Convective heat transfer enhancement of graphene nanofluids in shell and tube heat exchanger

• Developing higher convective heat transfer behavior of graphene nanofluids.
• Effect of different parameters on convective heat transfer coefficients.
• Preparation of good nanofulid from graphene.
• Convective heat transfer coefficient enhanced up to 35.6% by graphene nanofluid.

Current research suggests a promising future for graphene nanofluids. The main focus of this research is on developing higher convective heat transfer behavior of graphene nanofluids through the shell and tube heat exchanger under laminar flow. Graphene nano sheets were prepared by CVD method and their morphology was investigated by SEM and Raman spectroscopy. The convective heat transfer coefficients of graphene nanofluids based on water in the entrance region and under laminar conditions have been measured. Also the effect of temperature and concentration on convective heat transfer coefficients of graphene nanofluids has been discussed. According to the results, adding 0.075% of graphene to the base fluid contributes to an improvement of thermal conductivity up to 31.83% at saturation concentration of graphene and an enhancement in heat transfer coefficient which depends on the flow conditions. The convective heat transfer coefficient of graphene nanofluids at 38 °C enhanced up to 35.6% at a concentration of 0.1 wt% compared with pure water.