Single phase fluid-stator heat transfer coefficients for a multi-stage rotor-stator spinning disc reactor are presented. The overall heat transfer coefficient is obtained by fitting experimentally obtained steady state outlet temperatures loan engineering model for the fluid flow inside the rotor-stator cavities. Heat transfer measurements are done for gap ratios of G=0.017 and 0.03, rotational Reynolds numbers of Re-omega=0 to 12 x 10(5) and superposed dimensionless throughflow rates of C-w=211-421. From the overall heat transfer coefficient values for the fluid-stator Nusselt number Nu(s) are obtained. For all values of C-w and G, Nu(s) increases more than a factor of 4 by increasing Re-omega from 0 to 1.3 x 10(5). A throughflow dominated regime occurs for Re-omega<0.2 x 10(5), where Nu(s) increases with increasing C-w and decreasing G. For Re-omega>0.2 x 10(5), rotation dominates the heat transfer and no influence of C-w and G on Nu(s) is observed. The thermal performance of the multi-stage rotor-stator spinning disc reactor, quantified in the volumetric overall heat transfer coefficient, increases from U(0v)AV(R)(-1)=046 +/- 0.2 to 0.93 +/- 0.16 MW m(-3) K-1 by increasing Re-omega from 0 to 45 x 10(5). The volumetric overall heat transfer coefficient of the multi-stage rotor-stator spinning disc reactor is more than a factor of 5 higher than in conventional tubular reactors. (C) 2014 Elsevier Ltd. All rights reserved.