Experimental investigation of heat transfer enhancement of Fe2O3-CNT/water magnetic nanofluids under laminar, transient and turbulent flow inside a horizontal shell and tube heat exchanger

• Convective heat transfer was enhanced under laminar, transient and turbulent regime flow conditions.
• Hybrid Fe2O3-CNT/water magnetic nanofluids prepared for the first time.
• Perfect stability of nanoparticles in suspensions has been obtained for Hybrid Fe2O3-CNT/water magnetic nanofluids.
• The highest heat transfer coefficient enhancement was 27.69% in 0.1 wt.% and 48.19% in 0.2 wt.%.

In the present study, enhancement of Fe2O3-CNT magnetic nanoparticles inside a horizontal shell and tube heat exchanger under laminar, transient and turbulent flow with three different heat fluxes was investigated. For this purpose, Fe2O3-CNT magnetic nanoparticles with 30 nm diameter and distilled water as base fluid were used. The primary aim is to evaluate the effect of different weight concentration and temperatures on convective heat transfer. Increasing the weight concentration and temperatures leads to enhancement of convective heat transfer coefficient. The convective heat transfer of Fe-CNT/water magnetic nanofluids with two concentrations 0.1 and 0.2 wt.% were also measured under different flows (Laminar, Transient and Turbulent) in a horizontal shell and tube heat exchanger. It was observed that hybrid Fe2O3-CNT magnetic nanofluids showed higher heat transfer coefficient compared to the base fluid. Results revealed that the heat transfer coefficient for laminar and turbulent flow at 0.1% weight concentration was enhanced 13.54% and 27.69%, respectively. Also at 0.2% weight concentration for laminar and turbulent flow enhanced 34.02% and 37.50% in comparison with distilled water.