Laminar Flow Heat Transfer in U-Bend, Paper Validation. CFD approach

Overview of CFD Simulation of Laminar Flow and Heat Transfer in a U-Bend

Project Description

Validated against the paper "Laminar flow and heat transfer in U-bends: The effect of secondary flows in ducts with partial and full curvature," this ANSYS Fluent simulation models laminar flow through a U-shaped tube.

Model Design

The fluid, therminol, has particular characteristics: density of 793.9 kg/m³, specific heat capacity of 2315 J/kg·K, thermal conductivity of 0.116 W/m·K, and viscosity of 0.00173 kg/m·s.  With an inlet speed of 0.21791 m/s, the simulation runs at a Reynolds number of 1000.  Designed in Design Modeller, the U-bend model has a pipe diameter of 0.01 m and a bend radius of 0.015 m.  There are 2,268,000 components in the structured mesh.

Methodology

A constant heat flux of 1156 W/m²·K is applied as the thermal boundary condition on the pipe wall to analyze fluid behavior and heat transfer through the U-bend.

Results and Conclusion

Validated against Figure 14-b of the reference paper, the simulation seeks to confirm fluid temperature variations along the inner wall of the pipe.  A graph of dimensionless position versus dimensionless temperature backs this confirmation.  The Nusselt number is also evaluated at P1 to P5 along the bend; ratios are computed in relation to section P1.  These results are contrasted with dimensionless Nusselt numbers in Figure 19-b of the paper.