• Title/Summary/Keyword: Fuel Flow

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A Study on the Optimization of Fuel Metering for the Lean Combustion System in a Gasoline Engine (I) (가솔린 자동차의 희박연소시스템 적용을 위한 연료공급 최적화에 관한 연구 (I) - 가솔린 인젝터의 연료분열특성에 관한 연구 -)

  • Yoon, S.J.;Cho, D.J.;Pang, D.Y.
    • Journal of ILASS-Korea
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    • v.3 no.3
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    • pp.33-41
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    • 1998
  • In recently, a study on the lean combustion is investigated intensively, because it is expected that this method may decrease the harmful exhaust gas and improve fuel economy in gasoline engine. The problems of lean combustion system in gasoline engine are ignition difficulty, misfire and instability of combustion. The investigation on the optimization of fuel metering and the control of mixing gas flow may be critical to improve the performance of lean combustion. In the fuel injection gasoline engine, the formation of mixture influences strongly on the engine performance such that the importance of fuel metering system becomes apparent. First of all, a study on the fuel breakup characteristics of gasoline fuel injector was carried out in this paper. Fuel injectors are pintle and 4hole-2spray type. The purpose of this study is to clarify the atomization mechanism of spray injected into atomosphere field through electronic controlled-fuel injectors, and to analyze spray characteristics such as drop size distribution and mean drop diameter produced at fuel injector. In this paper, the spray development is observed by taking photograps using 80mm still-camera system, and drop sizes are measured by PMAS. From these experiment, spray pattern injected from gasoline fuel injectors was investigated clearly. Also, it was found that SMD and drop size distribution of injected fuel spray from gasoline fuel injectors.

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CFD simulation of flow and heat transfer characteristics in a 5×5 fuel rod bundles with spacer grids of advanced PWR

  • Wang, Yingjie;Wang, Mingjun;Ju, Haoran;Zhao, Minfu;Zhang, Dalin;Tian, Wenxi;Liu, Tiancai;Qiu, Suizheng;Su, G.H.
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1386-1395
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    • 2020
  • High fidelity nuclear reactor fuel assembly simulation using CFD method is an effective way for the structure design and optimization. The validated models and user practice guidelines play critical roles in achieving reliable results in CFD simulations. In this paper, the international benchmark MATiS-H is studied carefully and the best user practice guideline is achieved for the rod bundles simulation. Then a 5 × 5 rod bundles model in the advanced pressurized water reactor (PWR) is established and the detailed three-dimensional thermal-hydraulic characteristics are investigated. The influence of spacer grids and mixing vanes on the flow and hear transfer in rod bundles is revealed. As the coolant flows through the spacer grids and mixing vanes in the rod bundles, the drastic lateral flow would be induced and the pressure drop increases significantly. In addition, the heat transfer is enhanced remarkably due to the strong mixing effects. The calculation results could provide meaningful guidelines for the design of advanced PWR fuel assembly.

Performance Characteristics with Various Fuel Composition and Temperature for an External Type Fuel Pump in LPLi System (LPLi 시스템에서 외장형 펌프의 연료조성 및 온도에 따른 성능특성 연구)

  • Nam, Deok-Woo;Yoon, Jun-Kyu;Lim, Jong-Han
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.5
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    • pp.566-575
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    • 2011
  • Since LPG (Liquefied petroleum gas) fuel supply system has an advantage of low emission characteristics, many studies have been conducted. In spite of the advantage of LPG supply system, a higher vapor pressure and lower viscosity than diesel or gasoline fuel may cause unstable running of fuel pump by the deterioration in lubrication performance and chemical reaction with rubber parts than that of diesel and gasoline fuel. Therefore its physical properties can cause the deterioration of durability. In this research, we developed an external type LPG pump which has the advantage of the price competitiveness and the convenient maintenance for LPLi system. The experiments were carried out in order to assess characteristics of the external type fuel pump at different fuel composition and temperature. As a result, there aren't any differences between internal and external type pump performance. It is observed that the same level of efficiency was maintained for both pumps as flow rate was increased with higher fuel temperature and more contents of propane in the fuel. And the pressure difference in LPLi system is maintained at constant with the various fuel compositions and temperatures due to their own characteristics of fuel supply system.