ABSTRACTThe residence time distribution (RTD) studies were conducted to predict the flow characteristics in thin film SSHE. the experiments were conducted at zero heat flux using water as working fluid. A pulse input in form of saturated sodium chloride solution was used as the disturbance at inlet and the response in form of electrical conductivity was measured at outlet. Thirty‐two trials were conducted at different flow rates, number of blades and rotor speeds. the E‐curves were plotted. It was inferred that the flow in thin film SSHE approximates to plug flow. Also, as the mass flow rate increased, RTD improved. the increasing number of blades resulted in appreciable improvement in RTD. the rotor speed had similar effect as that of number of blades on RTD. However, the number of blades had more profound effect as compared to rotor speed. If the rotor design is modified then RTD can be improved and simultaneously the power consumption can be kept at mini