Turbulence

Heat transfer coefficient

Critical heat flux

Heat transfer

Materials science

Convective heat transfer

Reynolds number

Heat transfer enhancement

Dynamic scraped surface heat exchanger

Concentric tube heat exchanger

Heat exchanger

Plate heat exchanger

Thermodynamics

Physics

Pressure drop

Composite material

Shell and tube heat exchanger

Nanofluid

Mechanics

Micro heat exchanger

Plate fin heat exchanger

Case Studies in Thermal Engineering

The convection heat transfer in a countercurrent double-tube heat exchanger with various fins in a turbulent flow is investigated. The suitable heating or cooling process of fluids is the effective use of the double-pipe heat exchanger. We use water-aluminum oxide nanofluid and water-titanium dioxide at four concentrations (0.4%, 2%, 4%, 6%) as the cold fluid in the inner tube and water as the hot fluid in the annular space. The single-phase model for nanofluid modeling and the standard k-ε model with scalable wall function for simulating the turbulent flow is utilized. To better examine this novel geometry, its performance is compared with simple and rectangular-finned geometries. The results show that the water aluminum oxide nanofluid has a better convection heat transfer coefficient than water titanium dioxide and pure water. Raising the nanofluid concentration from 0.4% to 6% increases the convection heat transfer coefficient by 12%. Heat exchangers with a rectangular and curved fin have 81% and 85% better efficiency than the heat exchanger without a fin. The novel geometry causes a smaller pressure drop despite its higher convection heat transfer coefficient. Also, it is shown that with raising the Reynolds number and nanofluid concentration, the pressure drop increases.

Novel usage of the curved rectangular fin on the heat transfer of a double-pipe heat exchanger with a nanofluid