Nanofluids are special liquids made by adding very small particles to a base fluid like water. A Nanofluid Heat Transfer By Nusselt Number CFD simulation helps engineers understand how these fluids can improve cooling. This is a study of convective heat transfer, which is how heat moves with a fluid. The Nusselt number is a very important value that tells us how effective this heat transfer is. For this computer model to be useful, we must check it against known science. This is called a Nanofluid Heat Transfer CFD Validation. We use ANSYS Fluent to run the simulation and then compare our calculated Nusselt number to the answer from a famous math formula. This check proves our computer model is accurate and can be trusted.

Simulation Process: Fluent Setup, Single-Phase Modeling for Nanofluid Analysis

To prepare our Nanofluid Heat Transfer By Nusselt Number Fluent simulation, we first modeled a sphere with a diameter of 1 cm. We then created a high-quality mesh around it with 1,398,307 cells. The mesh cells are very small near the sphere’s surface to capture the heat transfer details correctly. For this study, we used the single-phase nanofluid model. This means we treated the water and Al2O3 nanoparticles as one single fluid but with special new properties for density, viscosity, and thermal conductivity. The fluid flow was set to have a Reynolds number of 11,190. As given in the literature, the following analytical formulation governs Nusselt Number:

In our case problem, Reynolds is 11190.

Post-processing: CFD Validation, Analyzing Flow Physics and Nusselt Number

To validate our result, we used a well-known analytical formula, which gave a Nusselt number of 112. Comparing our simulation result to the formula’s answer shows a difference of only 4.5%. This very small error proves that our CFD model is highly accurate. The simulation shows that the heat transfer is strongest at the front stagnation point and gets weaker as the fluid flows around to the back. The most important achievement of this simulation is proving with a tiny 4.5% error that our CFD model is a reliable and trustworthy tool, allowing engineers to confidently design advanced cooling systems with nanofluids, saving time and reducing the need for costly physical experiments.

The velocity contour provides a professional visual of the fluid flowing around the sphere. This professional visual clearly shows the fluid stopping at the very front of the sphere, creating a “stagnation point.” Behind the sphere, a “wake region” forms where the fluid swirls in small circles. This flow pattern is a classic example of forced convection over a sphere and perfectly matches what physics books teach us. Our ANSYS Fluent simulation used this flow data to calculate a Nusselt number of 106.92.

Figure 1: Velocity distribution from the Nusselt Number CFD Validation, showing the stagnation point and wake region.