The effect of turbulence stimulation caused by dividing a short duct into seven cylindrical segments and setting them in three different arrays at one value of displacement ratio was studied by the use of the electrolytic technique. The inlet of the duct was connected to the plenum with a diffuser causing a non-developed flow in the duct. One value of contraction ratio between the plenum and the tested duct was in use. Schmidt number was 1590. Mean values of the mass/heat transfer coefficient for each segment and the friction losses for the whole ducts were measured for Reynolds numbers spanning the range 7600-44200. Correlations on the mean Chilton-Colburn coefficient were stated for the whole duct of three types. Performance analysis of the ducts was done at equal surface area for two common cases of equal flowrate and pumping power. The results might be used, e.g. in the design of turbine blade cooling channels and of some highly effective shell-and-tube heat exchangers. (C) 1997 Elsevier Science Ltd.