion instability, a change should be made in pressure fluctuation or heat release fluctuation using an acoustic driver or a secondary fuel injection. Also, to determine the location and timing of a secondary fuel injection, one needs to know the distribution of heat release fluctuation under combustion instability. In the present research, the distribution of heat release fluctuation has been experimentally measured by changing hydrocarbon fuel, inlet velocity, equivalence ratio, and acoustic forcing condition. It was confirmed that heat release fluctuation with regards to vortex shedding was significantly affected by the $Damk{\ddot{o}}hler$ number. Under the cases of the $Damk{\ddot{o}}hler$ number above approximately 4 - 5, hot spot region was generated in the leading edge of vortex and cold spot region was in the trailing edge. On the contrary, the cases of the $Damk{\ddot{o}}hler$ number below 3 showed the opposite trend.

Life Time Estimation of Biodiesel and Biodiesel Blend Fuel from the Oxidation Stability Analysis (바이오디젤 및 바이오디젤 혼합연료의 산화특성 연구에 의한 사용 수명 예측)

  • Jung, Chung-Sub;Dong, Jong-In;Lee, Young-Jae
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.579-584
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    • 2007
  • 대두유로부터 생산된 바이오디젤과 바이오디젤 혼합 연료유를 대상으로 지방산메틸에스터 함량과 화학적 분석을 통해 산화 특성과 오일의 수명 예측 연구를 수행하였다. 바이오디젤, 경유, BD5, BD20은 산화가 진행될수록 산가(Acid number), 동점도(Kinematic Viscosity) 및 밀도(Density)는 증가하였다. 산가 측정결과의 활용에 의해 임의의 온도조건에서 정확한 사용수명을 예측하기 위하여 화학속도론에 의거하여 각각의 연료에 대한 사용수명식을 도출하였다. 도출된 사용수명식으로부터 바이오디젤이 가장 빠르게 산화가 진행되었고 바이오디젤 혼합량이 증가할수록 사용수명이 단축되는 것을 확인할 수 있었다.

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A Study on the Performance of EFI Engine Used Ultrasonic Energy Adding Fuel system(II) -Attaching Importance to the Fuel Spray- (초음파연료공급창치를 이용한 EFI기관의 성능에 관한 연구(II) -연료 분사를 중심으로-)

  • 윤면근;류정인
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.2
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    • pp.80-86
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    • 1997
  • This experiment was undertaken to investigate spray characteristics of the conventional injection system and the ultrasonic energy added injection system. Sauter mean diameter was measured under the variation of injection pressure and the spray distance. To measure the droplet size, we used the Malvern system 2600C. The spray angle and mass distribution were analyzed to the CCD camera and the patternater. After experiment, it was found that the ultrasonic energy added injection system had smaller Sauter mean diameter of droplet, wider mass distribution and wider spray angle than the conventional injection system had.

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Life Time Estimation of Biodiesel and Biodiesel Blend Fuel from the Oxidation Stability Analysis (바이오디젤 및 바이오디젤 혼합연료의 산화특성 연구에 의한 사용 수명 예측)

  • Jung, Chung-Sub;Lee, Young-Jae;Dong, Jong-In
    • New & Renewable Energy
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    • v.3 no.2 s.10
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    • pp.17-23
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    • 2007
  • 대두유로부터 생산된 바이오디젤과 바이오디젤 혼합 연료유를 대상으로 지방산메틸에스터 함량과 화학적 분석을 통해 산화 특성과 오일의 수명 예측 연구를 수행하였다. 바이오디젤, 경유, BD5, BD20은 산화가 진행될수록 산가(Acid number), 동점도(Kinematic Viscosity) 및 밀도(Density)는 증가하였다. 산가 측정결과의 활용에 의해 임의의 온도조건에서 정확한 사용수명을 예측하기 위하여 화학속도론에 의거하여 각각의 연료에 대한 사용수명식을 도출하였다. 도출된 사용수명식으로부터 바이오디젤이 가장 빠르게 산화가 진행되었고 바이오디젤 혼합량이 증가할수록 사용수명이 단축되는 것을 확인할 수 있었다.

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