ID 209

Quantitative study of internal flow and near nozzle jet breakup under flash boiling test conditions

Shangze Yang
School of Mechanical Engineering, Shanghai Jiao Tong University, National Engineering Laboratory for Automotive Electronic Control Technology, Shanghai, China
China

Min Xu
School of Mechanical Engineering, Shanghai Jiao Tong University, National Engineering Laboratory for Automotive Electronic Control Technology, Shanghai, China
United States

David L. S. Hung
University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai, China
United States

Xuesong Li
School of Mechanical Engineering, Shanghai Jiao Tong University, National Engineering Laboratory for Automotive Electronic Control Technology, Shanghai, China
China

Abstract:

The atomization of fuel spray plays a vital role in clean economy and emission reduction. Flash boil-ing sprays which are achieved by increasing the fuel temperature have been utilized to improve fuel evaporation and atomization efficiency. However, the dynamic interaction between the gas phase and liq-uid phase of the flash boiling sprays has not been adequately investigated yet. In this study, quantitative study of internal flow and near nozzle spray breakup were carried out based on a two-dimensional trans-parent nozzle via microscopic imaging. N-hexane was chosen as test fluid with an injection pressure of 7 bar. Fuel temperature varied from 63℃ to 138℃, which covered a wide range of superheated conditions. With the experimental results, the correlation between the internal flow and spray liquid jet breakup is established and the impact of the correlation on the properties of the flash boiling sprays is presented. Furthermore, dynamic interaction between the gas phase and liquid phase in the nozzle and out of the nozzle is analyzed with a center of mass scheme. It is found that the dynamic features of the flash boiling sprays are closely connected with the dynamics of the in-nozzle flow. Such observation suggests that modifying flash boiling bubble characteristics can potentially be utilized to actively control flash boiling sprays for spray performance improvement.