Numerical investigation of hydrodynamics and heat transfer for Bingham-pseudoplastic fluids in an industrial coiled stirred tank

Abstract

AbstractComputational fluid dynamics (CFD) was used to investigate the influence of complex rheological properties for Bingham-pseudoplastic fluids on hydrodynamics and heat transfer performance in an industrial polymerization coiled agitated reactor. The fluid rheology was described by the Herschel–Bulkley rheological model. The power consumption obtained by CFD simulation was in good agreement with the plant data. The relationship between the Metzner–Otto constant and power-law index for dual axial flow impellers was investigated. The hydrodynamics strongly depends on the rheological parameters and rotational speed. The flow domain is composed of two parts: the cavern around the impellers, and the stagnant zone adjacent to helical coils and tank wall which resulting in poor mixing and heat transfer performance. With the increase of rotational speed, the stagnant zone could be effectively eliminated, while the heat transfer performance could be significantly improved.