Numerical simulation of primary atomization in diesel spray at low injection pressure

Atomization involves complex physical processes and interaction gas-liquid. Primary atomization on Diesel spray is not well understood due to the difficulties to perform experimental measurements in the near nozzle field. Hence computational fluid dynamics (CFD) has been used as a key element to understand and improve Diesel spray. A recently new code for incompressible multiphase flow with adaptive octree mesh refinement has been used to perform simulations of atomization at low injection pressure conditions. The multiphase flow strategy to manage different flows is the volume of fluid (VOF) method. The adaptive mesh allows to locally refine the mesh at each time step where a better resolution is needed to capture important gradients instead of using a static mesh with a fixed and high number of cells which, in turns, would lead to an unaffordable computational cost. Even with this approach, the cell number is very high to achieve a Direct Numerical Simulation (DNS) at reasonable computational cost. To reduce the computational cost, two solutions have been explored in the present work: The possibility of removing during the simulation the smallest droplets resulting from the first atomization and the possibility of setting a maximum number of cells of the domain. Following these ideas, the code has been tested with different configurations to understand their effects on numerical stability, the change in different spray parameters and the benefits achieved in terms of execution time. The outcomes have been validated against theoretical models and experimental correlations. e-mails: [email protected], [email protected], [email protected], [email protected]