Parabolic Solar Collector with Nano Fluid: Paper Validation

Parabolic Solar Collector with Nano Fluid, Paper Numerical Validation, ANSYS Fluent Tutorial

Description

This project examines heat transfer within the tube of a parabolic solar collector carrying water, based on the reference paper "Thermal performance analysis of solar parabolic trough collector using nanofluid as working fluid: A CFD modeling study." Results are validated against the paper's published data using ANSYS Fluent.

In a parabolic trough collector, a tube runs along the focal line of a curved reflector, which concentrates incoming solar radiation onto the tube to heat the fluid inside. Here, only the water-carrying pipe itself is modeled — an aluminum tube split into upper and lower wall sections, reflecting the uneven way sunlight strikes each side. Water enters at a Reynolds number of 30,000 and 320 K, which works out to an inlet velocity of 0.5024043 m/s once the fluid's thermophysical properties are factored in.

The 3D geometry, built in Design Modeler, takes advantage of the tube's symmetry to model only half a semi-cylindrical section: a thin outer solid wall wrapping a fluid conduit 0.06 m in diameter, 2 m long, with a 0.002 m wall thickness. ANSYS Meshing produced a structured grid of 1,475,000 elements.

Methodology

Following the reference paper's relationships, the tube wall carries two distinct constant heat fluxes — 750 W/m² on top and 19,500 W/m² on the bottom — capturing the asymmetric solar loading characteristic of a trough collector, where the reflector concentrates far more energy onto the underside of the tube than reaches the top directly.

Conclusion

The simulation centers on the Nusselt number, calculated at the fluid-wall interface using the Report command and validated against the paper's reported values. Consistent with how the reference defines its own results, this comparison focuses on the fully developed flow region near the pipe's outlet.

Checking the Nusselt number at several distances from the outlet against the paper's Figure 4 (at Re = 30,000) shows the two data sets converging as the flow approaches full development — the closer to the pipe's end, the tighter the match, confirming the simulation's validity in that regime.

Additional 2D and 3D contours of pressure, velocity, and temperature round out the results, with the 2D views taken across the model's symmetry plane.