Experimental Study on Spray Characteristics of The Internal Impinging Nozzle = Experimental Study on Spray Characteristics of The Internal Impinging Nozzle

다국어 초록 (Multilingual Abstract)

The internal impinging nozzle with a bluff body set inside can form a periodic oscillating spray, which is a novel approach of atomization. In this paper, the flow distribution characteristics of the spray are studied with low-pressure water as the medium. Meanwhile, the characteristics of spray cone angle, oscillating frequency, spatial distribution of droplet velocity and particle size are also studied with high-speed Schllieren technique and Malwen particle size analyzer. The results demonstrate that with the increase of the injection pressure, the spray cone angle is almost constant, while the spray oscillating frequency increases gradually, which is tantamount to the variation trend of axial velocity and radial velocity of the droplet. When the injection pressure is elevated from 0.16MPa to 0.18MPa, at the same position, the increase of droplet axial velocity distinctly reaches a maximum. Furthermore, with the development of the spray, the particle size decreases accordingly, and the velocity of the well atomized area near the spray symmetrical center axis is also gradually reduced. The farther away from the nozzle outlet, the more pronounced the symmetry of the spatial distribution of the axial velocity and radial velocity becomes. Moreover, when the injection pressure reaches 0.16MPa, at the position 250mm away from the outlet, the particle size achieves a minimum, and the spray obtains a stable distribution, which is rarefied and uniform in the middle area, while generous on both sides. With the injection pressure increasing to 0.18MPa, the flow of the well atomized area near the spray symmetrical center axis reaches its maximum, and that of the area farthest away from the symmetry center is also raised by degrees as the injection pressure increases.