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Affiliation of Author(s):能源与动力学院

Journal:Neiranji Xuebao

Abstract:Atomization mechanism of the air-assisted injector with Laval nozzle structure was studied on a two stroke spark-ignited aircraft heavy fuel engine. When the nozzle structure of the injector is determined, the gas flow pattern in the Laval tube varies with the actual pressure ratio of the vapor phase. According to the Lagrange theory of the twophase flow, effects of air inlet pressure of the air-assisted injector on the two-phase flow patterns in the Laval nozzle were analyzed by CFD(computational fluid dynamics)simulation with the Fluent software. The results show that when the gas pressure ratio reaches 6.5 in the Laval nozzle, the air is ejected from the nozzle at a supersonic speed. In the meantime, a negative pressure region and two symmetrically-distributed vortexes are formed below the outlet of the nozzle. Due to the interaction of supersonic auxiliary air entrainment and the double-vortexes, the aerodynamic force overcomes the droplet surface tension, leading to a low spray SMD. The quality of atomization is also insensitive to fuel types. When the vapor pressure ratio increases to 7.5, there is a little changes in the distribution of spray particles and the SMD. However, the mass of the auxiliary air increases considerably, leading to more consumption of the power of the air compressor. © 2018, Editorial Office of the Transaction of CSICE. All right reserved.

ISSN No.:1000-0909

Translation or Not:no

Date of Publication:2018-01-01

Co-author:Wang, Siqi

Correspondence Author:yhq