In this paper local now investigations under isothermal conditions have been established for a narrow annular gap reactor (NAGR, given by a rotor/stator system with a radius ratio of r(i)/r(o), = 0.8) including two wall scraper blades of different geometry. Two-dimensional laminar flow fields are considered (with Reynolds numbers below Re < 82.6), based on numerical flow simulations, where validations with experimental velocity measurements are in good agreement. Comparisons of the macroscopic flow structuring behaviour are shown for Newtonian and inelastic shear-thinning fluids based on velocity profiles, secondary flows, hydrodynamic pressure contours, shear stress and energy dissipation, by varying the rotor velocity (described in terms of a characteristic rotational Reynolds number Re), the scraper blade angle (beta) and the non-Newtonian flow behaviour (power-law exponent n). (C) 2001 Elsevier Science Ltd. All rights reserved.