Influence of additive to bulk viscosity ratio on inline blending in laminar flow

In the laminar flow regime (Remixer < 10), the effect of additive and bulk viscosity on Lmix/D was characterised using the viscosity ratio μa/μb as opposed to the modified Reynolds number, Re*. The laminar flow Lmix/D results demonstrated a strong influence of μa/μb outside a fairly narrow range around μa/μb = 1. The increase in Lmix/D when μa/μb < 1 (dilution of viscous bulk) was always due to the presence of single or multiple strands of low viscosity additive (striations) which broke through Lmix/D = 54 under some conditions.