Airlift Reactor – Experiment and CFD Simulation

Airlift reactors are modified bubble columns, where internal walls separate the up- and downward flow sections. Since appropriate experiments with locally resolved flow parameters are hardly available, a CFD-grade dataset has been created to validate the HZDR baseline closure model set for an internal airlift reactor. The measurements include many important gas-liquid flow characteristics like gas volume fraction, liquid velocity, turbulence parameters and bubble size distributions for both, the riser and the downcomer. CFD simulations of the test facility were conducted using the URANS concept and compared to the experiments to show strengths and drawbacks of the used closure models. The results reveal that the CFD simulations are capable to predict void fraction in the riser as well as the liquid velocity over the whole cross section quite well. However, the void fraction along the downcomer could not be reproduced in the simulations.