Experimental analysis of heat transfer enhancement in shell and helical tube heat exchangers

► Experimental setup and Wilson plot technique is used for this study. ► Optimum coil pitch, coil diameter and flow rates are proposed for heat exchanger. ► By decreasing coil diameter and increasing pitch, shell Nusselt number increase. ► By increasing coil diameter and decreasing pitch, tube Nusselt Number increases. ► By maximum coil diameter and pitch, the highest heat transfer rate is obtained.