In the design chain of novel biofuels, there are two streams of information go into the simulation of atomization: one comes from biorefinery, which contains the physical properties of liquid biofuels, for example, density, viscosity and surface tension; the other comes from engine development, which contains the low temperature combustion operating conditions, such as ambient pressure, ambient temperature and injection pressure.

The multi-scale, multi-physics simulation of atomization of TMFB cluster is build on modern computational framework. It requires massive parallel computational infrastructure, which is supported by the Jülich Aachen Research Alliance (JARA), providing parallel computing, parallel I/O and parallel data management. Key components of the computational framework are the physical and mathematical models and numerical solvers for the high-fidelity simulations, which include 1) the high-performance unstructured finite-volume flow solver for the Navier-Stokes equations, 2) the level-set method based liquid-gas interface tracking and the surface tension model, 3) the Lagrangian method based droplet dispersion solver. The multicomponent evaporation model for fuel blending will be developed in the second phase the TMFB cluster.

Main results of the simulations are the droplet size and velocity distributions, as well as the 3 dimensional unsteady turbulent flow field. The feedback information also contains two streams of information. One goes towards biorefinary: which answers the questions – does the atomization of the novel biofuel similar as the traditional fuels? how critical are the influence of those properties on the fuel/combustion flexibility? As for the engine development, better understanding of the atomization process will assist designing advanced injection/mixture formation strategies for smokeless/NoX free combustion.

The droplet size distribution, resulting from the atomization process, is important for the spray vaporization and combustion. Smaller droplets vaporize faster due to their larger surface to volume ratio compared to the larger droplets. Therefore, sprays contain mostly small droplets will have shorter evaporation time, leaving more time for the fuel-vapor/air mixing. A well-mixed fuel-air mixture once ignites, the combustion will behave more like a premixed flame; if the ignition happens during the mixing process, the combustion is still mixing controlled diffusion flame.