Simulation of Liquid Film Spreading on Tip of Spray Injector
Eiji Ishii,
Kazuki Yoshimura,
Tomoyuki Hosaka
Issue:
Volume 10, Issue 2, March 2021
Pages:
30-36
Received:
9 March 2021
Accepted:
25 March 2021
Published:
1 April 2021
Abstract: The behaviors of fuel films adhering to the tip of a fuel injector for automotive gasoline direct-injection engines was simulated by the computational fluid dynamics. Liquid film adhering to the tip of the fuel injector is a source of carbon deposits; the film spreads on the surfaces of the tip and remains there under certain wetting conditions. The deposit build-up can clog the injector nozzles, which can alter the spray pattern, furthermore, deposits on the tips of injectors are a source of particulate matter (PM) discharged from the engine. In order to prevent air pollution, it is essential to develop a technology to reduce PM. The spread of fuel adhering to the tip of a fuel injector was simulated using the moving particle semi-implicit method, and a previously developed particle/grid hybrid method was used to study the effects of spray plumes. The simulated distribution of the film qualitatively agreed with the measured distribution of carbon deposits. Fuel film formed on the concave and convex wall surfaces. The fuel film and carbon deposits were unevenly distributed in the air flow direction. Investigation of the behaviors of floating droplets around the tip between fuel injections revealed that the droplets were pulled toward the tip wall due to a reverse air flow generated by the fuel plumes ejected by the injector nozzles. These droplets then merged as a part of the fuel film, which spread toward the injection nozzles due to the air flow directed at the nozzles. Some of the film was sucked into the spray plumes and then re-injected into the air region again. The simulated fuel film behaviors on the tip qualitatively agreed with the measured ones. Furthermore, the simulation showed that optimizing the surface shape of the fuel injector tip, particularly the concave portion, is important for reducing particulate matter.
Abstract: The behaviors of fuel films adhering to the tip of a fuel injector for automotive gasoline direct-injection engines was simulated by the computational fluid dynamics. Liquid film adhering to the tip of the fuel injector is a source of carbon deposits; the film spreads on the surfaces of the tip and remains there under certain wetting conditions. Th...
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Effects of Some Key Parameters on the Overall Performance of Gas Turbine
Pengfei Su,
Jianmin Gao,
Shiquan Zhao,
Xiangling Kong,
Yu Fang
Issue:
Volume 10, Issue 2, March 2021
Pages:
37-49
Received:
6 April 2021
Accepted:
23 April 2021
Published:
8 May 2021
Abstract: A method for power plant Gas Turbine overall performance evaluation was developed based on the thermodynamic cycle. Some key parameters affecting the simple cycle efficiency and power of the GT, such as compressor pressure ratio, turbine inlet temperature, compressor efficiency, compressor exit diffuser Cp, combustor pressure loss, turbine efficiency, OTDF, RTDF, blade metal allowable temperature and turbine exit diffuser Cp has been studied across a wide range of possible operating conditions. The effects on simple cycle of GT efficiency, GT specific power and turbine exit temperature of these parameters were discussed: The compressor pressure ratio should be chosen to give an optimumGT specific power, and should match turbine inlet temperature; When compressor efficiency increases 1%, the GT efficiency increases about 0.3%, while turbine efficiency increases 1%, the GT efficiency increases about 0.6%; When compressor exit diffuser Cp increases 0.1, the GT efficiency increases about 0.1%, while turbine exit diffuser Cp increases 0.1, the GT efficiency increases about 0.25%; RTDF is more important than OTDF for GT efficiency, When RTDF increases 0.05, the GT efficiency decreases about 0.15%, but When OTDF increases 0.05, the GT efficiency only decreases about 0.02%; When combustor pressure loss increases 1%, the GT efficiency decreases about 0.2%, but combustor pressure loss also effect turbine Nozzle1 cooling design; these parameters should be carefully considered in a new GT design.
Abstract: A method for power plant Gas Turbine overall performance evaluation was developed based on the thermodynamic cycle. Some key parameters affecting the simple cycle efficiency and power of the GT, such as compressor pressure ratio, turbine inlet temperature, compressor efficiency, compressor exit diffuser Cp, combustor pressure loss, turbine efficien...
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