2D simulation Eulerian continuum fluid History of engineering & technology STAR-CCM+ VOF air entrainment butadiene chemical and biological processes circulating fluidized bed riser computational fluid dynamics computational fluid dynamics (CFD) conjugate heat transfer drag models dynamic operation eulerian–eulerian fluid properties liquid plunging jet multi-tubular reactor multiphase flow multiphysics multiscale modeling multiscale simulation open-cell foams oxidative dehydrogenation (ODH) reactor design structured reactors void fraction volume of fluid (VOF) volumetric heat sources waste water treatment