Nanofluid and Twisted Tape Inserts in a Tube: Paper Validation

Al2O3-Water Nanofluid in a Tube with Twisted Tape Inserts, Paper Numerical Validation, CFD Simulation Tutorial by ANSYS Fluent

Description

This project simulates Al2O3-water nanofluid flow inside a circular tube fitted with twisted tape inserts using ANSYS Fluent, with results compared and validated against the reference article "Study on heat transfer and friction factor characteristics of Al2O3-water through circular tube twisted tape inserts with different thicknesses." The Al2O3-water fluid enters the computational domain at an initial temperature of 300 K and a velocity of 0.716 m/s, corresponding to a Reynolds number of 500, flowing through a multi-staged twisted circular tube whose outer wall is exposed to a heat flux of 5000 W/m², progressively raising the fluid's temperature as it travels through the tube.

The geometry was designed in Design Modeler and meshed in ANSYS Meshing using a structured grid totaling 2,146,882 elements.

Methodology

Nanofluids are compounds consisting of a base fluid infused with fine solid particles at the nanoscale. While a full multiphase model — explicitly resolving both the base fluid and the dispersed solid particles — can capture this behavior, doing so carries a substantial computational cost. This simulation instead uses an alternative, more efficient approach: defining a single new "nanofluid" material within the computational domain, whose effective properties (density, specific heat capacity, thermal conductivity, and viscosity) are calculated using established formulas that combine the base fluid and nanoparticle properties.

Conclusion

The simulation results were compared directly against the reference paper using the Nusselt number trend across varying Reynolds numbers, with validation performed specifically at Re = 500. The comparison showed a low error rate, confirming that the current simulation was performed correctly.

Pressure and velocity contours further reveal that nanofluid pressure decreases progressively along the tube as it passes through the twisted tape inserts, since these obstacles disrupt the flow and induce pressure loss. At the same time, the nanofluid's temperature rises more substantially than it would in a plain tube — the spiral twisted tape forces the fluid to travel a longer path length, increasing its contact time with the heated outer wall and enhancing overall heat transfer.