A Direct Numerical Simulation of a Turbulent Stirred Vessel Driven By a Rushton Turbine

New results will be presented from a Direct Numerical Simulation (DNS) of the just turbulent flow field, at Re=7300, in a stirred vessel provided with baffles and driven by a Rushton turbine. The simulations have been carried out by means of a Lattice Boltzmann solver, written in C, on a lattice comprising some 30 billion nodes, carrried out at the Irish Centre for High-End Computing ICHEC in Dublin.

The results of this simulation are compared with experimental data from the literature and with the results of the less refined DNSs reported earlier. The main variables of interest are the turbulent kinetic energy and its dissipation rate, phase averaged as well as phase resolved, which can be calculated from the outcome of such a DNS at any position in the vessel. Also turbulent spectra can be obtained in this way and some spectra will be presented for some positions in the vessel.

The idea behind performing DNSs for stirred vessel is to provide a yardstick for assessing the findings of Large Eddy Simulations and for evaluating the performance of sub-grid scale models essential for such LESs. Even experimental data may be assessed by means of a DNS as the resolution attainable in DNSs is better than in experiments.