Accelerating Diesel Spray Simulation by Large-scale Parallel Computing with OpenFOAM

Abstract

The accelerating diesel spray simulation is performed with large-scale parallel computing by use of OpenFOAM 2.2.2. The “aachemBomb”, that is one of tutorials to simulate a diesel spray flame in a constant volume vessel, is used to measure parallel computing performance until 1024 cores. The maximum computational speeds of non-evaporative spray and spray flame with one-step reaction are 14 times (128 cores) and 43 times (128 cores), respectively, compared to the sequential computing. In the spray flame simulation with the reduced reaction mechanism (29 species, 52 reactions), the maximum computational speed is 149 times (512 cores). Then LES of evaporative spray (Spray A) are calculated. The results with the grid that is 9,440,000 cells and the minimal grid size of 0.25 mm indicate that the vapor and liquid penetration is well predicted. The CPU time is 90.5 days with sequential computing from the injection start to 5.0 ms, while the CPU time with parallel computing of 512 cores is 14 hours. The computational speed is 154 times compared to the sequential computing.