ID 416

Numerical examination of the aerodynamic breakup of droplets in chain formation

 

Abstract:

TThe present work investigates numerically using the Volume of Fluid (VOF) methodology the aerody-namic breakup of four Diesel droplets in chain formation at conditions representative for Diesel engines. The Weber (We) numbers examined range from 15 up to 64 and the non-dimensional distances between the droplet centres (L/D0) from 1.25 up to 20. It is observed that for small distances the obtained shapes and breakup modes between the leading and the trailing droplets are different, with the latter experiencing a new breakup mode in the multi-mode regime, termed as “shuttlecock”. This is characterized by an oblique stretching of the droplet at its periphery, induced by the acting of pressure forces at an off-centre region. Moreover, the critical We, breakup initiation time, liquid surface area and drag coefficient of the third droplet of the row, which is regarded as a “representative chain droplet”, are compared with those of an isolated droplet at the same conditions. It is found that for small L/D0 the critical We and breakup time of the representative chain droplet are higher than those of the isolated, while the drag coefficient and liquid surface area are lower.