Performance characteristics of a novel shell and tube heat exchanger with shell side interstitial twisted tapes for viscous fluids application

•Thermal-hydraulic characteristics of heat exchanger with shell side interstitial twisted tapes.•Results indicate strong potential of such heat exchanger where low pressure drop is key requirement.•Correlations estimating Nusselt number and Darcy friction factor are proposed. A unique shell and tube heat exchanger with interstitial twisted tapes was tested with propylene glycol/water solution. Propylene glycol concentration was varied between 0 and 40% by volume. Same size conventional shell and tube exchanger with single segmental baffles was also tested under similar temperature and flow conditions. Results from the two exchangers were then compared. The new design heat exchanger showed better thermal enhancement index for the whole range of fluid concentrations. Correlations for Nusselt number and Darcy friction factor were proposed for both heat exchangers.