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摘要
The spray produced by the %26quot;Christmas tree%26quot; disintegration mode with inner and outer gaseous coflows is analyzed in this article. In the first part, the spray angle is investigated from snapshots and in the second part, the characterization of the dilute phase, such as diameter, mean velocities, and fluctuations of droplets, is carried out by using a phase Doppler analyzer. The results are the following: The initial spray angle, larger than the one observed without outer gas jet, decreases with the growth of ambient gas density. The Sauter mean diameter, rising from the spray axis to the out-skirt of the flow, is reduced more effectively by the inner gas. It rises with the increase of the ambient pressure or the fall of the inner gas momentum flux through its respective section. The radial profiles of the mean axial velocity are compared with the Lorentz curve, the velocity declining slowly toward the spray periphery. Then the evolution of the mean axial velocity on the spray axis and the corresponding half width at half maximum are analyzed. Finally, the axial velocity fluctuation is maximal on the spray axis in the near field. This phenomenon is related to the periodic formation of droplets of the Christmas tree regime.
- 出版日期2014
