Heat transfer correlation in high prandtl (high Schmidt) number fluid in votator type scraped surface heat exchanger

An experimental investigation to obtain heat transfer correlation in a Votator type scraped surface beat exchanger with two-blades was performed by an electro-chemical method. Measurements were carried by mass transfer under diffusion control in a ferricyanide/ferrocyanide redox electrochemical reaction. The heat transfer correlation was obtained from an analogy of heat and mass transfer. Local heat transfer coefficients on the wall of the outer column of the exchanger was measured by varying the rotational Reynolds number, flow rate of fluid, Prandtl number and equivalent diameter in order to obtain the unity thermal design equation. The time averaged local Nusselt number in a high Prandtl number fluid was found to be correlated by the following equation: Nu=1.53Re_r^0.51Pr^0.33 (D_o/D_e)^0.44 (1320<Pr<5810, 2.94<D_o/D_e<7.2) where Re_r and D_e are the blade rotational Reynolds number and equivalent diameter respectively.