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To study the effects of various parameters on the fuel distributions, planar laser induced fluorescence(PLIF) was applied to an operating engine. Particularly, the effect of an air-shroud injector was investigated in the cold condition. Iso-octane was used as the fuel and gasoline(10%) was added as a fluorescing tracer. The fuel distributions during the whole processes of intake and compression were investigated at firing condition and analyzed qualitatively. In addition, flame images were acquired to understand the combustion characteristics. In cold and fuel injection during intake valve closed conditions(IVC), a number of fuel droplets flowed into the combustion chamber in the early and middle stage of intake process and the sizes of droplets were smaller than several tens of μm at both injectors; regular dual stream(D/S) and air-shrouded(A/S). Considerable amount of droplets remained until the late stage of the compression process.

Spray tip penetration and dispersion in high pressure diesel engines have been simulated experimentally with a special emphasis on the effect of swirl. A constant volume chamber was designed to be rotatable in order to generate a continuous swirl and to have the flow field closely resembling a solid body rotation. Emulsified fuel was injected into the chamber and the developing process of fuel sprays was visualized. The effect of swirl on the spray tip penetration was quantified through modeling. Results show that the spray tip penetration is qualitatively different between low and high pressure injections. For high pressure injection, good agreement is achieved between the experimental results and the modeling accounting the effect of swirl on spray penetration. For low pressure injection, reasonable agreement is obtained. The modeling result can be used as basic design data in diesel injector development.

Conventional aircraft use constant-speed drive to generate constant frequency 400-Hz power of relatively good quality and distribute it at 115/200 V. A detailed study revealed that this power type is not the optimal choice for present and future aircraft applications. This paper presents the advantages and disadvantages of various generation and distribution systems and the factors to be considered in selecting an electric power system. For medium and large size STOL aircraft, it appears that variable-frequency generation and high-voltage d-c distribution with secondary square wave a-c distribution may be superior to the conventional system.