Abstract: Basing on the assumption that the average torque exerted on the wall surface in an agitated vessel is approximately equal to that offered by a rotating impeller and introducing the conception of flow regime coefficient. a new shear rate model used to calculate apparent viscosity of non-Newtonian fluids is proposed. The impellers investigated are MIG impellers, flat blade disc turbines, pfaudler impellers, plate paddles, anchors and a semielliptical board impeller, diversing widely in geometrical configurations respectively. Three types of cooling tubes (inner helical coil, external helical coil and vertical tubes) are respectively equipped inside the vessels. Using the present model, heat transfer correlations are respectively obtained for the three cooling tube systems. The correlations can be used in the design and scale up of industrial agitated vessels. The results indicate that this model can be used to correlate heat transfercoefficients of non-Newtonian fluids in various cases such as different cooling tube systems, various types of impeller, unbaffle or with vertical tubes as baffles, transitional regime or turbulent regime and jacket side or cooling tube side. Comparison between the present shear rate model and those developed previously is also presented.